1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.apache.directory.server.core.cursor;
20
21
22 /**
23 * A Cursor's state: cursor states leverage the State Pattern to isolate state
24 * specific transition logic with certain operations. Not every Cursor is
25 * that complex so the implementor should decide whether or not using the
26 * State Pattern is over kill on a per Cursor implementation basis.
27 *
28 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
29 * @version $Rev$, $Date$
30 */
31 public interface CursorState<E>
32 {
33 void before( E element ) throws Exception;
34
35 void after( E element ) throws Exception;
36
37 void beforeFirst() throws Exception;
38
39 void afterLast() throws Exception;
40
41 boolean first() throws Exception;
42
43 boolean last() throws Exception;
44
45 boolean previous() throws Exception;
46
47 boolean next() throws Exception;
48 }