01: /*
02: * Licensed to the Apache Software Foundation (ASF) under one or more
03: * contributor license agreements. See the NOTICE file distributed with
04: * this work for additional information regarding copyright ownership.
05: * The ASF licenses this file to You under the Apache License, Version 2.0
06: * (the "License"); you may not use this file except in compliance with
07: * the License. You may obtain a copy of the License at
08: *
09: * http://www.apache.org/licenses/LICENSE-2.0
10: *
11: * Unless required by applicable law or agreed to in writing, software
12: * distributed under the License is distributed on an "AS IS" BASIS,
13: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14: * See the License for the specific language governing permissions and
15: * limitations under the License.
16: */
17: package org.apache.commons.betwixt.io.id;
18:
19: import org.apache.commons.betwixt.io.IDGenerator;
20:
21: /** <p>Abstract superclass for {@link IDGenerator} implementations.</p>
22: *
23: * <p>It implements the entire <code>IDGenerator</code> interface.
24: * When <code>nextId</code> is called,
25: * this class sets the <code>LastId</code> property (as well
26: * as returning the value).
27: * Subclasses should override {@link #nextIdImpl}.</p>
28: *
29: * @author <a href="mailto:rdonkin@apache.org">Robert Burrell Donkin</a>
30: * @version $Revision: 438373 $
31: */
32: public abstract class AbstractIDGenerator implements IDGenerator {
33:
34: /** Last <code>ID</code> returned */
35: private String lastId = "0";
36:
37: /**
38: * Gets last <code>ID</code> returned.
39: *
40: * @return the last id created by the generated
41: */
42: public final String getLastId() {
43: return lastId;
44: }
45:
46: /**
47: * <p>Generate next <code>ID</code>.</p>
48: *
49: * <p>This method obtains the next <code>ID</code> from subclass
50: * and then uses this to set the <code>LastId</code> property.</p>
51: *
52: * @return the next id generated
53: */
54: public final String nextId() {
55: lastId = nextIdImpl();
56: return lastId;
57: }
58:
59: /**
60: * Subclasses should <strong>provide an implementation</strong> for this method.
61: * This implementation needs only provide the next <code>ID</code>
62: * value (according to it's algorithm).
63: * Setting the <code>LastId</code> property can be left to this class.
64: *
65: * @return the next id generated
66: */
67: protected abstract String nextIdImpl();
68: }
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