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

Go to download

Show more of this group Show more artifacts with this name
Show all versions of aws-java-sdk Show documentation

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).

The newest version!

/*
 * 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 com.amazonaws.services.simpleworkflow.flow.DecisionContext;
import com.amazonaws.services.simpleworkflow.flow.DecisionContextProviderImpl;
import com.amazonaws.services.simpleworkflow.flow.WorkflowExecutionLocal;

/**
 * Holds DecisionContext for currently executing decision task. Do not use this
 * class directly. Instead use {@link DecisionContextProviderImpl}.
 */
public abstract class CurrentDecisionContext {

    private final static WorkflowExecutionLocal CURRENT = new WorkflowExecutionLocal();

    /**
     * retrieves the current DecisionContext for a particular thread
     * 
     * @return current decider context being used for the decision
     * @throws IllegalStateException
     *             if this method is called outside the scope of workflow
     *             definition.
     */
    public static DecisionContext get() {
        DecisionContext result = CURRENT.get();
        if (result == null) {
            throw new IllegalStateException(
                    "No context found. It means that the method is called outside of the workflow definition code.");
        }
        return result;
    }

    /**
     * @return if context is set which means that code is executed as part of
     *         the decision.
     */
    public static boolean isSet() {
        return CURRENT.get() != null;
    }

    public static void set(DecisionContext context) {
        if (context == null) {
            throw new IllegalArgumentException("null context");
        }
        WorkflowExecutionLocal.before();
        CURRENT.set(context);
    }

    public static void unset() {
        WorkflowExecutionLocal.after();
    }

}