old_trunk/btree-base/src/main/java/org/apache/directory/server/core/partition/impl/btree/IndexRecord.java

/*
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
 *  with the License.  You may obtain a copy of the License at
 *  
 *    http://www.apache.org/licenses/LICENSE-2.0
 *  
 *  Unless required by applicable law or agreed to in writing,
 *  software distributed under the License is distributed on an
 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 *  KIND, either express or implied.  See the License for the
 *  specific language governing permissions and limitations
 *  under the License. 
 *  
 */
package org.apache.directory.server.core.partition.impl.btree;

import org.apache.directory.server.core.entry.ServerEntry;


/**
 * An index key value pair based on a tuple which can optionally reference the
 * indexed entry if one has been resusitated.
 * 
 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
 * @version $Rev$
 */
public class IndexRecord
{
    /** The underlying BTree Tuple */
    private final Tuple tuple = new Tuple();
    
    /** The referenced entry if ressucitated */
    private ServerEntry entry = null;


    /**
     * Sets the key value tuple represented by this IndexRecord optionally 
     * setting the entry if one was resusitated from the master table.
     *
     * @param tuple the tuple for the IndexRecord
     * @param entry the resusitated entry if any
     */
    public void setTuple( Tuple tuple, ServerEntry entry )
    {
        this.tuple.setKey( tuple.getKey() );
        this.tuple.setValue( tuple.getValue() );
        this.entry = entry;
    }


    /**
     * Sets the key value tuple but swapping the key and the value and 
     * optionally adding the entry if one was resusitated.
     *
     * @param tuple the tuple for the IndexRecord
     * @param entry the resusitated entry if any
     */
    public void setSwapped( Tuple tuple, ServerEntry entry )
    {
        this.tuple.setKey( tuple.getValue() );
        this.tuple.setValue( tuple.getKey() );
        this.entry = entry;
    }


    /**
     * Gets the entry id for this IndexRecord. 
     *
     * @return the id of the entry indexed
     */
    public Object getEntryId()
    {
        return tuple.getValue();
    }


    /**
     * Gets the index key ( the attribute's value ) for this IndexRecord.
     *
     * @return the key of the entry indexed
     */
    public Object getIndexKey()
    {
        return tuple.getKey();
    }


    /**
     * Sets the entry id.
     *
     * @param id the id of the entry
     */
    public void setEntryId( Object id )
    {
        tuple.setValue( id );
    }


    /**
     * Sets the index key.
     *
     * @param key the key of the IndexRecord
     */
    public void setIndexKey( Object key )
    {
        tuple.setKey( key );
    }


    /**
     * Gets the entry of this IndexRecord if one was resusitated form the master
     * table.
     * 
     * @return the entry's attributes
     */
    public ServerEntry getEntry()
    {
        if ( entry == null )
        {
            return null;
        }

        return ( ServerEntry ) entry.clone();
    }


    /**
     * Sets the entry's attributes.
     * 
     * @param entry the entry's attributes
     */
    public void setEntry( ServerEntry entry )
    {
        this.entry = entry;
    }


    /**
     * Clears the tuple key, the tuple value and the entry fields.
     */
    public void clear()
    {
        entry = null;
        tuple.setKey( null );
        tuple.setValue( null );
    }


    /**
     * Utility method used to copy the contents of one IndexRecord into this
     * IndexRecord.
     * 
     * @param record the record whose contents we copy
     */
    public void copy( IndexRecord record )
    {
        entry = record.getEntry();
        tuple.setKey( record.getIndexKey() );
        tuple.setValue( record.getEntryId() );
    }
}