grails.async.DelegateAsync.groovy Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of grails-async Show documentation

Grails Web Application Framework

There is a newer version: 5.0.2

/*
 * Copyright 2013 SpringSource
 *
 * 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 grails.async

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

import org.codehaus.groovy.transform.GroovyASTTransformationClass

/**
 * An AST transformation that takes each method in the given class and adds a delegate method that returns a {@link grails.async.Promise} and executes the method asynchronously.
 * For example given the following class:
 *
 * 
 * class BookApi {
 *    List listBooksByTitle(String title) { }
 * }
 * 
 *
 * If the annotation is applied to a new class:
 *
 * 
 * @DelegateAsync(BookApi)
 * class AsyncBookApi {}
 * 
 *
 * The resulting class is transformed into:
 *
 * 
 * class AsyncBookApi {
 *     private BookApi $bookApi
 *     Promise> listBooksByTitle(String title) {
 *        (Promise>)Promises.createPromise {
 *            $bookApi.listBooksByTitle(title)
 *        }
 *     }
 * }
 * 
 *
 *
 * @author Graeme Rocher
 * @since 2.3
 */
@Documented
@Retention(RetentionPolicy.SOURCE)
@Target([ElementType.TYPE, ElementType.FIELD])
@GroovyASTTransformationClass("org.grails.async.transform.internal.DelegateAsyncTransformation")
public @interface DelegateAsync {
    Class value() default DelegateAsync
}