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

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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.ArrayList;
import java.util.List;

import com.amazonaws.services.simpleworkflow.model.HistoryEvent;

abstract class DecisionStateMachineBase implements DecisionStateMachine {

    protected DecisionState state = DecisionState.CREATED;

    protected List stateHistory = new ArrayList();

    private final DecisionId id;

    public DecisionStateMachineBase(DecisionId id) {
        this.id = id;
        stateHistory.add(state.toString());

    }

    /**
     * Used for unit testing.
     */
    protected DecisionStateMachineBase(DecisionId id, DecisionState state) {
        this.id = id;
        this.state = state;
        stateHistory.add(state.toString());
    }
    
    public DecisionState getState() {
        return state;
    }

    public DecisionId getId() {
        return id;
    }

    @Override
    public boolean isDone() {
        return state == DecisionState.COMPLETED || state == DecisionState.COMPLETED_AFTER_CANCELLATION_DECISION_SENT;
    }

    @Override
    public void handleDecisionTaskStartedEvent() {
        switch (state) {
        case CREATED:
            stateHistory.add("handleDecisionTaskStartedEvent");
            state = DecisionState.DECISION_SENT;
            stateHistory.add(state.toString());
            break;
        }
    }

    @Override
    public void cancel(Runnable immediateCancellationCallback) {
        stateHistory.add("cancel");
        switch (state) {
        case CREATED:
            state = DecisionState.COMPLETED;
            if (immediateCancellationCallback != null) {
                immediateCancellationCallback.run();
            }
            break;
        case DECISION_SENT:
            state = DecisionState.CANCELED_BEFORE_INITIATED;
            break;
        case INITIATED:
            state = DecisionState.CANCELED_AFTER_INITIATED;
            break;
        default:
            failStateTransition();
        }
        stateHistory.add(state.toString());
    }

    @Override
    public void handleInitiatedEvent(HistoryEvent event) {
        stateHistory.add("handleInitiatedEvent");
        switch (state) {
        case DECISION_SENT:
            state = DecisionState.INITIATED;
            break;
        case CANCELED_BEFORE_INITIATED:
            state = DecisionState.CANCELED_AFTER_INITIATED;
            break;
        default:
            failStateTransition();
        }
        stateHistory.add(state.toString());

    }

    @Override
    public void handleInitiationFailedEvent(HistoryEvent event) {
        stateHistory.add("handleInitiationFailedEvent");
        switch (state) {
        case DECISION_SENT:
        case CANCELED_BEFORE_INITIATED:
            state = DecisionState.COMPLETED;
            break;
        default:
            failStateTransition();
        }
        stateHistory.add(state.toString());

    }

    @Override
    public void handleStartedEvent(HistoryEvent event) {
        stateHistory.add("handleStartedEvent");
    }

    @Override
    public void handleCompletionEvent() {
        stateHistory.add("handleCompletionEvent");
        switch (state) {
        case CANCELED_AFTER_INITIATED:
        case INITIATED:
            state = DecisionState.COMPLETED;
            break;
        case CANCELLATION_DECISION_SENT:
            state = DecisionState.COMPLETED_AFTER_CANCELLATION_DECISION_SENT;
            break;
        default:
            failStateTransition();
        }
        stateHistory.add(state.toString());
    }

    @Override
    public void handleCancellationInitiatedEvent() {
        stateHistory.add("handleCancellationInitiatedEvent");
        switch (state) {
        case CANCELLATION_DECISION_SENT:
            // No state change
            break;
        default:
            failStateTransition();
        }
        stateHistory.add(state.toString());

    }

    @Override
    public void handleCancellationFailureEvent(HistoryEvent event) {
        stateHistory.add("handleCancellationFailureEvent");
        switch (state) {
        case COMPLETED_AFTER_CANCELLATION_DECISION_SENT:
            state = DecisionState.COMPLETED;
            break;
        default:
            failStateTransition();
        }
        stateHistory.add(state.toString());
    }

    @Override
    public void handleCancellationEvent() {
        stateHistory.add("handleCancellationEvent");
        switch (state) {
        case CANCELLATION_DECISION_SENT:
            state = DecisionState.COMPLETED;
            break;
        default:
            failStateTransition();
        }
        stateHistory.add(state.toString());

    }

    @Override
    public String toString() {
        return "DecisionStateMachineBase [id=" + id + ", state=" + state + ", isDone()=" + isDone() + ", stateHistory="
                + stateHistory + "]";
    }

    protected void failStateTransition() {
        throw new IllegalStateException("id=" + id + ", transitions=" + stateHistory);
    }

}