001package org.eclipse.aether.named.redisson;
002
003/*
004 * Licensed to the Apache Software Foundation (ASF) under one
005 * or more contributor license agreements.  See the NOTICE file
006 * distributed with this work for additional information
007 * regarding copyright ownership.  The ASF licenses this file
008 * to you under the Apache License, Version 2.0 (the
009 * "License"); you may not use this file except in compliance
010 * with the License.  You may obtain a copy of the License at
011 *
012 *  http://www.apache.org/licenses/LICENSE-2.0
013 *
014 * Unless required by applicable law or agreed to in writing,
015 * software distributed under the License is distributed on an
016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017 * KIND, either express or implied.  See the License for the
018 * specific language governing permissions and limitations
019 * under the License.
020 */
021
022import org.eclipse.aether.named.support.AdaptedSemaphoreNamedLock;
023import org.redisson.api.RSemaphore;
024
025import javax.inject.Named;
026import javax.inject.Singleton;
027import java.util.concurrent.ConcurrentHashMap;
028import java.util.concurrent.ConcurrentMap;
029import java.util.concurrent.TimeUnit;
030
031/**
032 * Provider of {@link RedissonSemaphoreNamedLockFactory} using Redisson and {@link org.redisson.api.RSemaphore}.
033 */
034@Singleton
035@Named( RedissonSemaphoreNamedLockFactory.NAME )
036public class RedissonSemaphoreNamedLockFactory
037    extends RedissonNamedLockFactorySupport
038{
039    public static final String NAME = "semaphore-redisson";
040
041    private static final String TYPED_NAME_PREFIX = NAME_PREFIX + NAME + ":";
042
043    private final ConcurrentMap<String, RSemaphore> semaphores;
044
045    public RedissonSemaphoreNamedLockFactory()
046    {
047        this.semaphores = new ConcurrentHashMap<>();
048    }
049
050    @Override
051    protected AdaptedSemaphoreNamedLock createLock( final String name )
052    {
053        RSemaphore semaphore = semaphores.computeIfAbsent( name, k ->
054        {
055            RSemaphore result = redissonClient.getSemaphore( TYPED_NAME_PREFIX + k );
056            result.trySetPermits( Integer.MAX_VALUE );
057            return result;
058        } );
059        return new AdaptedSemaphoreNamedLock( name, this, new RedissonSemaphore( semaphore ) );
060    }
061
062    @Override
063    protected void destroyLock( final String name )
064    {
065        RSemaphore semaphore = semaphores.remove( name );
066        if ( semaphore == null )
067        {
068            throw new IllegalStateException( "Semaphore expected but does not exist: " + name );
069        }
070        /* Threre is no reasonable way to destroy the semaphore in Redis because we cannot know
071         * when the last process has stopped using it.
072         */
073    }
074
075    private static final class RedissonSemaphore implements AdaptedSemaphoreNamedLock.AdaptedSemaphore
076    {
077        private final RSemaphore semaphore;
078
079        private RedissonSemaphore( final RSemaphore semaphore )
080        {
081            this.semaphore = semaphore;
082        }
083
084        @Override
085        public boolean tryAcquire( final int perms, final long time, final TimeUnit unit ) throws InterruptedException
086        {
087            return semaphore.tryAcquire( perms, time, unit );
088        }
089
090        @Override
091        public void release( final int perms )
092        {
093            semaphore.release( perms );
094        }
095    }
096}