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