001// Copyright 2010 The Apache Software Foundation
002//
003// Licensed under the Apache License, Version 2.0 (the "License");
004// you may not use this file except in compliance with the License.
005// You may obtain a copy of the License at
006//
007// http://www.apache.org/licenses/LICENSE-2.0
008//
009// Unless required by applicable law or agreed to in writing, software
010// distributed under the License is distributed on an "AS IS" BASIS,
011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012// See the License for the specific language governing permissions and
013// limitations under the License.
014
015package org.apache.tapestry5.annotations;
016
017import static java.lang.annotation.RetentionPolicy.RUNTIME;
018import static org.apache.tapestry5.ioc.annotations.AnnotationUseContext.COMPONENT;
019import static org.apache.tapestry5.ioc.annotations.AnnotationUseContext.MIXIN;
020import static org.apache.tapestry5.ioc.annotations.AnnotationUseContext.PAGE;
021
022import java.lang.annotation.Documented;
023import java.lang.annotation.ElementType;
024import java.lang.annotation.Retention;
025import java.lang.annotation.Target;
026
027import org.apache.tapestry5.internal.transform.HeartbeatDeferredWorker;
028import org.apache.tapestry5.ioc.annotations.UseWith;
029import org.apache.tapestry5.services.Heartbeat;
030
031/**
032 * Marks a component method as deferred until the end of the {@link Heartbeat}. This
033 * is only allowed on void methods that do not throw exceptions. The invocation is captured
034 * and will execute at the end of the current Heartbeat.
035 * <p>
036 * This annotation should be used with care, since deferring the invocation can change its semantics. For example, the
037 * value stored in instance variables may change between the time the method is invoked and the time it eventually
038 * executes. Likewise, runtime exceptions thrown by the method can not be caught by the invoking method.
039 * <p>
040 * Annotated methods must return void, and not declare any checked exceptions.
041 * 
042 * @since 5.2.0
043 * @see HeartbeatDeferredWorker
044 */
045@Target(ElementType.METHOD)
046@Retention(RUNTIME)
047@Documented
048@UseWith(
049{ COMPONENT, MIXIN, PAGE })
050public @interface HeartbeatDeferred
051{
052
053}