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.shared.ldap.cursor;
020    
021    import org.apache.directory.shared.i18n.I18n;
022    
023    
024    /**
025     * An empty Cursor implementation.
026     *
027     * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
028     * @version $Rev$, $Date$
029     */
030    public class EmptyCursor<E> extends AbstractCursor<E>
031    {
032        /**
033         * {@inheritDoc}
034         */
035        public boolean available()
036        {
037            return false;
038        }
039    
040        /**
041         * {@inheritDoc}
042         */
043        public void before( E element ) throws Exception
044        {
045            checkNotClosed( "before()" );
046        }
047    
048    
049        /**
050         * {@inheritDoc}
051         */
052        public void after( E element ) throws Exception
053        {
054            checkNotClosed( "after()" );
055        }
056    
057    
058        /**
059         * {@inheritDoc}
060         */
061        public void beforeFirst() throws Exception
062        {
063            checkNotClosed( "beforeFirst()" );
064        }
065    
066    
067        /**
068         * {@inheritDoc}
069         */
070        public void afterLast() throws Exception
071        {
072            checkNotClosed( "afterLast()" );
073        }
074    
075    
076        /**
077         * {@inheritDoc}
078         */
079        public boolean first() throws Exception
080        {
081            checkNotClosed( "first()" );
082            return false;
083        }
084    
085    
086        /**
087         * {@inheritDoc}
088         */
089        public boolean last() throws Exception
090        {
091            checkNotClosed( "last()" );
092            return false;
093        }
094    
095    
096        /**
097         * {@inheritDoc}
098         */
099        public boolean previous() throws Exception
100        {
101            checkNotClosed( "previous()" );
102            return false;
103        }
104    
105    
106        /**
107         * {@inheritDoc}
108         */
109        public boolean next() throws Exception
110        {
111            checkNotClosed( "next()" );
112            return false;
113        }
114    
115    
116        /**
117         * {@inheritDoc}
118         */
119        public E get() throws Exception
120        {
121            checkNotClosed( "get()" );
122            throw new InvalidCursorPositionException( I18n.err( I18n.ERR_02004 ) );
123        }
124    
125    
126        /**
127         * {@inheritDoc}
128         */
129        public boolean isElementReused()
130        {
131            return false;
132        }
133    }