Locked.java

/*
 * 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.deltaspike.core.api.lock;

import javax.enterprise.inject.spi.AnnotatedMethod;
import javax.enterprise.util.Nonbinding;
import javax.interceptor.InterceptorBinding;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.ReadWriteLock;

import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.ElementType.TYPE;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * The access to the method is protected by a read/write lock.
 */
@InterceptorBinding
@Retention(RUNTIME)
@Target({ TYPE, METHOD })
public @interface Locked
{
    /**
     * @return if the lock is fair.
     */
    @Nonbinding
    boolean fair() default false;

    /**
     * @return the operation used on the lock, default to read but you can use write.
     */
    @Nonbinding
    Operation operation() default Operation.READ;

    /**
     * @return how to retrieve the lock for this method. Default uses a lock per class.
     */
    @Nonbinding
    Class<? extends LockFactory> factory() default LockFactory.class;

    /**
     * @return the access timeout for this method. Ignored by default since it is 0.
     */
    @Nonbinding
    long timeout() default 0L;

    /**
     * @return the timeout unit (default ms).
     */
    @Nonbinding
    TimeUnit timeoutUnit() default TimeUnit.MILLISECONDS;

    enum Operation
    {
        READ, WRITE
    }

    /**
     * Provide a way to switch the ReadWriteLock implementation for @Locked.
     */
    interface LockFactory
    {
        /**
         * @param method the intercepted method.
         * @param fair is the lock fair.
         * @return a read/write lock used for @Locked implementation.
         */
        ReadWriteLock newLock(AnnotatedMethod<?> method, boolean fair);
    }
}