com.amazonaws.services.simpleworkflow.flow.worker.DecisionTaskHandler Maven / Gradle / Ivy

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The Amazon Web Services SDK for Java provides Java APIs for building software on AWS' cost-effective, scalable, and reliable infrastructure products. The AWS Java SDK allows developers to code against APIs for all of Amazon's infrastructure web services (Amazon S3, Amazon EC2, Amazon SQS, Amazon Relational Database Service, Amazon AutoScaling, etc).

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/*
 * Copyright 2012-2014 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License").
 * You may not use this file except in compliance with the License.
 * A copy of the License is located at
 *
 *  http://aws.amazon.com/apache2.0
 *
 * or in the "license" file accompanying this file. This file 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.amazonaws.services.simpleworkflow.flow.worker;

import java.util.Iterator;
import java.util.List;
import java.util.Map;

import com.amazonaws.services.simpleworkflow.AmazonSimpleWorkflow;
import com.amazonaws.services.simpleworkflow.flow.core.AsyncTaskInfo;
import com.amazonaws.services.simpleworkflow.model.DecisionTask;
import com.amazonaws.services.simpleworkflow.model.RespondDecisionTaskCompletedRequest;

/**
 * Base class for workflow task handlers. Extend this class to implement custom
 * deciders that can be executed using a
 * {@link WorkflowTaskPollingExecutorService}.
 * 
 * @author fateev, suskin
 * 
 * @see WorkflowTaskPollingExecutorService
 */
public abstract class DecisionTaskHandler {

    /**
     * The implementation should be called when a polling SWF Decider receives a
     * new WorkflowTask. Later, that decider should call one of
     * {@link #respondWorkflowTaskCompleted(String, Transition, AmazonSimpleWorkflow)}
     * or
     * {@link #respondWorkflowTaskFailed(String, int, String, Map, AmazonSimpleWorkflow)}
     * .
     * 
     * @param workflowTask
     *            The decision task to handle. The reason for more then one task
     *            being received is pagination of the history. All tasks in the
     *            iterator contain the same information but different pages of
     *            the history. The tasks are loaded lazily when
     *            {@link Iterator#next()} is called. It is expected that the
     *            method implementation aborts decision by rethrowing any
     *            exception from {@link Iterator#next()}.
     */
    public abstract RespondDecisionTaskCompletedRequest handleDecisionTask(Iterator decisionTaskIterator) throws Exception;

    public abstract List getAsynchronousThreadDump(Iterator decisionTaskIterator) throws Exception;

    public abstract String getAsynchronousThreadDumpAsString(Iterator decisionTaskIterator) throws Exception;

    public abstract Object loadWorkflowThroughReplay(Iterator decisionTaskIterator) throws Exception;

}