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     */
020    package org.apache.directory.server.xdbm.search.impl;
021    
022    
023    import javax.naming.NamingException;
024    
025    import org.apache.directory.shared.ldap.filter.BranchNode;
026    import org.apache.directory.shared.ldap.filter.ExprNode;
027    import 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     * @version $Rev$, $Date$
037     */
038    public class NoOpOptimizer implements Optimizer
039    {
040        /** the maximum size for a count Integer.MAX_VALUE as a BigInteger */
041        private static final Long MAX = Long.MAX_VALUE;
042    
043    
044        public Long annotate( ExprNode node ) throws NamingException
045        {
046            if ( node.isLeaf() )
047            {
048                node.set( "count", MAX );
049                return MAX;
050            }
051    
052            BranchNode bnode = ( BranchNode ) node;
053            if ( bnode.getChildren().size() == 0 )
054            {
055                bnode.set( "count", MAX );
056                return MAX;
057            }
058    
059            final int limit = bnode.getChildren().size();
060            for ( int ii = 0; ii < limit; ii++ )
061            {
062                ExprNode child = bnode.getChildren().get( ii );
063                if ( child.isLeaf() )
064                {
065                    child.set( "count", MAX );
066                }
067                else
068                {
069                    annotate( child );
070                }
071            }
072    
073            bnode.set( "count", MAX );
074            return MAX;
075        }
076    }