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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

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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.apache.activemq.artemis.utils;

import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.AbstractQueuedSynchronizer;

public abstract class AbstractLatch {

   /**
    * Look at the doc and examples provided by AbstractQueuedSynchronizer for more information
    *
    * @see AbstractQueuedSynchronizer
    */
   @SuppressWarnings("serial")
   protected static class CountSync extends AbstractQueuedSynchronizer {

      private CountSync(int count) {
         setState(count);
      }

      public int getCount() {
         return getState();
      }

      public void setCount(final int count) {
         setState(count);
      }

      @Override
      public int tryAcquireShared(final int numberOfAqcquires) {
         return getState() == 0 ? 1 : -1;
      }

      public void add() {
         for (;;) {
            int actualState = getState();
            int newState = actualState + 1;
            if (compareAndSetState(actualState, newState)) {
               return;
            }
         }
      }

      @Override
      public boolean tryReleaseShared(final int numberOfReleases) {
         for (;;) {
            int actualState = getState();
            if (actualState == 0) {
               return true;
            }

            int newState = actualState - numberOfReleases;

            if (newState < 0) {
               newState = 0;
            }

            if (compareAndSetState(actualState, newState)) {
               return newState == 0;
            }
         }
      }
   }

   protected final CountSync control;

   public AbstractLatch() {
      this(0);
   }

   public AbstractLatch(final int count) {
      control = new CountSync(count);
   }

   public int getCount() {
      return control.getCount();
   }

   public void setCount(final int count) {
      control.setCount(count);
   }

   public void countUp() {
      control.add();
   }

   public abstract void countDown();

   public abstract void countDown(int count);

   public void await() throws InterruptedException {
      control.acquireSharedInterruptibly(1);
   }

   public boolean await(final long milliseconds) throws InterruptedException {
      return control.tryAcquireSharedNanos(1, TimeUnit.MILLISECONDS.toNanos(milliseconds));
   }

   public boolean await(final long timeWait, TimeUnit timeUnit) throws InterruptedException {
      return control.tryAcquireSharedNanos(1, timeUnit.toNanos(timeWait));
   }
}