| package org.apache.maven.surefire.junitcore.pc; |
| |
| /* |
| * 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. |
| */ |
| |
| import java.util.concurrent.Semaphore; |
| |
| /** |
| * @author Tibor Digana (tibor17) |
| * @see Balancer |
| * @since 2.16 |
| */ |
| final class ThreadResourcesBalancer |
| implements Balancer |
| { |
| private final Semaphore balancer; |
| |
| private final int numPermits; |
| |
| /** |
| * <tt>fair</tt> set to false. |
| * |
| * @param numPermits number of permits to acquire when maintaining concurrency on tests. |
| * Must be >0 and < {@link Integer#MAX_VALUE}. |
| * @see #ThreadResourcesBalancer(int, boolean) |
| */ |
| ThreadResourcesBalancer( int numPermits ) |
| { |
| this( numPermits, false ); |
| } |
| |
| /** |
| * @param numPermits number of permits to acquire when maintaining concurrency on tests. |
| * Must be >0 and < {@link Integer#MAX_VALUE}. |
| * @param fair {@code true} guarantees the waiting schedulers to wake up in order they acquired a permit |
| * @throws IllegalArgumentException if <tt>numPermits</tt> is not positive number |
| */ |
| ThreadResourcesBalancer( int numPermits, boolean fair ) |
| { |
| if ( numPermits <= 0 ) |
| { |
| throw new IllegalArgumentException( |
| String.format( "numPermits=%d should be positive number", numPermits ) ); |
| } |
| balancer = new Semaphore( numPermits, fair ); |
| this.numPermits = numPermits; |
| } |
| |
| /** |
| * Acquires a permit from this balancer, blocking until one is available. |
| * |
| * @return {@code true} if current thread is <b>NOT</b> interrupted |
| * while waiting for a permit. |
| */ |
| @Override |
| public boolean acquirePermit() |
| { |
| try |
| { |
| balancer.acquire(); |
| return true; |
| } |
| catch ( InterruptedException e ) |
| { |
| return false; |
| } |
| } |
| |
| /** |
| * Releases a permit, returning it to the balancer. |
| */ |
| @Override |
| public void releasePermit() |
| { |
| balancer.release(); |
| } |
| |
| @Override |
| public void releaseAllPermits() |
| { |
| balancer.release( numPermits ); |
| } |
| } |