jtkeyboard.java

来自「Java Pattern Oriented Framework (Jt) 是为了」· Java 代码 · 共 162 行

package Jt;

import java.io.*;


/**
 *  Class used to receive input from
 *  the keyboard.
 */


public class JtKeyboard extends JtObject {


    private static final long serialVersionUID = 1L;
    public static final String JtCLASS_NAME = JtKeyboard.class.getName(); 
    String command = null;
    Process process = null;
    int status = 0;
    String stdout;
    String line = null;
    String prompt;


    /**
     * Specifies a prompt.
     */

    public void setPrompt (String prompt) {
        this.prompt = prompt;
    }

    /**
     * Returns the prompt.
     */

    public String getPrompt () {
        return (prompt);
    }

    private byte readln ()[] throws IOException {
        byte buffer[] ;
        int i;
        byte ch;

        buffer = new byte[1024];
        buffer[0] = '\0';

        i = 0;   
        while ((ch = (byte) System.in.read ()) >= 0) {
            if (i >= 1024)
                break;	


            buffer[i++] = ch;	
            if (ch == '\n') // check
                break;       

        }
        if (i == 0)
            line = null;
        else
            line = new String (buffer, 0, i);

        if (line != null)
            line = line.trim (); // check
        //System.out.println ("Line:" + i + ":" + line); 
        return buffer;

    }



    // activate: activate

    void activate () {
        //byte buffer[];

        if (prompt != null)
            System.out.print (prompt);

        try {
            readln ();  
            //buffer = readln ();
        } catch (IOException ex) {
            handleException (ex);
            //line = null;
            return; 
        }
        //line = new String (buffer);
        //System.out.println ("Line:" + line);    

    }


    /**
     * Process object messages.
     * <ul>
     * <li> JtACTIVATE - Read input from the keyboard
     * </ul>
     */

    public Object processMessage (Object message) {

        String msgid = null;
        //byte buffer[];
        //File file;
        JtMessage e = (JtMessage) message;

        if (e == null)
            return null;

        msgid = (String) e.getMsgId ();

        if (msgid == null)
            return null;

        // Remove this object
        if (msgid.equals (JtObject.JtREMOVE)) {
            return (null);     
        }

        if (msgid.equals (JtObject.JtACTIVATE)) {
            activate ();
            return (line);
        }

        return (super.processMessage(message));

    }


    /**
     * Demonstrates the messages processed by JtKeyBoard.
     */

    public static void main(String[] args) {

        JtObject main = new JtObject ();
        JtMessage msg;
        String oline;



        // main.setObjTrace (1);

        main.createObject (JtKeyboard.JtCLASS_NAME, "keyboard");
        msg = new JtMessage (JtObject.JtACTIVATE);
        //System.out.println ("Press any key to continue ...");
        main.setValue ("keyboard", "prompt", "Press any key to continue ...");
        oline = (String) main.sendMessage ("keyboard", msg);
        System.out.println ("Keyboard input:" + oline);
        main.removeObject ("keyboard");



    }
}