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ThreadPrioritySnapshot.java
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ThreadPrioritySnapshot.java
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/*
* Copyright (c) 2018,2019 Contributors to the Eclipse Foundation
*
* See the NOTICE file(s) distributed with this work for additional
* information regarding copyright ownership.
*
* 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.eclipse.microprofile.context.tck.contexts.priority.spi;
import java.util.concurrent.atomic.AtomicBoolean;
import org.eclipse.microprofile.context.spi.ThreadContextController;
import org.eclipse.microprofile.context.spi.ThreadContextSnapshot;
/**
* Represents a saved copy of 'thread priority' context.
*/
public class ThreadPrioritySnapshot implements ThreadContextSnapshot {
private final int priority;
ThreadPrioritySnapshot(int priority) {
this.priority = priority;
}
/**
* Apply the saved thread priority to the current thread, but
* first storing a copying of the thread priority that was previously on the thread
* so that the previous thread priority can later be restored via the returned
* ThreadContextController.
*/
@Override
public ThreadContextController begin() {
Thread thread = Thread.currentThread();
int priorityToRestore = thread.getPriority();
AtomicBoolean restored = new AtomicBoolean();
ThreadContextController contextRestorer = () -> {
if (restored.compareAndSet(false, true)) {
thread.setPriority(priorityToRestore);
}
else {
throw new IllegalStateException();
}
};
thread.setPriority(priority);
return contextRestorer;
}
// For easier debug
@Override
public String toString() {
return "ThreadPrioritySnapshot@" + Integer.toHexString(System.identityHashCode(this)) + ": " + priority;
}
}