| package org.apache.maven.surefire.api.util.internal; |
| |
| /* |
| * 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.atomic.AtomicInteger; |
| |
| /** |
| * Concurrency utilities. |
| * |
| * @author <a href="mailto:tibordigana@apache.org">Tibor Digana (tibor17)</a> |
| * @since 2.19 |
| */ |
| public final class ConcurrencyUtils |
| { |
| private ConcurrencyUtils() |
| { |
| throw new IllegalStateException( "not instantiable constructor" ); |
| } |
| |
| /** |
| * Decreases {@code counter} to zero, or does not change the counter if negative. |
| * This method pretends been atomic. Only one thread can succeed setting the counter to zero. |
| * |
| * @param counter atomic counter |
| * @return {@code true} if this Thread modified concurrent counter from any positive number down to zero. |
| */ |
| @SuppressWarnings( "checkstyle:emptyforiteratorpad" ) |
| public static boolean countDownToZero( AtomicInteger counter ) |
| { |
| for (;;) |
| { |
| int c = counter.get(); |
| if ( c > 0 ) |
| { |
| int newCounter = c - 1; |
| if ( counter.compareAndSet( c, newCounter ) ) |
| { |
| return newCounter == 0; |
| } |
| } |
| else |
| { |
| return false; |
| } |
| } |
| } |
| } |