environment.java2

形式文法分析JAVA工具包 本JAVA Applets程序提供对LL(1),LL(2)和LR(1)文法分析处理,用户可以输入任何满足条件的形式文法,通帮过系统的提示和帮助构造出相应文法的分析表,以及

      PrintJob pj = this.getToolkit().getPrintJob(this, "Print Screen", null);
      Graphics pg = pj.getGraphics();
      this.printComponents(pg);
      pg.dispose();
      pj.end();
      updateStatus("Print completed.");
    } catch (Exception e) {
      updateStatus("");
      if(e.getMessage() !=null) {     //cancel button 
	DFAOKDialog dg = new DFAOKDialog("Could not print current machine.\n"+ e.getMessage(), 
				   this, "DFA Print Error");
	dg.show();
      }
    }
  }
  
  /**
   * Opens a dialog and focuses the nondeterministic states.
   * These are found by calling showNondets from Machine.
   * @see	Machine
   */
  public void  showNondets() {
    String error = a.checkMachine();
    if (error == null)
      if (a.showNondets()) {
        a.d.repaint();
        DFAOKDialog dg = new DFAOKDialog("The nondeterministic states\nare highlighted.",
        	this, "DFA Message");
        Thread dt = Thread.currentThread();
        dg.setDialogThread(dt);
        dg.show();

        if (dg.getPushedButton().equals(ThreadDialog.NOT_YET))
          dt.suspend();   
        a.d.unfocusAll();
        a.d.repaint();
      } else {
        DFAOKDialog dg = new DFAOKDialog(AUTOMATON_IS_DETER_STR, this,"DFA Message");
        dg.show();
      }
    else {
      DFAOKDialog dg = new DFAOKDialog(error, this, "DFA Error");
      dg.show();
    }    
  }

  /**
    * Checks if the machine is deterministic or has any errors and returns an appropriate String.
    */
  public String checkDeterministic() {
      String error = a.checkMachine();
      if (error != null )
	return error;
      if (a.showNondets() == false)
	return AUTOMATON_IS_DETER_STR;
       a.d.unfocusAll();
       a.d.repaint();
      return AUTOMATON_IS_NON_DETER_STR;
    }

  /**
    * sets the FSA to be a DFA builder
    */
  public void setToDfa(Vector theStates) {
    
    Desktop temp = new Desktop(Machine.FSA, this);
    dfa = new FSA(temp);
    dfa.buildDfa(theStates);
    d.setRowSize(dfa.d.theStates);
    dfa.d.setRowSize(dfa.d.theStates);
    d.setChecker(dfa.d.theStates);
    dfa.d.setChecker(dfa.d.theStates); 

    updateStatus("Mail any bugs or comments to: [e-mail]");
  }

  /**
    * Sets the source Environment that generated this Environment
    */
  public void setEnvSource(Environment source) {
    envSource = source;
  }

  /**
    * Sets the Environment that is generated by this environment
    */
  public void setEnvTarget(Environment target) {
    envTarget = target;
    setEnabled(target == null);
  }

  public Environment getEnvSource() {
    return envSource;
  }

  /**
    * Show the answer to the DFA convertion problem
    */
  public void showAnswers() {
    if (dfa == null)
      return;

    Machine temp = a;
    a = new FSA(dfa);
    d = a.d;
    centerPanel.remove(temp.d);
    centerPanel.add("Center", d);
    temp.d.setVisible(false);
    d.setVisible(true);
    super.validate();
    ((FSA) a).placeAllStates(temp);
    d.repaint();
  }


  public void setShowing(boolean boo) {
    super.setShowing(boo);
    if(boo == false)
      d.setVisible(false);
  }

  /**
    * Handles the checking to see if DFA and NFA are identical
    */
  public void done() {
    String erro;

    if (dfa == null)
      return;

    d.unmarkAllStates();
    dfa.d.unmarkAllStates();
    d.unselectTransitions();

    erro = checkDeterministic();
    if(erro != AUTOMATON_IS_DETER_STR) {  
      a.showNondets();
      if( erro.equals(AUTOMATON_IS_NON_DETER_STR))
	erro = "The highlighted state(s) are nondeterministic";
      DFAOKDialog dg = new DFAOKDialog(erro, this, "Automaton check.");
      dg.show(); 
    } else if(checkMultiLetterLabels()) {
      erro = "Your automaton should have no multiple \n letter transition labels.";
      DFAOKDialog dg = new DFAOKDialog(erro, this, "Automaton check.");
      dg.show(); 
    } else {
      erro = ((FSA) a).checkDfaDone(dfa);
      d.repaint();
      if(erro.equals(DFA_IS_CORRECT_STR)) {
	d.relabel();
	d.repaint();
	myGrammar.addOtherWindows();
	informWatcher("Next");
	return;
      }
      DFAOKDialog dg = new DFAOKDialog(erro, this, "Automaton check.");
      dg.show(); 
    }
    d.unfocusAll();
    d.repaint();
    d.selectedState = null;
  }

  /**
    * Solves only the selected State in the NFA to DFA window
    */
  public void expandState(State s) {
    String answer = ((FSA) a).expandState(dfa, s);
    if(!answer.equals(DFA_IS_CORRECT_STR)) {
      DFAOKDialog dg = new DFAOKDialog(answer, this, "Expand State.");
      dg.show();
    }
    d.repaint();
  }
  
  /**
    * Check if any of the transitions have more than one letter.
    */
  public boolean checkMultiLetterLabels() {
    LabelSeparator breaker = new LabelSeparator((FSA) a);
    return breaker.checkMultiLetterLabels();
  }

  /**
    * Breaks up all multiple letter labels on the desktop into several states.
    */
  public void breakupMultipleLabels() {
    LabelSeparator breaker = new LabelSeparator((FSA) a);
    breaker.breakupMultipleLabels();
  }

  /**
   * Shows the states which are unreachable from
   * the initial state.
   */
  public void showUnreachables() {
     DFAOKDialog dg = new DFAOKDialog(a.showUnreachables(), this,"Unreachable States.");
     d.repaint();
     dg.show();
     d.unfocusAll();
     d.repaint();
  }

  public void showClosures(State s) {
    ((FSA)a).showClosures(s, dfa);
  }

  /**
   * Removes the current desktop and opens a brand new one.
   */
  public void clear() {
    centerPanel.remove(d);   
    d.setVisible(false);
    d = new Desktop(type, this);
        a = new FSA(d);
    centerPanel.add("Center", d);
    doLayout();
    updateStatus();
    d.setRowSize(dfa.d.theStates);
    d.setChecker(dfa.d.theStates);   
    d.setVisible(true);
    super.validate();
  }

  public void setEnabled(boolean b) {
    super.setEnabled(b);
    runmenu.setEnabled(b);
    filemenu.setEnabled(b);
    optionsmenu.setEnabled(b);
  }

  public void close() {
    this.setVisible(false);
  }
 
  /**
   * Updates the title and the status line.
   */
  public void updateStatus() {
    String typeInTitle = "DFA Window";
    this.setTitle(typeInTitle);
   
    String strModified = (a.d.modified) ? "(modified)":"";
    statusLine.setText("");
  }

  /**
   * Updates the title and the status line.
   * @param message	the new status line.
   */
  public int updateStatus(String message) {
    updateStatus();
    setMessage(message);
    setMessageSize(70);
    return 0;
  }

  /**
   * Should be removed when the bug regarding non-modal
   * dialogs is fixed.
   */
  public void threadAction(int id) {
    
    switch (id) {
    case CLOSE:
      close();
      break;
    case SHOWNONDETS:
      showNondets();
      break;
    }
  }  // end of method threadAction

}	// end of class Environment.