org.sosy_lab.java_smt.basicimpl.ShutdownHook Maven / Gradle / Ivy
Show all versions of java-smt Show documentation
// This file is part of JavaSMT,
// an API wrapper for a collection of SMT solvers:
// https://github.com/sosy-lab/java-smt
//
// SPDX-FileCopyrightText: 2021 Dirk Beyer
//
// SPDX-License-Identifier: Apache-2.0
package org.sosy_lab.java_smt.basicimpl;
import com.google.common.base.Preconditions;
import java.util.concurrent.atomic.AtomicBoolean;
import org.checkerframework.checker.nullness.qual.Nullable;
import org.sosy_lab.common.ShutdownNotifier;
import org.sosy_lab.common.ShutdownNotifier.ShutdownRequestListener;
/**
* A utility class for interrupting a parallel running solver thread.
*
* The hook is active directly after its construction until calling the method {@link
* ShutdownHook#close()} and forwards all shutdown requests to the provided method.
*/
public final class ShutdownHook implements ShutdownRequestListener, AutoCloseable {
private final ShutdownNotifier shutdownNotifier;
private final Runnable interruptCall;
public ShutdownHook(ShutdownNotifier pShutdownNotifier, Runnable pInterruptCall) {
interruptCall = Preconditions.checkNotNull(pInterruptCall);
shutdownNotifier = Preconditions.checkNotNull(pShutdownNotifier);
shutdownNotifier.register(this);
}
final AtomicBoolean isActiveHook = new AtomicBoolean(true);
// Due to a small delay in some solvers, interrupts have no effect when it is called too soon,
// so we repeat cancellation until the solver's method returns and terminates.
// In that case, we should call #close and terminate this hook.
@Override
public void shutdownRequested(@Nullable String reasonUnused) {
while (isActiveHook.get()) { // flag is reset in #cancelHook
interruptCall.run();
try {
Thread.sleep(10); // let's wait a few steps
} catch (InterruptedException e) {
// ignore
}
}
}
@Override
public void close() {
isActiveHook.set(false);
shutdownNotifier.unregister(this);
}
}