class.ilTree.php

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<?php
/* Copyright (c) 1998-2009 ILIAS open source, Extended GPL, see docs/LICENSE */
 
define("IL_LAST_NODE", -2);
define("IL_FIRST_NODE", -1);
 
include_once './Services/Tree/exceptions/class.ilInvalidTreeStructureException.php';
 
class ilTree
{
        const POS_LAST_NODE = -2;
        const POS_FIRST_NODE = -1;
        
        
        const RELATION_CHILD = 1;               // including grand child
        const RELATION_PARENT = 2;              // including grand child
        const RELATION_SIBLING = 3;
        const RELATION_EQUALS = 4;
        const RELATION_NONE = 5;
        
        
        var $ilias;
 
 
        var $log;
 
        var $root_id;
 
        var $tree_id;
 
        var $table_tree;
 
        var $table_obj_data;
 
        var $table_obj_reference;
 
        var $ref_pk;
 
        var $obj_pk;
 
        var $tree_pk;
 
        var $gap;
 
        protected $depth_cache = array();
        protected $parent_cache = array();
        protected $in_tree_cache = array();
        
        private $tree_impl = NULL;
 
 
        function ilTree($a_tree_id, $a_root_id = 0)
        {
                global $ilDB,$ilErr,$ilias,$ilLog;
 
                // set db & error handler
                $this->ilDB = $ilDB;
 
                if (!isset($ilErr))
                {
                        $ilErr = new ilErrorHandling();
                        $ilErr->setErrorHandling(PEAR_ERROR_CALLBACK,array($ilErr,'errorHandler'));
                }
                else
                {
                        $this->ilErr = $ilErr;
                }
 
                $this->lang_code = "en";
                
                if (!isset($a_tree_id) or (func_num_args() == 0) )
                {
                        $this->ilErr->raiseError(get_class($this)."::Constructor(): No tree_id given!",$this->ilErr->WARNING);
                }
 
                if (func_num_args() > 2)
                {
                        $this->ilErr->raiseError(get_class($this)."::Constructor(): Wrong parameter count!",$this->ilErr->WARNING);
                }
 
                // CREATE LOGGER INSTANCE
                $this->log = $ilLog;
 
                //init variables
                if (empty($a_root_id))
                {
                        $a_root_id = ROOT_FOLDER_ID;
                }
 
                $this->tree_id            = $a_tree_id;
                $this->root_id            = $a_root_id;
                $this->table_tree     = 'tree';
                $this->table_obj_data = 'object_data';
                $this->table_obj_reference = 'object_reference';
                $this->ref_pk = 'ref_id';
                $this->obj_pk = 'obj_id';
                $this->tree_pk = 'tree';
 
                $this->use_cache = true;
 
                // If cache is activated, cache object translations to improve performance
                $this->translation_cache = array();
                $this->parent_type_cache = array();
 
                // By default, we create gaps in the tree sequence numbering for 50 nodes
                $this->gap = 50;
                
                
                // init tree implementation 
                $this->initTreeImplementation();
        }
        
        public function initTreeImplementation()
        {
                global $ilDB;
                
                
                if(!is_object($GLOBALS['ilSetting']) or $GLOBALS['ilSetting']->getModule() != 'common')
                {
                        include_once './Services/Administration/classes/class.ilSetting.php';
                        $setting = new ilSetting('common');
                }
                else
                {
                        $setting = $GLOBALS['ilSetting'];
                }
                
                if($this->__isMainTree())
                {
                        if($setting->get('main_tree_impl','ns') == 'ns')
                        {
                                #$GLOBALS['ilLog']->write(__METHOD__.': Using nested set.');
                                include_once './Services/Tree/classes/class.ilNestedSetTree.php';
                                $this->tree_impl = new ilNestedSetTree($this);
                        }
                        else
                        {
                                #$GLOBALS['ilLog']->write(__METHOD__.': Using materialized path.');
                                include_once './Services/Tree/classes/class.ilMaterializedPathTree.php';
                                $this->tree_impl = new ilMaterializedPathTree($this);
                        }
                }
                else
                {
                        #$GLOBALS['ilLog']->write(__METHOD__.': Using netsted set for non main tree.');
                        include_once './Services/Tree/classes/class.ilNestedSetTree.php';
                        $this->tree_impl = new ilNestedSetTree($this);
                }
        }
        
        public function getTreeImplementation()
        {
                return $this->tree_impl;
        }
        
        public function useCache($a_use = true)
        {
                $this->use_cache = $a_use;
        }
        
        public function isCacheUsed()
        {
                return $this->__isMainTree() and $this->use_cache;
        }
        
        public function getDepthCache()
        {
                return (array) $this->depth_cache;
        }
        
        public function getParentCache()
        {
                return (array) $this->parent_cache;
        }
        
        function initLangCode()
        {
                global $ilUser;
                
                // lang_code is only required in $this->fetchnodedata
                if (!is_object($ilUser))
                {
                        $this->lang_code = "en";
                }
                else
                {
                        $this->lang_code = $ilUser->getCurrentLanguage();
                }
        }
        
        public function getTreeTable()
        {
                return $this->table_tree;
        }
        
        public function getObjectDataTable()
        {
                return $this->table_obj_data;
        }
        
        public function getTreePk()
        {
                return $this->tree_pk;
        }
        
        public function getTableReference()
        {
                return $this->table_obj_reference;
        }
        
        public function getGap()
        {
                return $this->gap;
        }
        
        /***
         * reset in tree cache
         */
        public function resetInTreeCache()
        {
                $this->in_tree_cache = array();
        }
 
 
        function setTableNames($a_table_tree,$a_table_obj_data,$a_table_obj_reference = "")
        {
                if (!isset($a_table_tree) or !isset($a_table_obj_data))
                {
                        $this->ilErr->raiseError(get_class($this)."::setTableNames(): Missing parameter! ".
                                                                "tree table: ".$a_table_tree." object data table: ".$a_table_obj_data,$this->ilErr->WARNING);
                }
 
                $this->table_tree = $a_table_tree;
                $this->table_obj_data = $a_table_obj_data;
                $this->table_obj_reference = $a_table_obj_reference;
                
                $this->initTreeImplementation();
 
                return true;
        }
 
        function setReferenceTablePK($a_column_name)
        {
                if (!isset($a_column_name))
                {
                        $this->ilErr->raiseError(get_class($this)."::setReferenceTablePK(): No column name given!",$this->ilErr->WARNING);
                }
 
                $this->ref_pk = $a_column_name;
                return true;
        }
 
        function setObjectTablePK($a_column_name)
        {
                if (!isset($a_column_name))
                {
                        $this->ilErr->raiseError(get_class($this)."::setObjectTablePK(): No column name given!",$this->ilErr->WARNING);
                }
 
                $this->obj_pk = $a_column_name;
                return true;
        }
 
        function setTreeTablePK($a_column_name)
        {
                if (!isset($a_column_name))
                {
                        $this->ilErr->raiseError(get_class($this)."::setTreeTablePK(): No column name given!",$this->ilErr->WARNING);
                }
 
                $this->tree_pk = $a_column_name;
                return true;
        }
 
        function buildJoin()
        {
                if ($this->table_obj_reference)
                {
                        // Use inner join instead of left join to improve performance
                        return "JOIN ".$this->table_obj_reference." ON ".$this->table_tree.".child=".$this->table_obj_reference.".".$this->ref_pk." ".
                                   "JOIN ".$this->table_obj_data." ON ".$this->table_obj_reference.".".$this->obj_pk."=".$this->table_obj_data.".".$this->obj_pk." ";
                }
                else
                {
                        // Use inner join instead of left join to improve performance
                        return "JOIN ".$this->table_obj_data." ON ".$this->table_tree.".child=".$this->table_obj_data.".".$this->obj_pk." ";
                }
        }
        
        public function getRelation($a_node_a, $a_node_b)
        {
                return $this->getRelationOfNodes(
                                        $this->getNodeTreeData($a_node_a),
                                        $this->getNodeTreeData($a_node_b)
                );
        }
        
        public function getRelationOfNodes($a_node_a_arr, $a_node_b_arr)
        {
                return $this->getTreeImplementation()->getRelation($a_node_a_arr, $a_node_b_arr);
        }
        
        public function getChildIds($a_node)
        {
                global $ilDB;
                
                $query = 'SELECT * FROM tree '.
                                'WHERE parent = '.$ilDB->quote($a_node,'integer').' '.
                                'AND tree > '.$ilDB->quote(0,'integer');
                $res = $ilDB->query($query);
                
                $childs = array();
                while($row = $res->fetchRow(DB_FETCHMODE_OBJECT))
                {
                        $childs[] = $row->child;
                }
                return $childs;
        }
 
        function getChilds($a_node_id, $a_order = "", $a_direction = "ASC")
        {
                global $ilBench,$ilDB, $ilObjDataCache, $ilUser;
                
                if (!isset($a_node_id))
                {
                        $message = get_class($this)."::getChilds(): No node_id given!";
                        $this->ilErr->raiseError($message,$this->ilErr->WARNING);
                }
 
                // init childs
                $childs = array();
 
                // number of childs
                $count = 0;
 
                // init order_clause
                $order_clause = "";
 
                // set order_clause if sort order parameter is given
                if (!empty($a_order))
                {
                        $order_clause = "ORDER BY ".$a_order." ".$a_direction;
                }
                else
                {
                        $order_clause = "ORDER BY ".$this->table_tree.".lft";
                }
 
                         
                $query = sprintf('SELECT * FROM '.$this->table_tree.' '.
                                $this->buildJoin().
                                "WHERE parent = %s " .
                                "AND ".$this->table_tree.".".$this->tree_pk." = %s ".
                                $order_clause,
                                $ilDB->quote($a_node_id,'integer'),
                                $ilDB->quote($this->tree_id,'integer'));
 
                $res = $ilDB->query($query);
                
                if(!$count = $res->numRows())
                {
                        return array();
                }
 
                // get rows and object ids
                $rows = array();
                while($r = $ilDB->fetchAssoc($res))
                {
                        $rows[] = $r;
                        $obj_ids[] = $r["obj_id"];
                }
 
                // preload object translation information
                if ($this->__isMainTree() && $this->isCacheUsed() && is_object($ilObjDataCache) &&
                        is_object($ilUser) && $this->lang_code == $ilUser->getLanguage() && !$this->oc_preloaded[$a_node_id])
                {
//                      $ilObjDataCache->preloadTranslations($obj_ids, $this->lang_code);
                        $ilObjDataCache->preloadObjectCache($obj_ids, $this->lang_code);
                        $this->fetchTranslationFromObjectDataCache($obj_ids);
                        $this->oc_preloaded[$a_node_id] = true;
                }
 
                foreach ($rows as $row)
                {
                        $childs[] = $this->fetchNodeData($row);
 
                        // Update cache of main tree
                        if ($this->__isMainTree())
                        {
                                #$GLOBALS['ilLog']->write(__METHOD__.': Storing in tree cache '.$row['child'].' = true');
                                $this->in_tree_cache[$row['child']] = $row['tree'] == 1;
                        }
                }
                $childs[$count - 1]["last"] = true;
                return $childs;
        }
 
        function getFilteredChilds($a_filter,$a_node,$a_order = "",$a_direction = "ASC")
        {
                $childs = $this->getChilds($a_node,$a_order,$a_direction);
 
                foreach($childs as $child)
                {
                        if(!in_array($child["type"],$a_filter))
                        {
                                $filtered[] = $child;
                        }
                }
                return $filtered ? $filtered : array();
        }
 
 
        function getChildsByType($a_node_id,$a_type)
        {
                global $ilDB;
                
                if (!isset($a_node_id) or !isset($a_type))
                {
                        $message = get_class($this)."::getChildsByType(): Missing parameter! node_id:".$a_node_id." type:".$a_type;
                        $this->ilErr->raiseError($message,$this->ilErr->WARNING);
                }
 
        if ($a_type=='rolf' && $this->table_obj_reference) {
            // Performance optimization: A node can only have exactly one
            // role folder as its child. Therefore we don't need to sort the
            // results, and we can let the database know about the expected limit.
            $ilDB->setLimit(1,0);
            $query = sprintf("SELECT * FROM ".$this->table_tree." ".
                $this->buildJoin().
                "WHERE parent = %s ".
                "AND ".$this->table_tree.".".$this->tree_pk." = %s ".
                "AND ".$this->table_obj_data.".type = %s ",
                $ilDB->quote($a_node_id,'integer'),
                $ilDB->quote($this->tree_id,'integer'),
                $ilDB->quote($a_type,'text'));
        } else {
            $query = sprintf("SELECT * FROM ".$this->table_tree." ".
                $this->buildJoin().
                "WHERE parent = %s ".
                "AND ".$this->table_tree.".".$this->tree_pk." = %s ".
                "AND ".$this->table_obj_data.".type = %s ".
                "ORDER BY ".$this->table_tree.".lft",
                $ilDB->quote($a_node_id,'integer'),
                $ilDB->quote($this->tree_id,'integer'),
                $ilDB->quote($a_type,'text'));
        }
                $res = $ilDB->query($query);
                
                // init childs
                $childs = array();
                while($row = $ilDB->fetchAssoc($res))
                {
                        $childs[] = $this->fetchNodeData($row);
                }
                
                return $childs ? $childs : array();
        }
 
 
        public function getChildsByTypeFilter($a_node_id,$a_types,$a_order = "",$a_direction = "ASC")
        {
                global $ilDB;
                
                if (!isset($a_node_id) or !$a_types)
                {
                        $message = get_class($this)."::getChildsByType(): Missing parameter! node_id:".$a_node_id." type:".$a_types;
                        $this->ilErr->raiseError($message,$this->ilErr->WARNING);
                }
        
                $filter = ' ';
                if($a_types)
                {
                        $filter = 'AND '.$this->table_obj_data.'.type IN('.implode(',',ilUtil::quoteArray($a_types)).') ';
                }
 
                // set order_clause if sort order parameter is given
                if (!empty($a_order))
                {
                        $order_clause = "ORDER BY ".$a_order." ".$a_direction;
                }
                else
                {
                        $order_clause = "ORDER BY ".$this->table_tree.".lft";
                }
                
                $query = 'SELECT * FROM '.$this->table_tree.' '.
                        $this->buildJoin().
                        'WHERE parent = '.$ilDB->quote($a_node_id,'integer').' '.
                        'AND '.$this->table_tree.'.'.$this->tree_pk.' = '.$ilDB->quote($this->tree_id,'integer').' '.
                        $filter.
                        $order_clause;
                
                $res = $ilDB->query($query);
                while($row = $ilDB->fetchAssoc($res))
                {
                        $childs[] = $this->fetchNodeData($row);
                }       
                
                return $childs ? $childs : array();
        }
        
        public function insertNode($a_node_id, $a_parent_id, $a_pos = IL_LAST_NODE, $a_reset_deletion_date = false)
        {
                global $ilDB;
                
//echo "+$a_node_id+$a_parent_id+";
                // CHECK node_id and parent_id > 0 if in main tree
                if($this->__isMainTree())
                {
                        if($a_node_id <= 1 or $a_parent_id <= 0)
                        {
                                $GLOBALS['ilLog']->logStack();
                                $message = sprintf('%s::insertNode(): Invalid parameters! $a_node_id: %s $a_parent_id: %s',
                                                                   get_class($this),
                                                                   $a_node_id,
                                                                   $a_parent_id);
                                $this->log->write($message,$this->log->FATAL);
                                $this->ilErr->raiseError($message,$this->ilErr->WARNING);
                        }
                }
 
 
                if (!isset($a_node_id) or !isset($a_parent_id))
                {
                        $GLOBALS['ilLog']->logStack();
                        $this->ilErr->raiseError(get_class($this)."::insertNode(): Missing parameter! ".
                                "node_id: ".$a_node_id." parent_id: ".$a_parent_id,$this->ilErr->WARNING);
                }
                if ($this->isInTree($a_node_id))
                {
                        $this->ilErr->raiseError(get_class($this)."::insertNode(): Node ".$a_node_id." already in tree ".
                                                                         $this->table_tree."!",$this->ilErr->WARNING);
                }
 
                $this->getTreeImplementation()->insertNode($a_node_id, $a_parent_id, $a_pos);
                
                $this->in_tree_cache[$a_node_id] = true;
 
                // reset deletion date
                if ($a_reset_deletion_date)
                {
                        ilObject::_resetDeletedDate($a_node_id);
                }
        }
        
        public function getFilteredSubTree($a_node_id,$a_filter = array())
        {
                $node = $this->getNodeData($a_node_id);
                
                $first = true;
                $depth = 0;
                foreach($this->getSubTree($node) as $subnode)
                {
                        if($depth and $subnode['depth'] > $depth)
                        {
                                continue;
                        }
                        if(!$first and in_array($subnode['type'],$a_filter))
                        {
                                $depth = $subnode['depth'];
                                $first = false;
                                continue;
                        }
                        $depth = 0;
                        $first = false;
                        $filtered[] = $subnode; 
                }
                return $filtered ? $filtered : array();
        }
        
        public function getSubTreeIds($a_ref_id)
        {
                return $this->getTreeImplementation()->getSubTreeIds($a_ref_id);
        }
        
 
        function getSubTree($a_node,$a_with_data = true, $a_type = "")
        {
                global $ilDB;
                
                if (!is_array($a_node))
                {
                        $GLOBALS['ilLog']->logStack();
                        throw new InvalidArgumentException(__METHOD__.': wrong datatype for node data given');
                }
 
                /*
                if($a_node['lft'] < 1 or $a_node['rgt'] < 2)
                {
                        $GLOBALS['ilLog']->logStack();
                        $message = sprintf('%s: Invalid node given! $a_node["lft"]: %s $a_node["rgt"]: %s',
                                                                   __METHOD__,
                                                                   $a_node['lft'],
                                                                   $a_node['rgt']);
 
                        throw new InvalidArgumentException($message);
                }
                */
                
                $query = $this->getTreeImplementation()->getSubTreeQuery($a_node, $a_type);
                $res = $ilDB->query($query);
                while($row = $ilDB->fetchAssoc($res))
                {
                        if($a_with_data)
                        {
                                $subtree[] = $this->fetchNodeData($row);
                        }
                        else
                        {
                                $subtree[] = $row['child'];
                        }
                        // the lm_data "hack" should be removed in the trunk during an alpha
                        if($this->__isMainTree() || $this->table_tree == "lm_tree")
                        {
                                $this->in_tree_cache[$row['child']] = true;
                        }
                }
                return $subtree ? $subtree : array();
        }
 
        function getSubTreeTypes($a_node,$a_filter = 0)
        {
                $a_filter = $a_filter ? $a_filter : array();
 
                foreach($this->getSubtree($this->getNodeData($a_node)) as $node)
                {
                        if(in_array($node["type"],$a_filter))
                        {
                                continue;
                        }
                        $types["$node[type]"] = $node["type"];
                }
                return $types ? $types : array();
        }
 
        function deleteTree($a_node)
        {
                global $ilDB;
 
                $GLOBALS['ilLog']->write(__METHOD__.': Delete tree with node '. $a_node);
                
                if (!is_array($a_node))
                {
                        $GLOBALS['ilLog']->logStack();
                        throw new InvalidArgumentException(__METHOD__.': Wrong datatype for node data!');
                }
                
                $GLOBALS['ilLog']->write(__METHOD__.': '. $this->tree_pk);
                
                if($this->__isMainTree() )
                {
                        // @todo normally this part is not executed, since the subtree is first 
                        // moved to trash and then deleted.
                        if(!$this->__checkDelete($a_node))
                        {
                                $GLOBALS['ilLog']->logStack();
                                throw new ilInvalidTreeStructureException('Deletion canceled due to invalid tree structure.' . print_r($a_node,true));
                        }
                }
 
                $this->getTreeImplementation()->deleteTree($a_node['child']);
                
                $this->resetInTreeCache();
                
        }
 
        function getPathFull($a_endnode_id, $a_startnode_id = 0)
        {
                $pathIds =& $this->getPathId($a_endnode_id, $a_startnode_id);
 
                // We retrieve the full path in a single query to improve performance
        global $ilDB;
 
                // Abort if no path ids were found
                if (count($pathIds) == 0)
                {
                        return null;
                }
 
                $inClause = 'child IN (';
                for ($i=0; $i < count($pathIds); $i++)
                {
                        if ($i > 0) $inClause .= ',';
                        $inClause .= $ilDB->quote($pathIds[$i],'integer');
                }
                $inClause .= ')';
 
                $q = 'SELECT * '.
                        'FROM '.$this->table_tree.' '.
            $this->buildJoin().' '.
                        'WHERE '.$inClause.' '.
            'AND '.$this->table_tree.'.'.$this->tree_pk.' = '.$this->ilDB->quote($this->tree_id,'integer').' '.
                        'ORDER BY depth';
                $r = $ilDB->query($q);
 
                $pathFull = array();
                while ($row = $r->fetchRow(DB_FETCHMODE_ASSOC))
                {
                        $pathFull[] = $this->fetchNodeData($row);
 
                        // Update cache
                        if ($this->__isMainTree())
                        {
                                #$GLOBALS['ilLog']->write(__METHOD__.': Storing in tree cache '.$row['child']);
                                $this->in_tree_cache[$row['child']] = $row['tree'] == 1;
                        }
                }
                return $pathFull;
        }
        
 
        function preloadDepthParent($a_node_ids)
        {
                global $ilDB;
 
                if (!$this->__isMainTree() || !is_array($a_node_ids) || !$this->isCacheUsed())
                {
                        return;
                }
 
                $res = $ilDB->query('SELECT t.depth, t.parent, t.child '.
                        'FROM '.$this->table_tree.' t '.
                        'WHERE '.$ilDB->in("child", $a_node_ids, false, "integer").
                        'AND '.$this->tree_pk.' = '.$ilDB->quote($this->tree_id, "integer"));
                while ($row = $ilDB->fetchAssoc($res))
                {
                        $this->depth_cache[$row["child"]] = $row["depth"];
                        $this->parent_cache[$row["child"]] = $row["parent"];
                }
        }
 
        public function getPathId($a_endnode_id, $a_startnode_id = 0)
        {
                if(!$a_endnode_id)
                {
                        $GLOBALS['ilLog']->logStack();
                        throw new InvalidArgumentException(__METHOD__.': No endnode given!');
                }
                
                // path id cache
                if ($this->isCacheUsed() && isset($this->path_id_cache[$a_endnode_id][$a_startnode_id]))
                {
//echo "<br>getPathIdhit";
                        return $this->path_id_cache[$a_endnode_id][$a_startnode_id];
                }
//echo "<br>miss";
 
                $pathIds = $this->getTreeImplementation()->getPathIds($a_endnode_id, $a_startnode_id);
                
                if($this->__isMainTree())
                {
                        $this->path_id_cache[$a_endnode_id][$a_startnode_id] = $pathIds;
                }
                return $pathIds;
        }
 
        // BEGIN WebDAV: getNodePathForTitlePath function added
        function getNodePathForTitlePath($titlePath, $a_startnode_id = null)
        {
                global $ilDB, $log;
                //$log->write('getNodePathForTitlePath('.implode('/',$titlePath));
                
                // handle empty title path
                if ($titlePath == null || count($titlePath) == 0)
                {
                        if ($a_startnode_id == 0)
                        {
                                return null;
                        }
                        else
                        {
                                return $this->getNodePath($a_startnode_id);
                        }
                }
 
                // fetch the node path up to the startnode
                if ($a_startnode_id != null && $a_startnode_id != 0)
                {
                        // Start using the node path to the root of the relative path
                        $nodePath = $this->getNodePath($a_startnode_id);
                        $parent = $a_startnode_id;
                }
                else
                {
                        // Start using the root of the tree
                        $nodePath = array();
                        $parent = 0;
                }
 
                
                // Convert title path into Unicode Normal Form C
                // This is needed to ensure that we can compare title path strings with
                // strings from the database.
                require_once('include/Unicode/UtfNormal.php');
                include_once './Services/Utilities/classes/class.ilStr.php';
                $inClause = 'd.title IN (';
                for ($i=0; $i < count($titlePath); $i++)
                {
                        $titlePath[$i] = ilStr::strToLower(UtfNormal::toNFC($titlePath[$i]));
                        if ($i > 0) $inClause .= ',';
                        $inClause .= $ilDB->quote($titlePath[$i],'text');
                }
                $inClause .= ')';
 
                // Fetch all rows that are potential path elements
                if ($this->table_obj_reference)
                {
                        $joinClause = 'JOIN '.$this->table_obj_reference.'  r ON t.child = r.'.$this->ref_pk.' '.
                                'JOIN '.$this->table_obj_data.' d ON r.'.$this->obj_pk.' = d.'.$this->obj_pk;
                }
                else
                {
                        $joinClause = 'JOIN '.$this->table_obj_data.'  d ON t.child = d.'.$this->obj_pk;
                }
                // The ORDER BY clause in the following SQL statement ensures that,
                // in case of a multiple objects with the same title, always the Object
                // with the oldest ref_id is chosen.
                // This ensure, that, if a new object with the same title is added,
                // WebDAV clients can still work with the older object.
                $q = 'SELECT t.depth, t.parent, t.child, d.'.$this->obj_pk.' obj_id, d.type, d.title '.
                        'FROM '.$this->table_tree.'  t '.
                        $joinClause.' '.
                        'WHERE '.$inClause.' '.
                        'AND t.depth <= '.(count($titlePath)+count($nodePath)).' '.
                        'AND t.tree = 1 '.
                        'ORDER BY t.depth, t.child ASC';
                $r = $ilDB->query($q);
                
                $rows = array();
                while ($row = $r->fetchRow(DB_FETCHMODE_ASSOC))
                {
                        $row['title'] = UtfNormal::toNFC($row['title']);
                        $row['ref_id'] = $row['child'];
                        $rows[] = $row;
                }
 
                // Extract the path elements from the fetched rows
                for ($i = 0; $i < count($titlePath); $i++) {
                        $pathElementFound = false; 
                        foreach ($rows as $row) {
                                if ($row['parent'] == $parent && 
                                ilStr::strToLower($row['title']) == $titlePath[$i])
                                {
                                        // FIXME - We should test here, if the user has 
                                        // 'visible' permission for the object.
                                        $nodePath[] = $row;
                                        $parent = $row['child'];
                                        $pathElementFound = true;
                                        break;
                                }
                        }
                        // Abort if we haven't found a path element for the current depth
                        if (! $pathElementFound)
                        {
                                //$log->write('ilTree.getNodePathForTitlePath('.var_export($titlePath,true).','.$a_startnode_id.'):null');
                                return null;
                        }
                }
                // Return the node path
                //$log->write('ilTree.getNodePathForTitlePath('.var_export($titlePath,true).','.$a_startnode_id.'):'.var_export($nodePath,true));
                return $nodePath;
        }
        // END WebDAV: getNodePathForTitlePath function added
        // END WebDAV: getNodePath function added
        function getNodePath($a_endnode_id, $a_startnode_id = 0)
        {
                global $ilDB;
 
                $pathIds = $this->getPathId($a_endnode_id, $a_startnode_id);
 
                // Abort if no path ids were found
                if (count($pathIds) == 0)
                {
                        return null;
                }
 
                
                $types = array();
                $data = array();
                for ($i = 0; $i < count($pathIds); $i++)
                {
                        $types[] = 'integer';
                        $data[] = $pathIds[$i];
                }
 
                $query = 'SELECT t.depth,t.parent,t.child,d.obj_id,d.type,d.title '.
                        'FROM '.$this->table_tree.' t '.
                        'JOIN '.$this->table_obj_reference.' r ON r.ref_id = t.child '.
                        'JOIN '.$this->table_obj_data.' d ON d.obj_id = r.obj_id '.
                        'WHERE '.$ilDB->in('t.child',$data,false,'integer').' '.
                        'ORDER BY t.depth ';
                        
                $res = $ilDB->queryF($query,$types,$data);
 
                $titlePath = array();
                while ($row = $ilDB->fetchAssoc($res))
                {
                        $titlePath[] = $row;
                }
                return $titlePath;
        }
        // END WebDAV: getNodePath function added
 
        function checkTree()
        {
                global $ilDB;
                
                $types = array('integer');
                $query = 'SELECT lft,rgt FROM '.$this->table_tree.' '.
                        'WHERE '.$this->tree_pk.' = %s ';
                
                $res = $ilDB->queryF($query,$types,array($this->tree_id));
                while ($row = $ilDB->fetchObject($res))
                {
                        $lft[] = $row->lft;
                        $rgt[] = $row->rgt;
                }
 
                $all = array_merge($lft,$rgt);
                $uni = array_unique($all);
 
                if (count($all) != count($uni))
                {
                        $message = sprintf('%s::checkTree(): Tree is corrupted!',
                                                           get_class($this));
 
                        $this->log->write($message,$this->log->FATAL);
                        $this->ilErr->raiseError($message,$this->ilErr->WARNING);
                }
 
                return true;
        }
 
        function checkTreeChilds($a_no_zero_child = true)
        {
                global $ilDB;
                
                $query = 'SELECT * FROM '.$this->table_tree.' '.
                                'WHERE '.$this->tree_pk.' = %s '.
                                'ORDER BY lft';
                $r1 = $ilDB->queryF($query,array('integer'),array($this->tree_id));
                
                while ($row = $ilDB->fetchAssoc($r1))
                {
//echo "tree:".$row[$this->tree_pk].":lft:".$row["lft"].":rgt:".$row["rgt"].":child:".$row["child"].":<br>";
                        if (($row["child"] == 0) && $a_no_zero_child)
                        {
                                $this->ilErr->raiseError(get_class($this)."::checkTreeChilds(): Tree contains child with ID 0!",$this->ilErr->WARNING);
                        }
 
                        if ($this->table_obj_reference)
                        {
                                // get object reference data
                                $query = 'SELECT * FROM '.$this->table_obj_reference.' WHERE '.$this->ref_pk.' = %s ';
                                $r2 = $ilDB->queryF($query,array('integer'),array($row['child']));
                                
//echo "num_childs:".$r2->numRows().":<br>";
                                if ($r2->numRows() == 0)
                                {
                                        $this->ilErr->raiseError(get_class($this)."::checkTree(): No Object-to-Reference entry found for ID ".
                                                $row["child"]."!",$this->ilErr->WARNING);
                                }
                                if ($r2->numRows() > 1)
                                {
                                        $this->ilErr->raiseError(get_class($this)."::checkTree(): More Object-to-Reference entries found for ID ".
                                                $row["child"]."!",$this->ilErr->WARNING);
                                }
 
                                // get object data
                                $obj_ref = $ilDB->fetchAssoc($r2);
 
                                $query = 'SELECT * FROM '.$this->table_obj_data.' WHERE '.$this->obj_pk.' = %s';
                                $r3 = $ilDB->queryF($query,array('integer'),array($obj_ref[$this->obj_pk]));
                                if ($r3->numRows() == 0)
                                {
                                        $this->ilErr->raiseError(get_class($this)."::checkTree(): No child found for ID ".
                                                $obj_ref[$this->obj_pk]."!",$this->ilErr->WARNING);
                                }
                                if ($r3->numRows() > 1)
                                {
                                        $this->ilErr->raiseError(get_class($this)."::checkTree(): More childs found for ID ".
                                                $obj_ref[$this->obj_pk]."!",$this->ilErr->WARNING);
                                }
 
                        }
                        else
                        {
                                // get only object data
                                $query = 'SELECT * FROM '.$this->table_obj_data.' WHERE '.$this->obj_pk.' = %s';
                                $r2 = $ilDB->queryF($query,array('integer'),array($row['child']));
//echo "num_childs:".$r2->numRows().":<br>";
                                if ($r2->numRows() == 0)
                                {
                                        $this->ilErr->raiseError(get_class($this)."::checkTree(): No child found for ID ".
                                                $row["child"]."!",$this->ilErr->WARNING);
                                }
                                if ($r2->numRows() > 1)
                                {
                                        $this->ilErr->raiseError(get_class($this)."::checkTree(): More childs found for ID ".
                                                $row["child"]."!",$this->ilErr->WARNING);
                                }
                        }
                }
 
                return true;
        }
 
        public function getMaximumDepth()
        {
                global $ilDB;
                
                $query = 'SELECT MAX(depth) depth FROM '.$this->table_tree;
                $res = $ilDB->query($query);            
                
                $row = $ilDB->fetchAssoc($res);
                return $row['depth'];
        }
 
        function getDepth($a_node_id)
        {
                global $ilDB;
                
                if ($a_node_id)
                {
                        $query = 'SELECT depth FROM '.$this->table_tree.' '.
                                'WHERE child = %s '.
                                'AND '.$this->tree_pk.' = %s ';
                        $res = $ilDB->queryF($query,array('integer','integer'),array($a_node_id,$this->tree_id));
                        $row = $ilDB->fetchObject($res);
 
                        return $row->depth;
                }
                else
                {
                        return 1;
                }
        }
        
        public function getNodeTreeData($a_node_id)
        {
                global $ilDB;
                
                if(!$a_node_id)
                {
                        $GLOBALS['ilLog']->logStack();
                        throw new InvalidArgumentException('Missing or empty parameter $a_node_id: '. $a_node_id);
                }
                
                $query = 'SELECT * FROM '.$this->table_tree.' '.
                                'WHERE child = '.$ilDB->quote($a_node_id,'integer');
                $res = $ilDB->query($query);
                while($row = $res->fetchRow(DB_FETCHMODE_ASSOC))
                {
                        return $row;
                }
                return array();
        }
 
 
        // BEGIN WebDAV: Pass tree id to this method
        //function getNodeData($a_node_id)
        function getNodeData($a_node_id, $a_tree_pk = null)
        // END PATCH WebDAV: Pass tree id to this method
        {
                global $ilDB;
                
                if (!isset($a_node_id))
                {
                        $GLOBALS['ilLog']->logStack();
                        $this->ilErr->raiseError(get_class($this)."::getNodeData(): No node_id given! ",$this->ilErr->WARNING);
                }
                if($this->__isMainTree())
                {
                        if($a_node_id < 1)
                        {
                                $message = sprintf('%s::getNodeData(): No valid parameter given! $a_node_id: %s',
                                                                   get_class($this),
                                                                   $a_node_id);
 
                                $this->log->write($message,$this->log->FATAL);
                                $this->ilErr->raiseError($message,$this->ilErr->WARNING);
                        }
                }
 
                // BEGIN WebDAV: Pass tree id to this method
                $query = 'SELECT * FROM '.$this->table_tree.' '.
                        $this->buildJoin().
                        'WHERE '.$this->table_tree.'.child = %s '.
                        'AND '.$this->table_tree.'.'.$this->tree_pk.' = %s ';
                $res = $ilDB->queryF($query,array('integer','integer'),array(
                        $a_node_id,
                        $a_tree_pk === null ? $this->tree_id : $a_tree_pk));
                // END WebDAV: Pass tree id to this method
                $row = $ilDB->fetchAssoc($res);
                $row[$this->tree_pk] = $this->tree_id;
 
                return $this->fetchNodeData($row);
        }
        
        function fetchNodeData($a_row)
        {
                global $objDefinition, $lng, $ilBench,$ilDB;
 
                //$ilBench->start("Tree", "fetchNodeData_getRow");
                $data = $a_row;
                $data["desc"] = $a_row["description"];  // for compability
                //$ilBench->stop("Tree", "fetchNodeData_getRow");
 
                // multilingual support systemobjects (sys) & categories (db)
                //$ilBench->start("Tree", "fetchNodeData_readDefinition");
                if (is_object($objDefinition))
                {
                        $translation_type = $objDefinition->getTranslationType($data["type"]);
                }
                //$ilBench->stop("Tree", "fetchNodeData_readDefinition");
 
                if ($translation_type == "sys")
                {
                        //$ilBench->start("Tree", "fetchNodeData_getLangData");
                        if ($data["type"] == "rolf" and $data["obj_id"] != ROLE_FOLDER_ID)
                        {
                                $data["description"] = $lng->txt("obj_".$data["type"]."_local_desc").$data["title"].$data["desc"];
                                $data["desc"] = $lng->txt("obj_".$data["type"]."_local_desc").$data["title"].$data["desc"];
                                $data["title"] = $lng->txt("obj_".$data["type"]."_local");
                        }
                        else
                        {
                                $data["title"] = $lng->txt("obj_".$data["type"]);
                                $data["description"] = $lng->txt("obj_".$data["type"]."_desc");
                                $data["desc"] = $lng->txt("obj_".$data["type"]."_desc");
                        }
                        //$ilBench->stop("Tree", "fetchNodeData_getLangData");
                }
                elseif ($translation_type == "db")
                {
 
                        // Try to retrieve object translation from cache
                        if ($this->isCacheUsed() &&
                                array_key_exists($data["obj_id"].'.'.$lang_code, $this->translation_cache)) {
 
                                $key = $data["obj_id"].'.'.$lang_code;
                                $data["title"] = $this->translation_cache[$key]['title'];
                                $data["description"] = $this->translation_cache[$key]['description'];
                                $data["desc"] = $this->translation_cache[$key]['desc'];
                        } 
                        else 
                        {
                                // Object translation is not in cache, read it from database
                                //$ilBench->start("Tree", "fetchNodeData_getTranslation");
                                $query = 'SELECT title,description FROM object_translation '.
                                        'WHERE obj_id = %s '.
                                        'AND lang_code = %s '.
                                        'AND NOT lang_default = %s';
 
                                $res = $ilDB->queryF($query,array('integer','text','integer'),array(
                                        $data['obj_id'],
                                        $this->lang_code,
                                        1));
                                $row = $ilDB->fetchObject($res);
 
                                if ($row)
                                {
                                        $data["title"] = $row->title;
                                        $data["description"] = ilUtil::shortenText($row->description,ilObject::DESC_LENGTH,true);
                                        $data["desc"] = $row->description;
                                }
                                //$ilBench->stop("Tree", "fetchNodeData_getTranslation");
 
                                // Store up to 1000 object translations in cache
                                if ($this->isCacheUsed() && count($this->translation_cache) < 1000)
                                {
                                        $key = $data["obj_id"].'.'.$lang_code;
                                        $this->translation_cache[$key] = array();
                                        $this->translation_cache[$key]['title'] = $data["title"] ;
                                        $this->translation_cache[$key]['description'] = $data["description"];
                                        $this->translation_cache[$key]['desc'] = $data["desc"];
                                }
                        }
                }
 
                // TODO: Handle this switch by module.xml definitions
                if($data['type'] == 'crsr' or $data['type'] == 'catr')
                {
                        include_once('./Services/ContainerReference/classes/class.ilContainerReference.php');
                        $data['title'] = ilContainerReference::_lookupTitle($data['obj_id']);
                }
 
                return $data ? $data : array();
        }
 
        protected function fetchTranslationFromObjectDataCache($a_obj_ids)
        {
                global $ilObjDataCache;
 
                if ($this->isCacheUsed() && is_array($a_obj_ids) && is_object($ilObjDataCache))
                {
                        foreach ($a_obj_ids as $id)
                        {
                                $this->translation_cache[$id.'.']['title'] = $ilObjDataCache->lookupTitle($id);
                                $this->translation_cache[$id.'.']['description'] = $ilObjDataCache->lookupDescription($id);;
                                $this->translation_cache[$id.'.']['desc'] =
                                        $this->translation_cache[$id.'.']['description'];
                        }
                }
        }
 
 
        function isInTree($a_node_id)
        {
                global $ilDB;
 
                if (!isset($a_node_id))
                {
                        return false;
                        #$this->ilErr->raiseError(get_class($this)."::getNodeData(): No node_id given! ",$this->ilErr->WARNING);
                }
                // is in tree cache
                if ($this->isCacheUsed() && isset($this->in_tree_cache[$a_node_id]))
                {
                        #$GLOBALS['ilLog']->write(__METHOD__.': Using in tree cache '.$a_node_id);
//echo "<br>in_tree_hit";
                        return $this->in_tree_cache[$a_node_id];
                }
 
                $query = 'SELECT * FROM '.$this->table_tree.' '.
                        'WHERE '.$this->table_tree.'.child = %s '.
                        'AND '.$this->table_tree.'.'.$this->tree_pk.' = %s';
                        
                $res = $ilDB->queryF($query,array('integer','integer'),array(
                        $a_node_id,
                        $this->tree_id));
 
                if ($res->numRows() > 0)
                {
                        if($this->__isMainTree())
                        {
                                #$GLOBALS['ilLog']->write(__METHOD__.': Storing in tree cache '.$a_node_id.' = true');
                                $this->in_tree_cache[$a_node_id] = true;
                        }
                        return true;
                }
                else
                {
                        if($this->__isMainTree())
                        {
                                #$GLOBALS['ilLog']->write(__METHOD__.': Storing in tree cache '.$a_node_id.' = false');
                                $this->in_tree_cache[$a_node_id] = false;
                        }
                        return false;
                }
        }
 
        public function getParentNodeData($a_node_id)
        {
                global $ilDB;
                global $ilLog;
                
                if (!isset($a_node_id))
                {
                        $ilLog->logStack();
                        throw new InvalidArgumentException(__METHOD__.': No node_id given!');
                }
 
                if ($this->table_obj_reference)
                {
                        // Use inner join instead of left join to improve performance
                        $innerjoin = "JOIN ".$this->table_obj_reference." ON v.child=".$this->table_obj_reference.".".$this->ref_pk." ".
                                                "JOIN ".$this->table_obj_data." ON ".$this->table_obj_reference.".".$this->obj_pk."=".$this->table_obj_data.".".$this->obj_pk." ";
                }
                else
                {
                        // Use inner join instead of left join to improve performance
                        $innerjoin = "JOIN ".$this->table_obj_data." ON v.child=".$this->table_obj_data.".".$this->obj_pk." ";
                }
 
                $query = 'SELECT * FROM '.$this->table_tree.' s, '.$this->table_tree.' v '.
                        $innerjoin.
                        'WHERE s.child = %s '.
                        'AND s.parent = v.child '.
                        'AND s.'.$this->tree_pk.' = %s '.
                        'AND v.'.$this->tree_pk.' = %s';
                $res = $ilDB->queryF($query,array('integer','integer','integer'),array(
                        $a_node_id,
                        $this->tree_id,
                        $this->tree_id));
                $row = $ilDB->fetchAssoc($res);
                return $this->fetchNodeData($row);
        }
 
        public function isGrandChild($a_startnode_id,$a_querynode_id)
        {
                return $this->getRelation($a_startnode_id, $a_querynode_id) == self::RELATION_PARENT;
        }
 
        function addTree($a_tree_id,$a_node_id = -1)
        {
                global $ilDB;
 
                // FOR SECURITY addTree() IS NOT ALLOWED ON MAIN TREE
                if($this->__isMainTree())
                {
                        $message = sprintf('%s::addTree(): Operation not allowed on main tree! $a_tree_if: %s $a_node_id: %s',
                                                           get_class($this),
                                                           $a_tree_id,
                                                           $a_node_id);
                        $this->log->write($message,$this->log->FATAL);
                        $this->ilErr->raiseError($message,$this->ilErr->WARNING);
                }
 
                if (!isset($a_tree_id))
                {
                        $this->ilErr->raiseError(get_class($this)."::addTree(): No tree_id given! ",$this->ilErr->WARNING);
                }
 
                if ($a_node_id <= 0)
                {
                        $a_node_id = $a_tree_id;
                }
 
                $query = 'INSERT INTO '.$this->table_tree.' ('.
                        $this->tree_pk.', child,parent,lft,rgt,depth) '.
                        'VALUES '.
                        '(%s,%s,%s,%s,%s,%s)';
                $res = $ilDB->manipulateF($query,array('integer','integer','integer','integer','integer','integer'),array(
                        $a_tree_id,
                        $a_node_id,
                        0,
                        1,
                        2,
                        1));
 
                return true;
        }
 
        public function getNodeDataByType($a_type)
        {
                global $ilDB;
                
                if(!isset($a_type) or (!is_string($a_type)))
                {
                        $GLOBALS['ilLog']->logStack();
                        throw new InvalidArgumentException('Type not given or wrong datatype');
                }
 
                $query = 'SELECT * FROM ' . $this->table_tree . ' ' .
                        $this->buildJoin().
                        'WHERE ' . $this->table_obj_data . '.type = ' . $this->ilDB->quote($a_type, 'text').
                        'AND ' . $this->table_tree . '.' . $this->tree_pk . ' = ' . $this->ilDB->quote($this->tree_id, 'integer');
 
                $res = $ilDB->query($query);
                $data = array();
                while($row = $ilDB->fetchAssoc($res))
                {
                        $data[] = $this->fetchNodeData($row);
                }
 
                return $data;
        }
 
        public function removeTree($a_tree_id)
        {
                global $ilDB;
                
                // OPERATION NOT ALLOWED ON MAIN TREE
                if($this->__isMainTree())
                {
                        $GLOBALS['ilLog']->logStack();
                        throw new InvalidArgumentException('Operation not allowed on main tree');
                }
                if (!$a_tree_id)
                {
                        $GLOBALS['ilLog']->logStack();
                        throw new InvalidArgumentException('Missing parameter tree id');
                }
 
                $query = 'DELETE FROM '.$this->table_tree.
                        ' WHERE '.$this->tree_pk.' = %s ';
                $ilDB->manipulateF($query,array('integer'),array($a_tree_id));
                return true;
        }
        
        public function moveToTrash($a_node_id, $a_set_deleted = false)
        {
                return $this->saveSubTree($a_node_id, $a_set_deleted);
        }
 
        public function saveSubTree($a_node_id, $a_set_deleted = false)
        {
                global $ilDB;
                
                if(!$a_node_id)
                {
                        $GLOBALS['ilLog']->logStack();
                        throw new InvalidArgumentException('No valid parameter given! $a_node_id: '.$a_node_id);
                }
 
                // LOCKED ###############################################
                if($this->__isMainTree())
                {
                        $ilDB->lockTables(
                                array(
                                        0 => array('name' => 'tree', 'type' => ilDB::LOCK_WRITE),
                                        1 => array('name' => 'object_reference', 'type' => ilDB::LOCK_WRITE)));
                }
 
                $query = $this->getTreeImplementation()->getSubTreeQuery($this->getNodeTreeData($a_node_id),'',false);
                $res = $ilDB->query($query);
 
                $subnodes = array();
                while($row = $res->fetchRow(DB_FETCHMODE_ASSOC))
                {
                        $subnodes[] = $row['child'];
                }
                
                if(!count($subnodes))
                {
                        // Possibly already deleted
                        // Unlock locked tables before returning
                        if($this->__isMainTree())
                        {
                                $ilDB->unlockTables();
                        }
                        return false;
                }
                
                if($a_set_deleted)
                {
                        include_once './Services/Object/classes/class.ilObject.php';
                        ilObject::setDeletedDates($subnodes);
                }
                
                // netsted set <=> mp
                $this->getTreeImplementation()->moveToTrash($a_node_id);
                
                if($this->__isMainTree())
                {
                        $ilDB->unlockTables();
                }
 
                // LOCKED ###############################################
                return true;
        }
 
        public function isDeleted($a_node_id)
        {
                return $this->isSaved($a_node_id);
        }
 
        public function isSaved($a_node_id)
        {
                global $ilDB;
                
                // is saved cache
                if ($this->isCacheUsed() && isset($this->is_saved_cache[$a_node_id]))
                {
//echo "<br>issavedhit";
                        return $this->is_saved_cache[$a_node_id];
                }
 
                $query = 'SELECT '.$this->tree_pk.' FROM '.$this->table_tree.' '.
                        'WHERE child = %s ';
                $res = $ilDB->queryF($query,array('integer'),array($a_node_id));
                $row = $ilDB->fetchAssoc($res);
 
                if ($row[$this->tree_pk] < 0)
                {
                        if($this->__isMainTree())
                        {
                                $this->is_saved_cache[$a_node_id] = true;
                        }
                        return true;
                }
                else
                {
                        if($this->__isMainTree())
                        {
                                $this->is_saved_cache[$a_node_id] = false;
                        }
                        return false;
                }
        }
 
        public function preloadDeleted($a_node_ids)
        {
                global $ilDB;
 
                if (!is_array($a_node_ids) || !$this->isCacheUsed())
                {
                        return;
                }
 
                $query = 'SELECT '.$this->tree_pk.', child FROM '.$this->table_tree.' '.
                        'WHERE '.$ilDB->in("child", $a_node_ids, false, "integer");
 
                $res = $ilDB->query($query);
                while ($row = $ilDB->fetchAssoc($res))
                {
                        if ($row[$this->tree_pk] < 0)
                        {
                                if($this->__isMainTree())
                                {
                                        $this->is_saved_cache[$row["child"]] = true;
                                }
                        }
                        else
                        {
                                if($this->__isMainTree())
                                {
                                        $this->is_saved_cache[$row["child"]] = false;
                                }
                        }
                }
        }
 
 
        function getSavedNodeData($a_parent_id)
        {
                global $ilDB;
                
                if (!isset($a_parent_id))
                {
                        $this->ilErr->raiseError(get_class($this)."::getSavedNodeData(): No node_id given!",$this->ilErr->WARNING);
                }
 
                $query = 'SELECT * FROM '.$this->table_tree.' '.
                        $this->buildJoin().
                        'WHERE '.$this->table_tree.'.'.$this->tree_pk.' < %s '.
                        'AND '.$this->table_tree.'.parent = %s';
                $res = $ilDB->queryF($query,array('integer','integer'),array(
                        0,
                        $a_parent_id));
 
                while($row = $ilDB->fetchAssoc($res))
                {
                        $saved[] = $this->fetchNodeData($row);
                }
 
                return $saved ? $saved : array();
        }
        
        function getSavedNodeObjIds(array $a_obj_ids)
        {
                global $ilDB;
                
                $query = 'SELECT '.$this->table_obj_data.'.obj_id FROM '.$this->table_tree.' '.
                        $this->buildJoin().
                        'WHERE '.$this->table_tree.'.'.$this->tree_pk.' < '.$ilDB->quote(0, 'integer').' '.
                        'AND '.$ilDB->in($this->table_obj_data.'.obj_id', $a_obj_ids, '', 'integer');
                $res = $ilDB->query($query);
                while($row = $ilDB->fetchAssoc($res))
                {
                        $saved[] = $row['obj_id'];
                }
 
                return $saved ? $saved : array();
        }
 
        function getParentId($a_node_id)
        {
                global $ilDB;
                
                if (!isset($a_node_id))
                {
                        $this->ilErr->raiseError(get_class($this)."::getParentId(): No node_id given! ",$this->ilErr->WARNING);
                }
 
                $query = 'SELECT parent FROM '.$this->table_tree.' '.
                        'WHERE child = %s '.
                        'AND '.$this->tree_pk.' = %s ';
                $res = $ilDB->queryF($query,array('integer','integer'),array(
                        $a_node_id,
                        $this->tree_id));
 
                $row = $ilDB->fetchObject($res);
                return $row->parent;
        }
 
        function getLeftValue($a_node_id)
        {
                global $ilDB;
                
                if (!isset($a_node_id))
                {
                        $this->ilErr->raiseError(get_class($this)."::getLeftValued(): No node_id given! ",$this->ilErr->WARNING);
                }
 
                $query = 'SELECT lft FROM '.$this->table_tree.' '.
                        'WHERE child = %s '.
                        'AND '.$this->tree_pk.' = %s ';
                $res = $ilDB->queryF($query,array('integer','integer'),array(
                        $a_node_id,
                        $this->tree_id));
                $row = $ilDB->fetchObject($res);
                return $row->lft;
        }
 
        function getChildSequenceNumber($a_node, $type = "")
        {
                global $ilDB;
                
                if (!isset($a_node))
                {
                        $this->ilErr->raiseError(get_class($this)."::getChildSequenceNumber(): No node_id given! ",$this->ilErr->WARNING);
                }
                
                if($type)
                {
                        $query = 'SELECT count(*) cnt FROM '.$this->table_tree.' '.
                                $this->buildJoin().
                                'WHERE lft <= %s '.
                                'AND type = %s '.
                                'AND parent = %s '.
                                'AND '.$this->table_tree.'.'.$this->tree_pk.' = %s ';
 
                        $res = $ilDB->queryF($query,array('integer','text','integer','integer'),array(
                                $a_node['lft'],
                                $type,
                                $a_node['parent'],
                                $this->tree_id));
                }
                else
                {
                        $query = 'SELECT count(*) cnt FROM '.$this->table_tree.' '.
                                $this->buildJoin().
                                'WHERE lft <= %s '.
                                'AND parent = %s '.
                                'AND '.$this->table_tree.'.'.$this->tree_pk.' = %s ';
 
                        $res = $ilDB->queryF($query,array('integer','integer','integer'),array(
                                $a_node['lft'],
                                $a_node['parent'],
                                $this->tree_id));
                        
                }
                $row = $ilDB->fetchAssoc($res);
                return $row["cnt"];
        }
 
        function readRootId()
        {
                global $ilDB;
                
                $query = 'SELECT child FROM '.$this->table_tree.' '.
                        'WHERE parent = %s '.
                        'AND '.$this->tree_pk.' = %s ';
                $res = $ilDB->queryF($query,array('integer','integer'),array(
                        0,
                        $this->tree_id));
                $row = $ilDB->fetchObject($res);
                $this->root_id = $row->child;
                return $this->root_id;
        }
 
        function getRootId()
        {
                return $this->root_id;
        }
        function setRootId($a_root_id)
        {
                $this->root_id = $a_root_id;
        }
 
        function getTreeId()
        {
                return $this->tree_id;
        }
 
        function setTreeId($a_tree_id)
        {
                $this->tree_id = $a_tree_id;
        }
 
        function fetchSuccessorNode($a_node_id, $a_type = "")
        {
                global $ilDB;
                
                if (!isset($a_node_id))
                {
                        $this->ilErr->raiseError(get_class($this)."::getNodeData(): No node_id given! ",$this->ilErr->WARNING);
                }
 
                // get lft value for current node
                $query = 'SELECT lft FROM '.$this->table_tree.' '.
                        'WHERE '.$this->table_tree.'.child = %s '.
                        'AND '.$this->table_tree.'.'.$this->tree_pk.' = %s ';
                $res = $ilDB->queryF($query,array('integer','integer'),array(
                        $a_node_id,
                        $this->tree_id));
                $curr_node = $ilDB->fetchAssoc($res);
                
                if($a_type)
                {
                        $query = 'SELECT * FROM '.$this->table_tree.' '.
                                $this->buildJoin().
                                'WHERE lft > %s '.
                                'AND '.$this->table_obj_data.'.type = %s '.
                                'AND '.$this->table_tree.'.'.$this->tree_pk.' = %s '.
                                'ORDER BY lft ';
                        $ilDB->setLimit(1);
                        $res = $ilDB->queryF($query,array('integer','text','integer'),array(
                                $curr_node['lft'],
                                $a_type,
                                $this->tree_id));
                }
                else
                {
                        $query = 'SELECT * FROM '.$this->table_tree.' '.
                                $this->buildJoin().
                                'WHERE lft > %s '.
                                'AND '.$this->table_tree.'.'.$this->tree_pk.' = %s '.
                                'ORDER BY lft ';
                        $ilDB->setLimit(1);
                        $res = $ilDB->queryF($query,array('integer','integer'),array(
                                $curr_node['lft'],
                                $this->tree_id));
                }
 
                if ($res->numRows() < 1)
                {
                        return false;
                }
                else
                {
                        $row = $ilDB->fetchAssoc($res);
                        return $this->fetchNodeData($row);
                }
        }
 
        function fetchPredecessorNode($a_node_id, $a_type = "")
        {
                global $ilDB;
                
                if (!isset($a_node_id))
                {
                        $this->ilErr->raiseError(get_class($this)."::getNodeData(): No node_id given! ",$this->ilErr->WARNING);
                }
 
                // get lft value for current node
                $query = 'SELECT lft FROM '.$this->table_tree.' '.
                        'WHERE '.$this->table_tree.'.child = %s '.
                        'AND '.$this->table_tree.'.'.$this->tree_pk.' = %s ';
                $res = $ilDB->queryF($query,array('integer','integer'),array(
                        $a_node_id,
                        $this->tree_id));
 
                $curr_node = $ilDB->fetchAssoc($res);
                
                if($a_type)
                {
                        $query = 'SELECT * FROM '.$this->table_tree.' '.
                                $this->buildJoin().
                                'WHERE lft < %s '.
                                'AND '.$this->table_obj_data.'.type = %s '.
                                'AND '.$this->table_tree.'.'.$this->tree_pk.' = %s '.
                                'ORDER BY lft DESC';
                        $ilDB->setLimit(1);
                        $res = $ilDB->queryF($query,array('integer','text','integer'),array(
                                $curr_node['lft'],
                                $a_type,
                                $this->tree_id));
                }
                else
                {
                        $query = 'SELECT * FROM '.$this->table_tree.' '.
                                $this->buildJoin().
                                'WHERE lft < %s '.
                                'AND '.$this->table_tree.'.'.$this->tree_pk.' = %s '.
                                'ORDER BY lft DESC';
                        $ilDB->setLimit(1);
                        $res = $ilDB->queryF($query,array('integer','integer'),array(
                                $curr_node['lft'],
                                $this->tree_id));
                }
                
                if ($res->numRows() < 1)
                {
                        return false;
                }
                else
                {
                        $row = $ilDB->fetchAssoc($res);
                        return $this->fetchNodeData($row);
                }
        }
 
        function renumber($node_id = 1, $i = 1)
        {
                global $ilDB;
                
                // LOCKED ###################################
                if($this->__isMainTree())
                {
                        /*
                        ilDB::_lockTables(array($this->table_tree => 'WRITE',
                                                                         $this->table_obj_data => 'WRITE',
                                                                         $this->table_obj_reference => 'WRITE',
                                                                         'object_translation' => 'WRITE',
                                                                         'object_data od' => 'WRITE',
                                                                         'container_reference cr' => 'WRITE'));
                        */      
                        $ilDB->lockTables(
                                array(                  
                                        0 => array('name' => $this->table_tree, 'type' => ilDB::LOCK_WRITE),
                                        1 => array('name' => $this->table_obj_data, 'type' => ilDB::LOCK_WRITE),
                                        2 => array('name' => $this->table_obj_reference, 'type' => ilDB::LOCK_WRITE),
                                        3 => array('name' => 'object_translation', 'type' => ilDB::LOCK_WRITE),
                                        4 => array('name' => 'object_data', 'type' => ilDB::LOCK_WRITE, 'alias' => 'od'),
                                        5 => array('name' => 'container_reference', 'type' => ilDB::LOCK_WRITE, 'alias' => 'cr')
                                ));
                }
                $return = $this->__renumber($node_id,$i);
                if($this->__isMainTree())
                {
                        $ilDB->unlockTables();
                }
                // LOCKED ###################################
                return $return;
        }
 
        // PRIVATE
        function __renumber($node_id = 1, $i = 1)
        {
                global $ilDB;
                
                $query = 'UPDATE '.$this->table_tree.' SET lft = %s WHERE child = %s';
                $res = $ilDB->manipulateF($query,array('integer','integer'),array(
                        $i,
                        $node_id));
 
                $childs = $this->getChilds($node_id);
 
                foreach ($childs as $child)
                {
                        $i = $this->__renumber($child["child"],$i+1);
                }
                $i++;
                
                // Insert a gap at the end of node, if the node has children
                if (count($childs) > 0)
                {
                        $i += $this->gap * 2;
                }
                
                
                $query = 'UPDATE '.$this->table_tree.' SET rgt = %s WHERE child = %s';
                $res = $ilDB->manipulateF($query,array('integer','integer'),array(
                        $i,
                        $node_id));
                return $i;
        }
 
 
        function checkForParentType($a_ref_id,$a_type,$a_exclude_source_check = false)
        {                               
                // #12577
                $cache_key = $a_ref_id.'.'.$a_type.'.'.((int)$a_exclude_source_check);
                
                // Try to return a cached result
                if($this->isCacheUsed() &&
                        array_key_exists($cache_key, $this->parent_type_cache)) 
                {                       
                        return $this->parent_type_cache[$cache_key];
                }
                
                // Store up to 1000 results in cache
                $do_cache = ($this->__isMainTree() && count($this->parent_type_cache) < 1000);
 
                // ref_id is not in tree
                if(!$this->isInTree($a_ref_id))
                {
            if($do_cache) 
                        {
                $this->parent_type_cache[$cache_key] = false;
            }
                        return false;
                }
                
                $path = array_reverse($this->getPathFull($a_ref_id));
 
                // remove first path entry as it is requested node
                if($a_exclude_source_check)
                {
                        array_shift($path);
                }
 
                foreach($path as $node)
                {
                        // found matching parent
                        if($node["type"] == $a_type)
                        {
                                if($do_cache) 
                                {
                                        $this->parent_type_cache[$cache_key] = $node["child"];
                                }
                                return $node["child"];
                        }
                }
                
                if($do_cache)
                {
                        $this->parent_type_cache[$cache_key] = false;
                }
                return 0;
        }
 
        function _removeEntry($a_tree,$a_child,$a_db_table = "tree")
        {
                global $ilDB,$ilLog,$ilErr;
 
                if($a_db_table === 'tree')
                {
                        if($a_tree == 1 and $a_child == ROOT_FOLDER_ID)
                        {
                                $message = sprintf('%s::_removeEntry(): Tried to delete root node! $a_tree: %s $a_child: %s',
                                                                   get_class($this),
                                                                   $a_tree,
                                                                   $a_child);
                                $ilLog->write($message,$ilLog->FATAL);
                                $ilErr->raiseError($message,$ilErr->WARNING);
                        }
                }
                
                $query = 'DELETE FROM '.$a_db_table.' '.
                        'WHERE tree = %s '.
                        'AND child = %s ';
                $res = $ilDB->manipulateF($query,array('integer','integer'),array(
                        $a_tree,
                        $a_child));
                
        }
        
        public function __isMainTree()
        {
                return $this->table_tree === 'tree';
        }
 
        function __checkDelete($a_node)
        {
                global $ilDB;
                
                
                $query = $this->getTreeImplementation()->getSubTreeQuery($a_node, array(),false);
                $GLOBALS['ilLog']->write(__METHOD__.': '.$query);
                $res = $ilDB->query($query);
                
                $counter = (int) $lft_childs = array();
                while($row = $ilDB->fetchObject($res))
                {
                        $lft_childs[$row->child] = $row->parent;
                        ++$counter;
                }
 
                // CHECK FOR DUPLICATE CHILD IDS
                if($counter != count($lft_childs))
                {
                        $message = sprintf('%s::__checkTree(): Duplicate entries for "child" in maintree! $a_node_id: %s',
                                                                   get_class($this),
                                                           $a_node['child']);
                        $this->log->write($message,$this->log->FATAL);
                        $this->ilErr->raiseError($message,$this->ilErr->WARNING);
                }
 
                // GET SUBTREE BY PARENT RELATION
                $parent_childs = array();
                $this->__getSubTreeByParentRelation($a_node['child'],$parent_childs);
                $this->__validateSubtrees($lft_childs,$parent_childs);
 
                return true;
        }
 
        function __getSubTreeByParentRelation($a_node_id,&$parent_childs)
        {
                global $ilDB;
                
                // GET PARENT ID
                $query = 'SELECT * FROM '.$this->table_tree.' '.
                        'WHERE child = %s '.
                        'AND tree = %s ';
                $res = $ilDB->queryF($query,array('integer','integer'),array(
                        $a_node_id,
                        $this->tree_id));
 
                $counter = 0;
                while($row = $ilDB->fetchObject($res))
                {
                        $parent_childs[$a_node_id] = $row->parent;
                        ++$counter;
                }
                // MULTIPLE ENTRIES
                if($counter > 1)
                {
                        $message = sprintf('%s::__getSubTreeByParentRelation(): Multiple entries in maintree! $a_node_id: %s',
                                                           get_class($this),
                                                           $a_node_id);
                        $this->log->write($message,$this->log->FATAL);
                        $this->ilErr->raiseError($message,$this->ilErr->WARNING);
                }
 
                // GET ALL CHILDS
                $query = 'SELECT * FROM '.$this->table_tree.' '.
                        'WHERE parent = %s ';
                $res = $ilDB->queryF($query,array('integer'),array($a_node_id));
 
                while($row = $ilDB->fetchObject($res))
                {
                        // RECURSION
                        $this->__getSubTreeByParentRelation($row->child,$parent_childs);
                }
                return true;
        }
 
        function __validateSubtrees(&$lft_childs,$parent_childs)
        {
                // SORT BY KEY
                ksort($lft_childs);
                ksort($parent_childs);
 
                $GLOBALS['ilLog']->write(__METHOD__.': left childs '. print_r($lft_childs,true));
                $GLOBALS['ilLog']->write(__METHOD__.': parent childs '. print_r($parent_childs,true));
 
                if(count($lft_childs) != count($parent_childs))
                {
                        $message = sprintf('%s::__validateSubtrees(): (COUNT) Tree is corrupted! Left/Right subtree does not comply .'.
                                                           'with parent relation',
                                                           get_class($this));
                        $this->log->write($message,$this->log->FATAL);
                        $this->ilErr->raiseError($message,$this->ilErr->WARNING);
                }
                
 
                foreach($lft_childs as $key => $value)
                {
                        if($parent_childs[$key] != $value)
                        {
                                $message = sprintf('%s::__validateSubtrees(): (COMPARE) Tree is corrupted! Left/Right subtree does not comply '.
                                                                   'with parent relation',
                                                                   get_class($this));
                                $this->log->write($message,$this->log->FATAL);
                                $this->ilErr->raiseError($message,$this->ilErr->WARNING);
                        }
                        if($key == ROOT_FOLDER_ID)
                        {
                                $message = sprintf('%s::__validateSubtrees(): (ROOT_FOLDER) Tree is corrupted! Tried to delete root folder',
                                                                   get_class($this));
                                $this->log->write($message,$this->log->FATAL);
                                $this->ilErr->raiseError($message,$this->ilErr->WARNING);
                        }
                }
                return true;
        }
        
        public function moveTree($a_source_id, $a_target_id, $a_location = self::POS_LAST_NODE)
        {
                $this->getTreeImplementation()->moveTree($a_source_id,$a_target_id,$a_location);
                $GLOBALS['ilAppEventHandler']->raise(
                                "Services/Tree", 
                                "moveTree", 
                                array(
                                        'tree'          => $this->table_tree,
                                        'source_id' => $a_source_id, 
                                        'target_id' => $a_target_id)
                );
                return true;
        }
        
        
        
        
        public function getRbacSubtreeInfo($a_endnode_id)
        {
                return $this->getTreeImplementation()->getSubtreeInfo($a_endnode_id);
        }
        
 
        public function getSubTreeQuery($a_node_id,$a_fields = array(), $a_types = '', $a_force_join_reference = false)
        {
                return $this->getTreeImplementation()->getSubTreeQuery(
                                $this->getNodeTreeData($a_node_id),
                                $a_types, 
                                $a_force_join_reference, 
                                $a_fields);
        }
        
        
        public function getSubTreeFilteredByObjIds($a_node_id, array $a_obj_ids, array $a_fields = array())
        {
                global $ilDB;
                
                $node = $this->getNodeData($a_node_id);
                if(!sizeof($node))
                {
                        return;
                }
                
                $res = array();
                
                $query = $this->getTreeImplementation()->getSubTreeQuery($node, '', true, array($this->ref_pk));
                
                $fields = '*';
                if(count($a_fields))
                {
                        $fields = implode(',',$a_fields);
                }
                
                $query = "SELECT ".$fields.
                        " FROM ".$this->getTreeTable().
                        " ".$this->buildJoin().
                        " WHERE ".$this->getTableReference().".".$this->ref_pk." IN (".$query.")".
                        " AND ".$ilDB->in($this->getObjectDataTable().".".$this->obj_pk, $a_obj_ids, "", "integer");
                $set = $ilDB->query($query);
                while($row = $ilDB->fetchAssoc($set))
                {
                        $res[] = $row;
                }
                
                return $res;
        }
        
        public function deleteNode($a_tree_id,$a_node_id)
        {
                global $ilDB;
                
                $query = 'DELETE FROM tree where '.
                                'child = '.$ilDB->quote($a_node_id,'integer').' '.
                                'AND tree = '.$ilDB->quote($a_tree_id,'integer');
                $ilDB->manipulate($query);
        }
        
        
} // END class.tree
?>