/*
* Copyright 2012-2013 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.core.step.builder;
import java.util.LinkedHashSet;
import java.util.Set;
import org.springframework.batch.core.ChunkListener;
import org.springframework.batch.core.Step;
import org.springframework.batch.core.StepExecutionListener;
import org.springframework.batch.core.step.tasklet.Tasklet;
import org.springframework.batch.core.step.tasklet.TaskletStep;
import org.springframework.batch.item.ItemStream;
import org.springframework.batch.repeat.RepeatOperations;
import org.springframework.batch.repeat.exception.DefaultExceptionHandler;
import org.springframework.batch.repeat.exception.ExceptionHandler;
import org.springframework.batch.repeat.support.RepeatTemplate;
import org.springframework.batch.repeat.support.TaskExecutorRepeatTemplate;
import org.springframework.core.task.SyncTaskExecutor;
import org.springframework.core.task.TaskExecutor;
import org.springframework.transaction.interceptor.TransactionAttribute;
/**
* Base class for step builders that want to build a {@link TaskletStep}. Handles common concerns across all tasklet
* step variants, which are mostly to do with the type of tasklet they carry.
*
* @author Dave Syer
* @author Michael Minella
*
* @since 2.2
*
* @param <B> the type of builder represented
*/
public abstract class AbstractTaskletStepBuilder<B extends AbstractTaskletStepBuilder<B>> extends
StepBuilderHelper<AbstractTaskletStepBuilder<B>> {
protected Set<ChunkListener> chunkListeners = new LinkedHashSet<ChunkListener>();
private RepeatOperations stepOperations;
private TransactionAttribute transactionAttribute;
private Set<ItemStream> streams = new LinkedHashSet<ItemStream>();
private ExceptionHandler exceptionHandler = new DefaultExceptionHandler();
private int throttleLimit = TaskExecutorRepeatTemplate.DEFAULT_THROTTLE_LIMIT;
private TaskExecutor taskExecutor;
public AbstractTaskletStepBuilder(StepBuilderHelper<?> parent) {
super(parent);
}
protected abstract Tasklet createTasklet();
/**
* Build the step from the components collected by the fluent setters. Delegates first to {@link #enhance(Step)} and
* then to {@link #createTasklet()} in subclasses to create the actual tasklet.
*
* @return a tasklet step fully configured and read to execute
*/
public TaskletStep build() {
registerStepListenerAsChunkListener();
TaskletStep step = new TaskletStep(getName());
super.enhance(step);
step.setChunkListeners(chunkListeners.toArray(new ChunkListener[0]));
if (transactionAttribute != null) {
step.setTransactionAttribute(transactionAttribute);
}
if (stepOperations == null) {
stepOperations = new RepeatTemplate();
if (taskExecutor != null) {
TaskExecutorRepeatTemplate repeatTemplate = new TaskExecutorRepeatTemplate();
repeatTemplate.setTaskExecutor(taskExecutor);
repeatTemplate.setThrottleLimit(throttleLimit);
stepOperations = repeatTemplate;
}
((RepeatTemplate) stepOperations).setExceptionHandler(exceptionHandler);
}
step.setStepOperations(stepOperations);
step.setTasklet(createTasklet());
step.setStreams(streams.toArray(new ItemStream[0]));
try {
step.afterPropertiesSet();
}
catch (Exception e) {
throw new StepBuilderException(e);
}
return step;
}
protected void registerStepListenerAsChunkListener() {
for (StepExecutionListener stepExecutionListener: properties.getStepExecutionListeners()){
if (stepExecutionListener instanceof ChunkListener){
listener((ChunkListener)stepExecutionListener);
}
}
}
/**
* Register a chunk listener.
*
* @param listener the listener to register
* @return this for fluent chaining
*/
public AbstractTaskletStepBuilder<B> listener(ChunkListener listener) {
chunkListeners.add(listener);
return this;
}
/**
* Register a stream for callbacks that manage restart data.
*
* @param stream the stream to register
* @return this for fluent chaining
*/
public AbstractTaskletStepBuilder<B> stream(ItemStream stream) {
streams.add(stream);
return this;
}
/**
* Provide a task executor to use when executing the tasklet. Default is to use a single-threaded (synchronous)
* executor.
*
* @param taskExecutor the task executor to register
* @return this for fluent chaining
*/
public AbstractTaskletStepBuilder<B> taskExecutor(TaskExecutor taskExecutor) {
this.taskExecutor = taskExecutor;
return this;
}
/**
* In the case of an asynchronous {@link #taskExecutor(TaskExecutor)} the number of concurrent tasklet executions
* can be throttled (beyond any throttling provided by a thread pool). The throttle limit should be less than the
* data source pool size used in the job repository for this step.
*
* @param throttleLimit maximum number of concurrent tasklet executions allowed
* @return this for fluent chaining
*/
public AbstractTaskletStepBuilder<B> throttleLimit(int throttleLimit) {
this.throttleLimit = throttleLimit;
return this;
}
/**
* Sets the exception handler to use in the case of tasklet failures. Default is to rethrow everything.
*
* @param exceptionHandler the exception handler
* @return this for fluent chaining
*/
public AbstractTaskletStepBuilder<B> exceptionHandler(ExceptionHandler exceptionHandler) {
this.exceptionHandler = exceptionHandler;
return this;
}
/**
* Sets the repeat template used for iterating the tasklet execution. By default it will terminate only when the
* tasklet returns FINISHED (or null).
*
* @param repeatTemplate a repeat template with rules for iterating
* @return this for fluent chaining
*/
public AbstractTaskletStepBuilder<B> stepOperations(RepeatOperations repeatTemplate) {
this.stepOperations = repeatTemplate;
return this;
}
/**
* Sets the transaction attributes for the tasklet execution. Defaults to the default values for the transaction
* manager, but can be manipulated to provide longer timeouts for instance.
*
* @param transactionAttribute a transaction attribute set
* @return this for fluent chaining
*/
public AbstractTaskletStepBuilder<B> transactionAttribute(TransactionAttribute transactionAttribute) {
this.transactionAttribute = transactionAttribute;
return this;
}
/**
* Convenience method for subclasses to access the step operations that were injected by user.
*
* @return the repeat operations used to iterate the tasklet executions
*/
protected RepeatOperations getStepOperations() {
return stepOperations;
}
/**
* Convenience method for subclasses to access the exception handler that was injected by user.
*
* @return the exception handler
*/
protected ExceptionHandler getExceptionHandler() {
return exceptionHandler;
}
/**
* Convenience method for subclasses to determine if the step is concurrent.
*
* @return true if the tasklet is going to be run in multiple threads
*/
protected boolean concurrent() {
boolean concurrent = taskExecutor != null && !(taskExecutor instanceof SyncTaskExecutor);
return concurrent;
}
protected TaskExecutor getTaskExecutor() {
return taskExecutor;
}
protected int getThrottleLimit() {
return throttleLimit;
}
protected TransactionAttribute getTransactionAttribute() {
return transactionAttribute;
}
protected Set<ItemStream> getStreams() {
return this.streams;
}
}