ExampleUsageMachineState.java

/**
 * This file is part of Waarp Project.
 * 
 * Copyright 2009, Frederic Bregier, and individual contributors by the @author tags. See the
 * COPYRIGHT.txt in the distribution for a full listing of individual contributors.
 * 
 * All Waarp Project is free software: you can redistribute it and/or modify it under the terms of
 * the GNU General Public License as published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 * 
 * Waarp is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
 * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
 * Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License along with Waarp . If not, see
 * <http://www.gnu.org/licenses/>.
 */
package org.waarp.common.state.example;

import java.util.EnumSet;
import java.util.concurrent.ConcurrentHashMap;

import org.waarp.common.exception.IllegalFiniteStateException;
import org.waarp.common.logging.WaarpLoggerFactory;
import org.waarp.common.logging.WaarpSlf4JLoggerFactory;
import org.waarp.common.state.MachineState;
import org.waarp.common.state.example.ExampleEnumState.ExampleTransition;

/**
 * Example of usage for MachineState based on ExampleEnumState enum class
 * 
 * @author Frederic Bregier
 * 
 */
public class ExampleUsageMachineState {
    /**
     * An example of usage.
     * 
     * @param args
     */
    @SuppressWarnings({
            "unchecked", "rawtypes" })
    public static void main(String[] args) {
        WaarpLoggerFactory.setDefaultFactory(new WaarpSlf4JLoggerFactory(null));

        // Example

        // First create a HashMap and fill it directly
        ConcurrentHashMap<ExampleEnumState, EnumSet<ExampleEnumState>> stateMap =
                new ConcurrentHashMap<ExampleEnumState, EnumSet<ExampleEnumState>>();
        stateMap.put(ExampleTransition.tRUNNING.elt.getState(),
                (EnumSet<ExampleEnumState>) ExampleTransition.tRUNNING.elt.getSet());
        // Second create the MachineState with the right Map
        MachineState<ExampleEnumState> machineState1 =
                new MachineState(ExampleEnumState.PAUSED, stateMap);
        // Third, if not already done, fill the Map with the transitions
        for (ExampleTransition trans : ExampleTransition.values()) {
            machineState1.addNewAssociation(trans.elt);
        }

        // Or First create the MachineSate but empty
        MachineState<ExampleEnumState> machineState2 =
                new MachineState(ExampleEnumState.PAUSED);
        // Second fill the associations with transitions since none exist yet
        for (ExampleTransition trans : ExampleTransition.values()) {
            machineState2.addNewAssociation(trans.elt);
        }

        System.out.println("Machine1 states...");
        changeState(machineState1, ExampleEnumState.CONFIGURING);
        changeState(machineState1, ExampleEnumState.PAUSED);
        changeState(machineState1, ExampleEnumState.RUNNING);
        changeState(machineState1, ExampleEnumState.ENDED);
        changeState(machineState1, ExampleEnumState.PAUSED);
        changeState(machineState1, ExampleEnumState.RESET);
        changeState(machineState1, ExampleEnumState.PAUSED);

        System.out.println("Machine2 states...");
        changeState(machineState2, ExampleEnumState.CONFIGURING);
        changeState(machineState2, ExampleEnumState.PAUSED);
        changeState(machineState2, ExampleEnumState.RUNNING);
        changeState(machineState2, ExampleEnumState.ENDED);
        changeState(machineState2, ExampleEnumState.PAUSED);
        changeState(machineState2, ExampleEnumState.RESET);
        changeState(machineState2, ExampleEnumState.PAUSED);
    }

    static private void changeState(MachineState<ExampleEnumState> mach,
            ExampleEnumState desired) {
        try {
            printState(mach);
            mach.setCurrent(desired);
            printState(mach);
        } catch (IllegalFiniteStateException e) {
            printWrongState(mach, desired);
        }
    }

    static private void printState(MachineState<ExampleEnumState> mach) {
        System.out.println("State is " + mach.getCurrent());
    }

    static private void printWrongState(MachineState<ExampleEnumState> mach,
            ExampleEnumState desired) {
        System.out.println("Cannot go from State " + mach.getCurrent() + " to State " + desired);
    }

}