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/*
 * Copyright 2016 Davide Maestroni
 *
 * Licensed 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 com.github.dm.jrt.object.annotation;

import com.github.dm.jrt.core.routine.InvocationMode;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * Through this annotation it is possible to indicate the invocation mode of the routine wrapping
 * the target object method.
 * 
 * The only use case in which this annotation is useful, is when an interface is used as a proxy
 * of another class methods. The annotation will indicate the type of invocation to be applied to
 * the wrapping routine.
 * 

 * Note that, unless the {@link InvocationMode#PARALLEL} is specified, to each call to a method of
 * the proxy interface will correspond a single invocation of the wrapping routine.
 * 

 * In case this annotation is absent, the asynchronous invocation mode will be employed.
 * 

 * This annotation is used to decorate methods that are to be invoked in an asynchronous way.
 * 

 * Note that the piece of code inside such methods will be automatically protected so to avoid
 * concurrency issues. Though, other parts of the code inside the same class will be not.
 * 

 * In order to prevent unexpected behaviors, it is advisable to avoid using the same class fields
 * (unless immutable) in protected and non-protected code, or to call synchronous methods through
 * routines as well.
 * 

 * Remember also that, in order for the annotation to properly work at run time, the following rules
 * must be added to the project Proguard file (if employed for shrinking or obfuscation):
 * 
 *     
 *
 *         -keepattributes RuntimeVisibleAnnotations
 *         -keepclassmembers class ** {
 *              @com.github.dm.jrt.object.annotation.Invoke *;
 *         }
 *     
 * 
 * 
 * Created by davide-maestroni on 09/27/2015.
 */
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface Invoke {

  /**
   * The routine invocation mode.
   *
   * @return the invocation mode.
   */
  InvocationMode value() default InvocationMode.ASYNC;
}