jtstate.java

来自「Java Pattern Oriented Framework (Jt) 是为了」· Java 代码 · 共 106 行

package Jt;

/**
 * Jt Implementation of the State pattern.
 */

public class JtState extends JtObject {

    public static final String JtCLASS_NAME = JtState.class.getName(); 
    private static final long serialVersionUID = 1L;
    private Object concreteState;


    public JtState () {
    }

    /**
     * Specifies the concrete state.
     *
     * @param state state
     */

    public void setConcreteState (Object state) {
        this.concreteState = state; 

    }

    /**
     * Returns the concrete state.
     */

    public Object getConcreteState () {
        return (concreteState);
    }


    /**
     * Process object messages.
     * <ul>
     * </ul>
     */

    public Object processMessage (Object event) {

        String msgid = null;
        JtMessage e = (JtMessage) event;
        //Object content;
        //Object data;


        if (e == null)
            return null;

        msgid = (String) e.getMsgId ();

        if (msgid == null)
            return null;

        //content = e.getMsgContent();
        //data = e.getMsgData ();

        //return (super.processMessage (event));


        if (msgid.equals (JtObject.JtREMOVE)) {
            return (null);     
        }

        if (concreteState == null) {
            handleError ("processMessage: concreteState attribute must be set");
            return (null);
        }

        return (((JtInterface) concreteState).processMessage (event));

    }


    /**
     * Demonstrates the messages processed by JtState
     */

    public static void main(String[] args) {

        JtFactory factory = new JtFactory ();
        JtState state;


        // Create an instance of JtState

        state = (JtState) factory.createObject (JtState.JtCLASS_NAME, "state");


        // Remove the object

        factory.removeObject (state);


    }

}