/*
* Copyright (C) 2006 The Guava 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
*
* 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 com.google_voltpatches.common.util.concurrent;
import com.google_voltpatches.common.annotations.Beta;
import com.google_voltpatches.common.annotations.GwtIncompatible;
import com.google_voltpatches.errorprone.annotations.CanIgnoreReturnValue;
import java.util.concurrent.Callable;
import java.util.concurrent.TimeUnit;
/**
* Produces proxies that impose a time limit on method calls to the proxied object. For example, to
* return the value of {@code target.someMethod()}, but substitute {@code DEFAULT_VALUE} if this
* method call takes over 50 ms, you can use this code:
*
* <pre>
* TimeLimiter limiter = . . .;
* TargetType proxy = limiter.newProxy(
* target, TargetType.class, 50, TimeUnit.MILLISECONDS);
* try {
* return proxy.someMethod();
* } catch (UncheckedTimeoutException e) {
* return DEFAULT_VALUE;
* }
* </pre>
*
* <p>Please see {@code SimpleTimeLimiterTest} for more usage examples.
*
* @author Kevin Bourrillion
* @since 1.0
*/
@Beta
@GwtIncompatible
public interface TimeLimiter {
/**
* Returns an instance of {@code interfaceType} that delegates all method calls to the
* {@code target} object, enforcing the specified time limit on each call. This time-limited
* delegation is also performed for calls to {@link Object#equals}, {@link Object#hashCode}, and
* {@link Object#toString}.
*
* <p>If the target method call finishes before the limit is reached, the return value or
* exception is propagated to the caller exactly as-is. If, on the other hand, the time limit is
* reached, the proxy will attempt to abort the call to the target, and will throw an
* {@link UncheckedTimeoutException} to the caller.
*
* <p>It is important to note that the primary purpose of the proxy object is to return control to
* the caller when the timeout elapses; aborting the target method call is of secondary concern.
* The particular nature and strength of the guarantees made by the proxy is
* implementation-dependent. However, it is important that each of the methods on the target
* object behaves appropriately when its thread is interrupted.
*
* @param target the object to proxy
* @param interfaceType the interface you wish the returned proxy to implement
* @param timeoutDuration with timeoutUnit, the maximum length of time that callers are willing to
* wait on each method call to the proxy
* @param timeoutUnit with timeoutDuration, the maximum length of time that callers are willing to
* wait on each method call to the proxy
* @return a time-limiting proxy
* @throws IllegalArgumentException if {@code interfaceType} is a regular class, enum, or
* annotation type, rather than an interface
*/
<T> T newProxy(T target, Class<T> interfaceType, long timeoutDuration, TimeUnit timeoutUnit);
/**
* Invokes a specified Callable, timing out after the specified time limit. If the target method
* call finished before the limit is reached, the return value or exception is propagated to the
* caller exactly as-is. If, on the other hand, the time limit is reached, we attempt to abort the
* call to the target, and throw an {@link UncheckedTimeoutException} to the caller.
*
* @param callable the Callable to execute
* @param timeoutDuration with timeoutUnit, the maximum length of time to wait
* @param timeoutUnit with timeoutDuration, the maximum length of time to wait
* @param interruptible whether to respond to thread interruption by aborting the operation and
* throwing InterruptedException; if false, the operation is allowed to complete or time out,
* and the current thread's interrupt status is re-asserted.
* @return the result returned by the Callable
* @throws InterruptedException if {@code interruptible} is true and our thread is interrupted
* during execution
* @throws UncheckedTimeoutException if the time limit is reached
* @throws Exception
*/
@CanIgnoreReturnValue
<T> T callWithTimeout(
Callable<T> callable, long timeoutDuration, TimeUnit timeoutUnit, boolean interruptible)
throws Exception;
}