/*
* Copyright 2012-2015 Ray Holder
*
* 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 me.hao0.antares.common.retry;
import com.google.common.base.Preconditions;
import com.google.common.util.concurrent.SimpleTimeLimiter;
import com.google.common.util.concurrent.TimeLimiter;
import javax.annotation.Nonnull;
import javax.annotation.concurrent.Immutable;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.TimeUnit;
/**
* Factory class for instances of {@link AttemptTimeLimiter}
*
* @author Jason Dunkelberger (dirkraft)
*/
public class AttemptTimeLimiters {
private AttemptTimeLimiters() {
}
/**
* @param <V> The type of the computation result.
* @return an {@link AttemptTimeLimiter} impl which has no time limit
*/
public static <V> AttemptTimeLimiter<V> noTimeLimit() {
return new NoAttemptTimeLimit<V>();
}
/**
* For control over thread management, it is preferable to offer an {@link ExecutorService} through the other
* factory method, {@link #fixedTimeLimit(long, TimeUnit, ExecutorService)}. See the note on
* {@link SimpleTimeLimiter#SimpleTimeLimiter(ExecutorService)}, which this AttemptTimeLimiter uses.
*
* @param duration that an attempt may persist before being circumvented
* @param timeUnit of the 'duration' arg
* @param <V> the type of the computation result
* @return an {@link AttemptTimeLimiter} with a fixed time limit for each attempt
*/
public static <V> AttemptTimeLimiter<V> fixedTimeLimit(long duration, @Nonnull TimeUnit timeUnit) {
Preconditions.checkNotNull(timeUnit);
return new FixedAttemptTimeLimit<V>(duration, timeUnit);
}
/**
* @param duration that an attempt may persist before being circumvented
* @param timeUnit of the 'duration' arg
* @param executorService used to enforce time limit
* @param <V> the type of the computation result
* @return an {@link AttemptTimeLimiter} with a fixed time limit for each attempt
*/
public static <V> AttemptTimeLimiter<V> fixedTimeLimit(long duration, @Nonnull TimeUnit timeUnit, @Nonnull ExecutorService executorService) {
Preconditions.checkNotNull(timeUnit);
return new FixedAttemptTimeLimit<V>(duration, timeUnit, executorService);
}
@Immutable
private static final class NoAttemptTimeLimit<V> implements AttemptTimeLimiter<V> {
@Override
public V call(Callable<V> callable) throws Exception {
return callable.call();
}
}
@Immutable
private static final class FixedAttemptTimeLimit<V> implements AttemptTimeLimiter<V> {
private final TimeLimiter timeLimiter;
private final long duration;
private final TimeUnit timeUnit;
public FixedAttemptTimeLimit(long duration, @Nonnull TimeUnit timeUnit) {
this(new SimpleTimeLimiter(), duration, timeUnit);
}
public FixedAttemptTimeLimit(long duration, @Nonnull TimeUnit timeUnit, @Nonnull ExecutorService executorService) {
this(new SimpleTimeLimiter(executorService), duration, timeUnit);
}
private FixedAttemptTimeLimit(@Nonnull TimeLimiter timeLimiter, long duration, @Nonnull TimeUnit timeUnit) {
Preconditions.checkNotNull(timeLimiter);
Preconditions.checkNotNull(timeUnit);
this.timeLimiter = timeLimiter;
this.duration = duration;
this.timeUnit = timeUnit;
}
@Override
public V call(Callable<V> callable) throws Exception {
return timeLimiter.callWithTimeout(callable, duration, timeUnit, true);
}
}
}