# EasyFSM - A Java Library to facilitate Finite State Machine (FSM) creation. ## Contents

Description

To build

To Use Library

Usage

## Description

This library facilitates creation of a Finite State Machine (FSM). Library generates a Finite State Machine (FSM) from a configuration file specified while invoking the object for the FSM class.

Current library has been built as Java Library Project in Netbeans 7.0.1

## To build

Source code (EasyFSM.zip) can be extracted and built in a Netbeans IDE or can even be ported to an Eclipse environment.

## To Use Library

Add EasyFSM.jar to the Java Library folder of your project or Java Installation. Ensure that the CLASSPATH variable of your build environment has the EasyFSM.jar in its path.

## Usage

Just a test example for usage (Example1.java):

/**
 * Example1 Code exemplifies the usage of FSM with a fixed path XML configuration file 
 **/
import Action.FSMAction;
import FSM.FSM;

public class Example1 {
    public static void testFSM() {
        try {
            FSM f = new FSM("C://config.xml", new FSMAction() {
                @Override
                public boolean action(String curState, String message, String nextState, Object args) {
                    javax.swing.JOptionPane.showMessageDialog(null, curState + ":" + message + " : " + nextState);
                    /*
                     * Here we can implement our login of how we wish to handle
                     * an action
                     */
                    return true;
                }
            });
            System.out.println(f.getCurrentState());
            f.ProcessFSM("MOVELEFT");
            System.out.println(f.getCurrentState());
            f.ProcessFSM("MOVE");
            System.out.println(f.getCurrentState());
            f.ProcessFSM("MOVERIGHT");
            System.out.println(f.getCurrentState());
        } catch (ParserConfigurationException ex) {
            Logger.getLogger(TestOwnCode.class.getName()).log(Level.SEVERE, null, ex);
        } catch (SAXException ex) {
            Logger.getLogger(TestOwnCode.class.getName()).log(Level.SEVERE, null, ex);
        } catch (IOException ex) {
            Logger.getLogger(TestOwnCode.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    public static void main(String[] args) {
        try {
            testFSM();
        } catch (Exception ex) {
            Logger.getLogger(TestOwnCode.class.getName()).log(Level.SEVERE, null, ex);
        }
    }
} 

Another example (Example2.java):

/**
 * Example2 Code exemplifies the usage of FSM with a XML configuration file specified
 * within the project as resource.
 **/
import Action.FSMAction;
import FSM.FSM;

public class Example2 {

    private String _configFileName = "resource/config.xml";

    public static void testFSM() {
        try {
            FSM f = new FSM(this.getClass().getClassLoader().getResourceAsStream(_configFileName), new FSMAction() {
                @Override
                public boolean action(String curState, String message, String nextState, Object args) {
                    javax.swing.JOptionPane.showMessageDialog(null, curState + ":" + message + " : " + nextState);
                    /*
                     * Here we can implement our login of how we wish to handle
                     * an action
                     */
                    return true;
                }
            });
            System.out.println(f.getCurrentState());
            f.ProcessFSM("MOVELEFT");
            System.out.println(f.getCurrentState());
            f.ProcessFSM("MOVE");
            System.out.println(f.getCurrentState());
            f.ProcessFSM("MOVERIGHT");
            System.out.println(f.getCurrentState());
        } catch (ParserConfigurationException ex) {
            Logger.getLogger(TestOwnCode.class.getName()).log(Level.SEVERE, null, ex);
        } catch (SAXException ex) {
            Logger.getLogger(TestOwnCode.class.getName()).log(Level.SEVERE, null, ex);
        } catch (IOException ex) {
            Logger.getLogger(TestOwnCode.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    public static void main(String[] args) {
        try {
            testFSM();
        } catch (Exception ex) {
            Logger.getLogger(TestOwnCode.class.getName()).log(Level.SEVERE, null, ex);
        }
    }
}

XML Configuration file should be of the following format:

<?xml version="1.0" encoding="UTF-8"?>

<!--
    Document   : config.xml
    Created on : 22 March, 2013, 9:05 AM
    Author     : ANKIT
    Description:
        File specifies states and transition of an FSM.
        This is an example file.
-->

<FSM>
        <STATE id="START" type="ID">
                <MESSAGE id="MOVE" action="move" nextState="START" />
                <MESSAGE id="MOVELEFT" action="moveLeft" nextState="INTERMEDIATE" />
                <MESSAGE id="MOVERIGHT" action="moveRight" nextState="STOP" />
        </STATE>
        <STATE id="INTERMEDIATE">
                <MESSAGE id="MOVELEFT" action="moveLeft" nextState="STOP" />
                <MESSAGE id="MOVERIGHT" action="moveRight" nextState="ANKIT" />
        </STATE>
        <STATE id="STOP" />
        <STATE id="ANKIT" />
</FSM>

And here is a diagram representing the transitions for this finite state machine: