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 */
019package org.apache.directory.shared.ldap.model.cursor;
020
021
022import org.apache.directory.shared.i18n.I18n;
023
024
025/**
026 * An empty Cursor implementation.
027 *
028 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
029 * @param <E> The type of element on which this cursor will iterate
030 */
031public class EmptyCursor<E> extends AbstractCursor<E>
032{
033    /**
034     * {@inheritDoc}
035     */
036    public boolean available()
037    {
038        return false;
039    }
040
041
042    /**
043     * {@inheritDoc}
044     */
045    public void before( E element ) throws Exception
046    {
047        checkNotClosed( "before()" );
048    }
049
050
051    /**
052     * {@inheritDoc}
053     */
054    public void after( E element ) throws Exception
055    {
056        checkNotClosed( "after()" );
057    }
058
059
060    /**
061     * {@inheritDoc}
062     */
063    public void beforeFirst() throws Exception
064    {
065        checkNotClosed( "beforeFirst()" );
066    }
067
068
069    /**
070     * {@inheritDoc}
071     */
072    public void afterLast() throws Exception
073    {
074        checkNotClosed( "afterLast()" );
075    }
076
077
078    /**
079     * {@inheritDoc}
080     */
081    public boolean first() throws Exception
082    {
083        checkNotClosed( "first()" );
084        return false;
085    }
086
087
088    /**
089     * {@inheritDoc}
090     */
091    public boolean last() throws Exception
092    {
093        checkNotClosed( "last()" );
094        return false;
095    }
096
097
098    /**
099     * {@inheritDoc}
100     */
101    public boolean previous() throws Exception
102    {
103        checkNotClosed( "previous()" );
104        return false;
105    }
106
107
108    /**
109     * {@inheritDoc}
110     */
111    public boolean next() throws Exception
112    {
113        checkNotClosed( "next()" );
114        return false;
115    }
116
117
118    /**
119     * {@inheritDoc}
120     */
121    public E get() throws Exception
122    {
123        checkNotClosed( "get()" );
124        throw new InvalidCursorPositionException( I18n.err( I18n.ERR_02004_EMPTY_CURSOR ) );
125    }
126}