com.datatorrent.api.annotation.Stateless Maven / Gradle / Ivy
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/**
* 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 com.datatorrent.api.annotation;
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;
/**
* When a class or interface is annotated with this annotation, the object which are
* instanceof such a class or interface are assumed to have the same serialized state
* it attains after it's configured completely.
*
* This annotation is typically is used to mark the operator Stateless. That means
* the checkpointing for such an operator will be skipped. In case of failure the
* serialized instance of the operator which was submitted to the DAG will be used to
* reinstantiate it and used to recover the application from the assumed checkpoint
* onwards.
*
* @since 0.9.4
*/
@Documented
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface Stateless
{
/**
* WindowId of the unaltered state of an operator.
* The first windowId during which data may be given to the operator is zero.
*/
long WINDOW_ID = -1;
}