org.eclipse.aether.named.NamedLock Maven / Gradle / Ivy
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* 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.eclipse.aether.named;
import java.util.concurrent.TimeUnit;
/**
* A named lock, functionally similar to existing JVM and other implementations. Must support boxing (reentrancy), but
* no lock upgrade is supported. The lock instance obtained from lock factory must be treated as a resource, best in
* try-with-resource block. Usual pattern to use this lock:
*
* try (NamedLock lock = factory.getLock("resourceName")) {
* if (lock.lockExclusively(10L, Timeunit.SECONDS)) {
* try {
* ... exclusive access to "resourceName" resource gained here
* }
* finally {
* lock.unlock();
* }
* }
* else {
* ... failed to gain access within specified time, handle it
* }
* }
*
*/
public interface NamedLock extends AutoCloseable {
/**
* Returns this instance name, never null
*/
String name();
/**
* Tries to lock shared, may block for given time. If successful, returns {@code true}.
*/
boolean lockShared(long time, TimeUnit unit) throws InterruptedException;
/**
* Tries to lock exclusively, may block for given time. If successful, returns {@code true}.
*/
boolean lockExclusively(long time, TimeUnit unit) throws InterruptedException;
/**
* Unlocks the lock, must be invoked by caller after one of the {@link #lockShared(long, TimeUnit)} or {@link
* #lockExclusively(long, TimeUnit)}.
*/
void unlock();
/**
* Closes the lock resource. Lock MUST be unlocked using {@link #unlock()} in case any locking happened on it. After
* invoking this method, the lock instance MUST NOT be used anymore. If lock for same name needed, a new instance
* should be obtained from factory using {@link NamedLockFactory#getLock(String)}. Ideally, instances are to be used
* within try-with-resource blocks, so calling this method directly is not really needed, nor advised.
*/
@Override
void close();
}