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.context;
18
19 import java.util.concurrent.atomic.AtomicInteger;
20
21 import org.springframework.batch.repeat.RepeatContext;
22 import org.springframework.util.Assert;
23
24 /**
25 * Helper class for policies that need to count the number of occurrences of
26 * some event (e.g. an exception type in the context) in the scope of a batch.
27 * The value of the counter can be stored between batches in a nested context,
28 * so that the termination decision is based on the aggregate of a number of
29 * sibling batches.
30 *
31 * @author Dave Syer
32 *
33 */
34 public class RepeatContextCounter {
35
36 final private String countKey;
37
38 /**
39 * Flag to indicate whether the count is stored at the level of the parent
40 * context, or just local to the current context. Default value is false.
41 */
42 final private boolean useParent;
43
44 final private RepeatContext context;
45
46 /**
47 * Increment the counter.
48 *
49 * @param delta the amount by which to increment the counter.
50 */
51 final public void increment(int delta) {
52 AtomicInteger count = getCounter();
53 count.addAndGet(delta);
54 }
55
56 /**
57 * Increment by 1.
58 */
59 final public void increment() {
60 increment(1);
61 }
62
63 /**
64 * Convenience constructor with useParent=false.
65 * @param context the current context.
66 * @param countKey the key to use to store the counter in the context.
67 */
68 public RepeatContextCounter(RepeatContext context, String countKey) {
69 this(context, countKey, false);
70 }
71
72 /**
73 * Construct a new {@link RepeatContextCounter}.
74 *
75 * @param context the current context.
76 * @param countKey the key to use to store the counter in the context.
77 * @param useParent true if the counter is to be shared between siblings.
78 * The state will be stored in the parent of the context (if it exists)
79 * instead of the context itself.
80 */
81 public RepeatContextCounter(RepeatContext context, String countKey, boolean useParent) {
82
83 super();
84
85 Assert.notNull(context, "The context must be provided to initialize a counter");
86
87 this.countKey = countKey;
88 this.useParent = useParent;
89
90 RepeatContext parent = context.getParent();
91
92 if (this.useParent && parent != null) {
93 this.context = parent;
94 }
95 else {
96 this.context = context;
97 }
98 if (!this.context.hasAttribute(countKey)) {
99 this.context.setAttribute(countKey, new AtomicInteger());
100 }
101
102 }
103
104 /**
105 * @return the current value of the counter
106 */
107 public int getCount() {
108 return getCounter().intValue();
109 }
110
111 private AtomicInteger getCounter() {
112 return ((AtomicInteger) context.getAttribute(countKey));
113 }
114
115 }