/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.flink.core.testutils;
/**
* A thread that additionally catches exceptions and offers a joining method that
* re-throws the exceptions.
*
* <p>Rather than overriding {@link Thread#run()} (or supplying a {@link Runnable}), one
* needs to extends this class and implement the {@link #go()} method. That method may
* throw exceptions.
*
* <p>Exception from the {@link #go()} method are caught and re-thrown when joining this
* thread via the {@link #sync()} method.
*/
public abstract class CheckedThread extends Thread {
/** The error thrown from the main work method */
private volatile Throwable error;
// ------------------------------------------------------------------------
/**
* Unnamed checked thread.
*/
public CheckedThread() {
super();
}
/**
* Checked thread with a name.
*
* @param name
* the name of the new thread
*
* @see Thread#Thread(String)
*/
public CheckedThread(final String name) {
super(name);
}
/**
* This method needs to be overwritten to contain the main work logic.
* It takes the role of {@link Thread#run()}, but should propagate exceptions.
*
* @throws Exception The exceptions thrown here will be re-thrown in the {@link #sync()} method.
*/
public abstract void go() throws Exception;
// ------------------------------------------------------------------------
/**
* This method is final - thread work should go into the {@link #go()} method instead.
*/
@Override
public final void run() {
try {
go();
}
catch (Throwable t) {
error = t;
}
}
/**
* Waits until the thread is completed and checks whether any error occurred during
* the execution.
*
* <p>This method blocks like {@link #join()}, but performs an additional check for
* exceptions thrown from the {@link #go()} method.
*/
public void sync() throws Exception {
super.join();
// propagate the error
if (error != null) {
if (error instanceof Error) {
throw (Error) error;
}
else if (error instanceof Exception) {
throw (Exception) error;
}
else {
throw new Exception(error.getMessage(), error);
}
}
}
}