1 /*
2 * Copyright 2006-2007 the original author or authors.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package org.springframework.batch.repeat.policy;
18
19 import org.springframework.batch.repeat.RepeatStatus;
20 import org.springframework.batch.repeat.RepeatContext;
21 import org.springframework.batch.repeat.context.RepeatContextSupport;
22 import org.springframework.batch.repeat.support.RepeatTemplate;
23 import org.springframework.util.ClassUtils;
24
25 /**
26 * Policy for terminating a batch after a fixed number of operations. Internal
27 * state is maintained and a counter incremented, so successful use of this
28 * policy requires that isComplete() is only called once per batch item. Using
29 * the standard {@link RepeatTemplate} should ensure this contract is kept, but it needs
30 * to be carefully monitored.
31 *
32 * @author Dave Syer
33 *
34 */
35 public class SimpleCompletionPolicy extends DefaultResultCompletionPolicy {
36
37 public static final int DEFAULT_CHUNK_SIZE = 5;
38
39 int chunkSize = 0;
40
41 public SimpleCompletionPolicy() {
42 this(DEFAULT_CHUNK_SIZE);
43 }
44
45 public SimpleCompletionPolicy(int chunkSize) {
46 super();
47 this.chunkSize = chunkSize;
48 }
49
50 public void setChunkSize(int chunkSize) {
51 this.chunkSize = chunkSize;
52 }
53
54 /**
55 * Reset the counter.
56 *
57 * @see org.springframework.batch.repeat.CompletionPolicy#start(RepeatContext)
58 */
59 @Override
60 public RepeatContext start(RepeatContext context) {
61 return new SimpleTerminationContext(context);
62 }
63
64 /**
65 * Terminate if the chunk size has been reached, or the result is null.
66 *
67 * @see org.springframework.batch.repeat.CompletionPolicy#isComplete(RepeatContext,
68 * RepeatStatus)
69 * @throws RuntimeException (normally terminating the batch) if the result is
70 * itself an exception.
71 */
72 @Override
73 public boolean isComplete(RepeatContext context, RepeatStatus result) {
74 return super.isComplete(context, result) || ((SimpleTerminationContext) context).isComplete();
75 }
76
77 /**
78 * Terminate if the chunk size has been reached.
79 *
80 * @see org.springframework.batch.repeat.CompletionPolicy#isComplete(RepeatContext)
81 */
82 @Override
83 public boolean isComplete(RepeatContext context) {
84 return ((SimpleTerminationContext) context).isComplete();
85 }
86
87 /**
88 * Increment the counter in the context.
89 *
90 * @see org.springframework.batch.repeat.CompletionPolicy#update(RepeatContext)
91 */
92 @Override
93 public void update(RepeatContext context) {
94 ((SimpleTerminationContext) context).update();
95 }
96
97 protected class SimpleTerminationContext extends RepeatContextSupport {
98
99 public SimpleTerminationContext(RepeatContext context) {
100 super(context);
101 }
102
103 public void update() {
104 increment();
105 }
106
107 public boolean isComplete() {
108 return getStartedCount() >= chunkSize;
109 }
110 }
111
112 /* (non-Javadoc)
113 * @see java.lang.Object#toString()
114 */
115 @Override
116 public String toString() {
117 return ClassUtils.getShortName(SimpleCompletionPolicy.class)+": chunkSize="+chunkSize;
118 }
119
120 }