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Core domain for batch processing, expressing a domain of Jobs, Steps, Chunks, etc
/*
* Copyright 2006-2023 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.scope.context;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Properties;
import java.util.Set;
import org.springframework.batch.core.JobExecution;
import org.springframework.batch.core.JobInstance;
import org.springframework.batch.core.JobParameter;
import org.springframework.batch.core.JobParameters;
import org.springframework.batch.core.UnexpectedJobExecutionException;
import org.springframework.batch.core.scope.StepScope;
import org.springframework.batch.item.ExecutionContext;
import org.springframework.batch.repeat.context.SynchronizedAttributeAccessor;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
/**
* A context object that can be used to interrogate the current {@link JobExecution} and
* some of its associated properties using expressions based on bean paths. Has public
* getters for the job execution and convenience methods for accessing commonly used
* properties like the {@link ExecutionContext} associated with the job execution.
*
* @author Dave Syer
* @author Jimmy Praet (create JobContext based on {@link StepContext})
* @author Mahmoud Ben Hassine
* @since 3.0
*/
public class JobContext extends SynchronizedAttributeAccessor {
private final JobExecution jobExecution;
private final Map> callbacks = new HashMap<>();
public JobContext(JobExecution jobExecution) {
super();
Assert.notNull(jobExecution, "A JobContext must have a non-null JobExecution");
this.jobExecution = jobExecution;
}
/**
* Convenient accessor for current job name identifier.
* @return the job name identifier of the enclosing {@link JobInstance} associated
* with the current {@link JobExecution}
*/
public String getJobName() {
Assert.state(jobExecution.getJobInstance() != null, "JobExecution does not have a JobInstance");
return jobExecution.getJobInstance().getJobName();
}
/**
* Convenient accessor for System properties to make it easy to access them from
* placeholder expressions.
* @return the current System properties
*/
public Properties getSystemProperties() {
return System.getProperties();
}
/**
* @return a map containing the items from the job {@link ExecutionContext}
*/
public Map getJobExecutionContext() {
Map result = new HashMap<>();
for (Entry entry : jobExecution.getExecutionContext().entrySet()) {
result.put(entry.getKey(), entry.getValue());
}
return Collections.unmodifiableMap(result);
}
/**
* @return a map containing the items from the {@link JobParameters}
*/
public Map getJobParameters() {
Map result = new HashMap<>();
for (Entry> entry : jobExecution.getJobParameters().getParameters().entrySet()) {
result.put(entry.getKey(), entry.getValue().getValue());
}
return Collections.unmodifiableMap(result);
}
/**
* Allow clients to register callbacks for clean up on close.
* @param name the callback id (unique attribute key in this context)
* @param callback a callback to execute on close
*/
public void registerDestructionCallback(String name, Runnable callback) {
synchronized (callbacks) {
Set set = callbacks.computeIfAbsent(name, k -> new HashSet<>());
set.add(callback);
}
}
private void unregisterDestructionCallbacks(String name) {
synchronized (callbacks) {
callbacks.remove(name);
}
}
/**
* Override base class behaviour to ensure destruction callbacks are unregistered as
* well as the default behaviour.
*
* @see SynchronizedAttributeAccessor#removeAttribute(String)
*/
@Override
@Nullable
public Object removeAttribute(String name) {
unregisterDestructionCallbacks(name);
return super.removeAttribute(name);
}
/**
* Clean up the context at the end of a step execution. Must be called once at the end
* of a step execution to honour the destruction callback contract from the
* {@link StepScope}.
*/
public void close() {
List errors = new ArrayList<>();
Map> copy = Collections.unmodifiableMap(callbacks);
for (Entry> entry : copy.entrySet()) {
Set set = entry.getValue();
for (Runnable callback : set) {
if (callback != null) {
/*
* The documentation of the interface says that these callbacks must
* not throw exceptions, but we don't trust them necessarily...
*/
try {
callback.run();
}
catch (RuntimeException t) {
errors.add(t);
}
}
}
}
if (errors.isEmpty()) {
return;
}
Exception error = errors.get(0);
if (error instanceof RuntimeException) {
throw (RuntimeException) error;
}
else {
throw new UnexpectedJobExecutionException(
"Could not close step context, rethrowing first of " + errors.size() + " exceptions.", error);
}
}
/**
* The current {@link JobExecution} that is active in this context.
* @return the current {@link JobExecution}
*/
public JobExecution getJobExecution() {
return jobExecution;
}
/**
* @return unique identifier for this context based on the step execution
*/
public String getId() {
Assert.state(jobExecution.getId() != null,
"JobExecution has no id. " + "It must be saved before it can be used in job scope.");
return "jobExecution#" + jobExecution.getId();
}
/**
* Extend the base class method to include the job execution itself as a key (i.e. two
* contexts are only equal if their job executions are the same).
*/
@Override
public boolean equals(Object other) {
if (!(other instanceof JobContext context)) {
return false;
}
if (other == this) {
return true;
}
if (context.jobExecution == jobExecution) {
return true;
}
return jobExecution.equals(context.jobExecution);
}
/**
* Overrides the default behaviour to provide a hash code based only on the job
* execution.
*/
@Override
public int hashCode() {
return jobExecution.hashCode();
}
@Override
public String toString() {
return super.toString() + ", jobExecutionContext=" + getJobExecutionContext() + ", jobParameters="
+ getJobParameters();
}
}