001/*
002 *  Licensed to the Apache Software Foundation (ASF) under one
003 *  or more contributor license agreements.  See the NOTICE file
004 *  distributed with this work for additional information
005 *  regarding copyright ownership.  The ASF licenses this file
006 *  to you under the Apache License, Version 2.0 (the
007 *  "License"); you may not use this file except in compliance
008 *  with the License.  You may obtain a copy of the License at
009 *  
010 *    http://www.apache.org/licenses/LICENSE-2.0
011 *  
012 *  Unless required by applicable law or agreed to in writing,
013 *  software distributed under the License is distributed on an
014 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 *  KIND, either express or implied.  See the License for the
016 *  specific language governing permissions and limitations
017 *  under the License. 
018 *  
019 */
020package org.apache.directory.server.xdbm.search.impl;
021
022
023import org.apache.directory.api.ldap.model.exception.LdapException;
024import org.apache.directory.api.ldap.model.filter.BranchNode;
025import org.apache.directory.api.ldap.model.filter.ExprNode;
026import org.apache.directory.server.core.api.partition.PartitionTxn;
027import org.apache.directory.server.xdbm.search.Optimizer;
028
029
030/**
031 * A do nothing optimizer which labels all nodes with <code>
032 * BigInteger.valueOf( Integer.MAX_VALUE ) </code>, instead of actually 
033 * taking scan counts.
034 * 
035 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
036 */
037public class NoOpOptimizer implements Optimizer
038{
039    /** the maximum size for a count Integer.MAX_VALUE as a BigInteger */
040    private static final Long MAX = Long.MAX_VALUE;
041
042
043    public Long annotate( PartitionTxn partitionTxn, ExprNode node ) throws LdapException
044    {
045        if ( node.isLeaf() )
046        {
047            node.set( "count", MAX );
048            return MAX;
049        }
050
051        BranchNode bnode = ( BranchNode ) node;
052        if ( bnode.getChildren().size() == 0 )
053        {
054            bnode.set( "count", MAX );
055            return MAX;
056        }
057
058        final int limit = bnode.getChildren().size();
059        for ( int ii = 0; ii < limit; ii++ )
060        {
061            ExprNode child = bnode.getChildren().get( ii );
062            if ( child.isLeaf() )
063            {
064                child.set( "count", MAX );
065            }
066            else
067            {
068                annotate( partitionTxn, child );
069            }
070        }
071
072        bnode.set( "count", MAX );
073        return MAX;
074    }
075}