/*
* 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.ignite.compute;
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 java.util.List;
/**
* This annotation disables caching of task results when attached to {@link ComputeTask} class
* being executed. Use it when number of jobs within task grows too big, or jobs themselves
* are too large to keep in memory throughout task execution. By default all results are cached and passed into
* {@link ComputeTask#result(ComputeJobResult,List) ComputeTask.result(ComputeJobResult, List<ComputeJobResult>)}
* method or {@link ComputeTask#reduce(List) ComputeTask.reduce(List<ComputeJobResult>)} method.
* When this annotation is attached to a task class, then this list of job results will always be empty.
* <p>
* Note that if this annotation is attached to a task class, then job siblings list is not maintained
* and always has size of {@code 0}. This is done to make sure that in case if task emits large
* number of jobs, list of jobs siblings does not grow. This only affects the following methods
* on {@link ComputeTaskSession}:
* <ul>
* <li>{@link ComputeTaskSession#getJobSiblings()}</li>
* <li>{@link ComputeTaskSession#getJobSibling(org.apache.ignite.lang.IgniteUuid)}</li>
* <li>{@link ComputeTaskSession#refreshJobSiblings()}</li>
* </ul>
*
* Use this annotation when job results are too large to hold in memory and can be discarded
* after being processed in
* {@link ComputeTask#result(ComputeJobResult, List) ComputeTask.result(ComputeJobResult, List<ComputeJobResult>)}
* method.
*/
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE})
public @interface ComputeTaskNoResultCache {
// No-op.
}