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/*
* Copyright 2006-2021 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
*
* https://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.lang.reflect.Method;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.Set;
import java.util.function.Function;
import org.springframework.batch.core.ChunkListener;
import org.springframework.batch.core.ItemProcessListener;
import org.springframework.batch.core.ItemReadListener;
import org.springframework.batch.core.ItemWriteListener;
import org.springframework.batch.core.StepExecutionListener;
import org.springframework.batch.core.StepListener;
import org.springframework.batch.core.annotation.AfterProcess;
import org.springframework.batch.core.annotation.AfterRead;
import org.springframework.batch.core.annotation.AfterWrite;
import org.springframework.batch.core.annotation.BeforeProcess;
import org.springframework.batch.core.annotation.BeforeRead;
import org.springframework.batch.core.annotation.BeforeWrite;
import org.springframework.batch.core.annotation.OnProcessError;
import org.springframework.batch.core.annotation.OnReadError;
import org.springframework.batch.core.annotation.OnWriteError;
import org.springframework.batch.core.listener.StepListenerFactoryBean;
import org.springframework.batch.core.step.item.ChunkOrientedTasklet;
import org.springframework.batch.core.step.item.SimpleChunkProcessor;
import org.springframework.batch.core.step.item.SimpleChunkProvider;
import org.springframework.batch.core.step.tasklet.Tasklet;
import org.springframework.batch.core.step.tasklet.TaskletStep;
import org.springframework.batch.item.ItemProcessor;
import org.springframework.batch.item.ItemReader;
import org.springframework.batch.item.ItemStream;
import org.springframework.batch.item.ItemWriter;
import org.springframework.batch.item.function.FunctionItemProcessor;
import org.springframework.batch.repeat.CompletionPolicy;
import org.springframework.batch.repeat.RepeatOperations;
import org.springframework.batch.repeat.policy.SimpleCompletionPolicy;
import org.springframework.batch.repeat.support.RepeatTemplate;
import org.springframework.batch.support.ReflectionUtils;
import org.springframework.util.Assert;
/**
* Step builder for simple item processing (chunk oriented) steps. Items are read and cached in chunks, and then
* processed (transformed) and written (optionally either the processor or the writer can be omitted) all in the same
* transaction.
*
* @see FaultTolerantStepBuilder for a step that handles retry and skip of failed items
*
* @author Dave Syer
* @author Mahmoud Ben Hassine
*
* @since 2.2
*/
public class SimpleStepBuilder extends AbstractTaskletStepBuilder> {
private static final int DEFAULT_COMMIT_INTERVAL = 1;
private ItemReader reader;
private ItemWriter writer;
private ItemProcessor processor;
private Function itemProcessorFunction;
private int chunkSize = 0;
private RepeatOperations chunkOperations;
private CompletionPolicy completionPolicy;
private Set itemListeners = new LinkedHashSet<>();
private boolean readerTransactionalQueue = false;
/**
* Create a new builder initialized with any properties in the parent. The parent is copied, so it can be re-used.
*
* @param parent a parent helper containing common step properties
*/
public SimpleStepBuilder(StepBuilderHelper parent) {
super(parent);
}
/**
* Create a new builder initialized with any properties in the parent. The parent is copied, so it can be re-used.
*
* @param parent a parent helper containing common step properties
*/
protected SimpleStepBuilder(SimpleStepBuilder parent) {
super(parent);
this.chunkSize = parent.chunkSize;
this.completionPolicy = parent.completionPolicy;
this.chunkOperations = parent.chunkOperations;
this.reader = parent.reader;
this.writer = parent.writer;
this.processor = parent.processor;
this.itemListeners = parent.itemListeners;
this.readerTransactionalQueue = parent.readerTransactionalQueue;
}
public FaultTolerantStepBuilder faultTolerant() {
return new FaultTolerantStepBuilder<>(this);
}
/**
* Build a step with the reader, writer, processor as provided.
*
* @see org.springframework.batch.core.step.builder.AbstractTaskletStepBuilder#build()
*/
@Override
public TaskletStep build() {
registerStepListenerAsItemListener();
registerAsStreamsAndListeners(reader, processor, writer);
return super.build();
}
protected void registerStepListenerAsItemListener() {
for (StepExecutionListener stepExecutionListener: properties.getStepExecutionListeners()){
checkAndAddItemListener(stepExecutionListener);
}
for (ChunkListener chunkListener: this.chunkListeners){
checkAndAddItemListener(chunkListener);
}
}
@SuppressWarnings("unchecked")
private void checkAndAddItemListener(StepListener stepListener) {
if (stepListener instanceof ItemReadListener){
listener((ItemReadListener)stepListener);
}
if (stepListener instanceof ItemProcessListener){
listener((ItemProcessListener)stepListener);
}
if (stepListener instanceof ItemWriteListener){
listener((ItemWriteListener)stepListener);
}
}
@Override
protected Tasklet createTasklet() {
Assert.state(reader != null, "ItemReader must be provided");
Assert.state(writer != null, "ItemWriter must be provided");
RepeatOperations repeatOperations = createChunkOperations();
SimpleChunkProvider chunkProvider = new SimpleChunkProvider<>(getReader(), repeatOperations);
SimpleChunkProcessor chunkProcessor = new SimpleChunkProcessor<>(getProcessor(), getWriter());
chunkProvider.setListeners(new ArrayList<>(itemListeners));
chunkProcessor.setListeners(new ArrayList<>(itemListeners));
ChunkOrientedTasklet tasklet = new ChunkOrientedTasklet<>(chunkProvider, chunkProcessor);
tasklet.setBuffering(!readerTransactionalQueue);
return tasklet;
}
/**
* Sets the chunk size or commit interval for this step. This is the maximum number of items that will be read
* before processing starts in a single transaction. Not compatible with {@link #completionPolicy}
* .
*
* @param chunkSize the chunk size (a.k.a commit interval)
* @return this for fluent chaining
*/
public SimpleStepBuilder chunk(int chunkSize) {
Assert.state(completionPolicy == null || chunkSize == 0,
"You must specify either a chunkCompletionPolicy or a commitInterval but not both.");
this.chunkSize = chunkSize;
return this;
}
/**
* Sets a completion policy for the chunk processing. Items are read until this policy determines that a chunk is
* complete, giving more control than with just the {@link #chunk(int) chunk size} (or commit interval).
*
* @param completionPolicy a completion policy for the chunk
* @return this for fluent chaining
*/
public SimpleStepBuilder chunk(CompletionPolicy completionPolicy) {
Assert.state(chunkSize == 0 || completionPolicy == null,
"You must specify either a chunkCompletionPolicy or a commitInterval but not both.");
this.completionPolicy = completionPolicy;
return this;
}
/**
* An item reader that provides a stream of items. Will be automatically registered as a {@link #stream(ItemStream)}
* or listener if it implements the corresponding interface. By default assumed to be non-transactional.
*
* @see #readerTransactionalQueue
* @param reader an item reader
* @return this for fluent chaining
*/
public SimpleStepBuilder reader(ItemReader reader) {
this.reader = reader;
return this;
}
/**
* An item writer that writes a chunk of items. Will be automatically registered as a {@link #stream(ItemStream)} or
* listener if it implements the corresponding interface.
*
* @param writer an item writer
* @return this for fluent chaining
*/
public SimpleStepBuilder writer(ItemWriter writer) {
this.writer = writer;
return this;
}
/**
* An item processor that processes or transforms a stream of items. Will be automatically registered as a
* {@link #stream(ItemStream)} or listener if it implements the corresponding interface.
*
* @param processor an item processor
* @return this for fluent chaining
*/
public SimpleStepBuilder processor(ItemProcessor processor) {
this.processor = processor;
return this;
}
/**
* A {@link Function} to be delegated to as an {@link ItemProcessor}. If this is set,
* it will take precedence over any {@code ItemProcessor} configured via
* {@link #processor(ItemProcessor)}.
*
* @param function the function to delegate item processing to
* @return this for fluent chaining
*/
public SimpleStepBuilder processor(Function function) {
this.itemProcessorFunction = function;
return this;
}
/**
* Sets a flag to say that the reader is transactional (usually a queue), which is to say that failed items might be
* rolled back and re-presented in a subsequent transaction. Default is false, meaning that the items are read
* outside a transaction and possibly cached.
*
* @return this for fluent chaining
*/
public SimpleStepBuilder readerIsTransactionalQueue() {
this.readerTransactionalQueue = true;
return this;
}
/**
* Registers objects using the annotation based listener configuration.
*
* @param listener the object that has a method configured with listener annotation
* @return this for fluent chaining
*/
@SuppressWarnings("unchecked")
@Override
public SimpleStepBuilder listener(Object listener) {
super.listener(listener);
Set itemListenerMethods = new HashSet<>();
itemListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), BeforeRead.class));
itemListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), AfterRead.class));
itemListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), BeforeProcess.class));
itemListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), AfterProcess.class));
itemListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), BeforeWrite.class));
itemListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), AfterWrite.class));
itemListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), OnReadError.class));
itemListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), OnProcessError.class));
itemListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), OnWriteError.class));
if(itemListenerMethods.size() > 0) {
StepListenerFactoryBean factory = new StepListenerFactoryBean();
factory.setDelegate(listener);
itemListeners.add((StepListener) factory.getObject());
}
@SuppressWarnings("unchecked")
SimpleStepBuilder result = this;
return result;
}
/**
* Register an item reader listener.
*
* @param listener the listener to register
* @return this for fluent chaining
*/
public SimpleStepBuilder listener(ItemReadListener listener) {
itemListeners.add(listener);
return this;
}
/**
* Register an item writer listener.
*
* @param listener the listener to register
* @return this for fluent chaining
*/
public SimpleStepBuilder listener(ItemWriteListener listener) {
itemListeners.add(listener);
return this;
}
/**
* Register an item processor listener.
*
* @param listener the listener to register
* @return this for fluent chaining
*/
public SimpleStepBuilder listener(ItemProcessListener listener) {
itemListeners.add(listener);
return this;
}
/**
* Instead of a {@link #chunk(int) chunk size} or {@link #chunk(CompletionPolicy) completion policy} you can provide
* a complete repeat operations instance that handles the iteration over the item reader.
*
* @param repeatTemplate a complete repeat template for the chunk
* @return this for fluent chaining
*/
public SimpleStepBuilder chunkOperations(RepeatOperations repeatTemplate) {
this.chunkOperations = repeatTemplate;
return this;
}
protected RepeatOperations createChunkOperations() {
RepeatOperations repeatOperations = chunkOperations;
if (repeatOperations == null) {
RepeatTemplate repeatTemplate = new RepeatTemplate();
repeatTemplate.setCompletionPolicy(getChunkCompletionPolicy());
repeatOperations = repeatTemplate;
}
return repeatOperations;
}
protected ItemReader getReader() {
return reader;
}
protected ItemWriter getWriter() {
return writer;
}
protected ItemProcessor getProcessor() {
if(this.itemProcessorFunction != null) {
this.processor = new FunctionItemProcessor<>(this.itemProcessorFunction);
}
return processor;
}
protected int getChunkSize() {
return chunkSize;
}
protected boolean isReaderTransactionalQueue() {
return readerTransactionalQueue;
}
protected Set getItemListeners() {
return itemListeners;
}
/**
* @return a {@link CompletionPolicy} consistent with the chunk size and injected policy (if present).
*/
protected CompletionPolicy getChunkCompletionPolicy() {
Assert.state(!(completionPolicy != null && chunkSize > 0),
"You must specify either a chunkCompletionPolicy or a commitInterval but not both.");
Assert.state(chunkSize >= 0, "The commitInterval must be positive or zero (for default value).");
if (completionPolicy != null) {
return completionPolicy;
}
if (chunkSize == 0) {
if (logger.isInfoEnabled()) {
logger.info("Setting commit interval to default value (" + DEFAULT_COMMIT_INTERVAL + ")");
}
chunkSize = DEFAULT_COMMIT_INTERVAL;
}
return new SimpleCompletionPolicy(chunkSize);
}
protected void registerAsStreamsAndListeners(ItemReader itemReader,
ItemProcessor itemProcessor, ItemWriter itemWriter) {
for (Object itemHandler : new Object[] { itemReader, itemWriter, itemProcessor }) {
if (itemHandler instanceof ItemStream) {
stream((ItemStream) itemHandler);
}
if (StepListenerFactoryBean.isListener(itemHandler)) {
StepListener listener = StepListenerFactoryBean.getListener(itemHandler);
if (listener instanceof StepExecutionListener) {
listener((StepExecutionListener) listener);
}
if (listener instanceof ChunkListener) {
listener((ChunkListener) listener);
}
if (listener instanceof ItemReadListener || listener instanceof ItemProcessListener
|| listener instanceof ItemWriteListener) {
itemListeners.add(listener);
}
}
}
}
}
