package org.eclipse.aether.named.providers;
   
   /*
    * 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;
  import java.util.concurrent.TimeUnit;
  
  import javax.inject.Named;
  import javax.inject.Singleton;
  
  import org.eclipse.aether.named.support.AdaptedSemaphoreNamedLock;
  import org.eclipse.aether.named.support.NamedLockFactorySupport;
  
  /**
   * A JVM-local named lock factory that uses named {@link Semaphore}s.
   */
  @Singleton
  @Named( LocalSemaphoreNamedLockFactory.NAME )
  public class LocalSemaphoreNamedLockFactory
      extends NamedLockFactorySupport
  {
      public static final String NAME = "semaphore-local";
  
      @Override
      protected AdaptedSemaphoreNamedLock createLock( final String name )
      {
        Semaphore semaphore = new Semaphore( Integer.MAX_VALUE );
        return new AdaptedSemaphoreNamedLock( name, this, new JVMSemaphore( semaphore ) );
      }
  
      /**
       * Adapted JVM {@link java.util.concurrent.Semaphore}.
       */
      private static final class JVMSemaphore
          implements AdaptedSemaphoreNamedLock.AdaptedSemaphore
      {
          private final Semaphore semaphore;
  
          private JVMSemaphore( final Semaphore semaphore )
          {
            this.semaphore = semaphore;
          }
  
          @Override
          public boolean tryAcquire( final int perms, final long time, final TimeUnit unit ) throws InterruptedException
          {
               return semaphore.tryAcquire( perms, time, unit );
          }
  
          @Override
          public void release( final int perms )
          {
              semaphore.release( perms );
          }
      }
  }