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    package org.apache.directory.server.xdbm;
020    
021    
022    import org.apache.directory.server.i18n.I18n;
023    import org.apache.directory.shared.ldap.cursor.InvalidCursorPositionException;
024    
025    
026    /**
027     * An empty Cursor implementation.
028     *
029     * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
030     * @version $Rev$, $Date$
031     */
032    public class EmptyIndexCursor<K, E, ID> extends AbstractIndexCursor<K, E, ID>
033    {
034        public boolean available()
035        {
036            return false;
037        }
038    
039    
040        public void before( IndexEntry<K, E, ID> element ) throws Exception
041        {
042            checkNotClosed( "before()" );
043        }
044    
045    
046        public void after( IndexEntry<K, E, ID> element ) throws Exception
047        {
048            checkNotClosed( "after()" );
049        }
050    
051    
052        public void beforeFirst() throws Exception
053        {
054            checkNotClosed( "beforeFirst()" );
055        }
056    
057    
058        public void afterLast() throws Exception
059        {
060            checkNotClosed( "afterLast()" );
061        }
062    
063    
064        public boolean first() throws Exception
065        {
066            checkNotClosed( "first()" );
067            return false;
068        }
069    
070    
071        public boolean last() throws Exception
072        {
073            checkNotClosed( "last()" );
074            return false;
075        }
076    
077    
078        public boolean previous() throws Exception
079        {
080            checkNotClosed( "previous()" );
081            return false;
082        }
083    
084    
085        public boolean next() throws Exception
086        {
087            checkNotClosed( "next()" );
088            return false;
089        }
090    
091    
092        public IndexEntry<K, E, ID> get() throws Exception
093        {
094            checkNotClosed( "get()" );
095            throw new InvalidCursorPositionException( I18n.err( I18n.ERR_703 ) );
096        }
097    
098    
099        public boolean isElementReused()
100        {
101            return false;
102        }
103    
104    
105        public void afterValue( ID id, K indexValue ) throws Exception
106        {
107            checkNotClosed( "after()" );
108        }
109    
110    
111        public void beforeValue( ID id, K indexValue ) throws Exception
112        {
113            checkNotClosed( "after()" );
114        }
115    }