/*
* Copyright 2006-2007 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.batch.repeat.context;
import java.util.concurrent.atomic.AtomicInteger;
import org.springframework.batch.repeat.RepeatContext;
import org.springframework.util.Assert;
/**
* Helper class for policies that need to count the number of occurrences of
* some event (e.g. an exception type in the context) in the scope of a batch.
* The value of the counter can be stored between batches in a nested context,
* so that the termination decision is based on the aggregate of a number of
* sibling batches.
*
* @author Dave Syer
*
*/
public class RepeatContextCounter {
final private String countKey;
/**
* Flag to indicate whether the count is stored at the level of the parent
* context, or just local to the current context. Default value is false.
*/
final private boolean useParent;
final private RepeatContext context;
/**
* Increment the counter.
*
* @param delta the amount by which to increment the counter.
*/
final public void increment(int delta) {
AtomicInteger count = getCounter();
count.addAndGet(delta);
}
/**
* Increment by 1.
*/
final public void increment() {
increment(1);
}
/**
* Convenience constructor with useParent=false.
* @param context the current context.
* @param countKey the key to use to store the counter in the context.
*/
public RepeatContextCounter(RepeatContext context, String countKey) {
this(context, countKey, false);
}
/**
* Construct a new {@link RepeatContextCounter}.
*
* @param context the current context.
* @param countKey the key to use to store the counter in the context.
* @param useParent true if the counter is to be shared between siblings.
* The state will be stored in the parent of the context (if it exists)
* instead of the context itself.
*/
public RepeatContextCounter(RepeatContext context, String countKey, boolean useParent) {
super();
Assert.notNull(context, "The context must be provided to initialize a counter");
this.countKey = countKey;
this.useParent = useParent;
RepeatContext parent = context.getParent();
if (this.useParent && parent != null) {
this.context = parent;
}
else {
this.context = context;
}
if (!this.context.hasAttribute(countKey)) {
this.context.setAttribute(countKey, new AtomicInteger());
}
}
/**
* @return the current value of the counter
*/
public int getCount() {
return getCounter().intValue();
}
private AtomicInteger getCounter() {
return ((AtomicInteger) context.getAttribute(countKey));
}
}