/*
   * The contents of this file are subject to the BT "ZEUS" Open Source 
   * Licence (L77741), Version 1.0 (the "Licence"); you may not use this file 
   * except in compliance with the Licence. You may obtain a copy of the Licence
   * from $ZEUS_INSTALL/licence.html or alternatively from
   * http://www.labs.bt.com/projects/agents/zeus/licence.htm
   * 
   * Except as stated in Clause 7 of the Licence, software distributed under the
   * Licence is distributed WITHOUT WARRANTY OF ANY KIND, either express or 
  * implied. See the Licence for the specific language governing rights and 
  * limitations under the Licence.
  * 
  * The Original Code is within the package zeus.*.
  * The Initial Developer of the Original Code is British Telecommunications
  * public limited company, whose registered office is at 81 Newgate Street, 
  * London, EC1A 7AJ, England. Portions created by British Telecommunications 
  * public limited company are Copyright 1996-9. All Rights Reserved.
  * 
  * THIS NOTICE MUST BE INCLUDED ON ANY COPY OF THIS FILE
  */
  
  
  
  package zeus.gui.fields;
  
  import java.awt.Toolkit;
  import java.awt.event.*;
  import javax.swing.*;
  import javax.swing.text.*;
  import javax.swing.event.*;
  
  
  public class RealNumberField extends JTextField
                            implements FocusListener, DocumentListener  {
  
     protected static char MINUS = '-';
     protected static char PERIOD = '.';
     protected EventListenerList changeListeners = new EventListenerList();
     protected double min;
     protected double max;
     protected boolean range_check = false;
     protected boolean range_checked = false;
  
     public RealNumberField() {
        super();
     }
     public RealNumberField(double min, double max) {
        this();
        this.min = min;
        this.max = max;
        range_check = true;
        this.addFocusListener(this);
     }
  
     public void focusGained(FocusEvent evt) {
     }
     public void focusLost(FocusEvent evt) {
        if ( range_check && !range_checked ) {
           range_checked = true;
           try {
              double value = (Double.valueOf(getText())).doubleValue();
              if ( value < min || value > max ) {
                 errorMsg();
                 return;
              }
           }
           catch(NumberFormatException e) {
              errorMsg();
              return;
           }
        }
     }
  
     public void setText(Double obj) {
        setText(obj.toString());
     }
     public void setText(Integer obj) {
        setText(obj.toString());
     }
     public void setText(Long obj) {
        setText(obj.toString());
     }
  
     protected void errorMsg() {
        JOptionPane.showMessageDialog(this,
           "Illegal entry\nValue must be between " + min + " and " +
           max + " inclusive","Error", JOptionPane.ERROR_MESSAGE);
     }
  
     public void setValue(double value) {
        if ( range_check ) {
           if ( value < min || value > max ) {
              errorMsg();
              return;
           }
        }
        setText(Double.toString(value));
     }
  
    public Double getValue() {
       try {
          return new Double(getText());
       }
       catch(NumberFormatException e) {
          return null;
       }
    }
 
    public Double getValue(double def) {
       try {
          return new Double(getText());
       }
       catch(NumberFormatException e) {
          return new Double(def);
       }
    }
 
    protected Document createDefaultModel() {
       Document doc = new RealNumberFieldDocument();
       doc.addDocumentListener(this);
       return doc;
    }
 
    public void insertUpdate(DocumentEvent e) {
       range_checked = false;
       fireChanged();
    }
    public void removeUpdate(DocumentEvent e) {
       range_checked = false;
       fireChanged();
    }
    public void changedUpdate(DocumentEvent e) {
       range_checked = false;
       fireChanged();
    }
 
    static char[] numberSet = {
     '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'
    };
 
    class RealNumberFieldDocument extends PlainDocument {
       public void insertString(int offs, String str, AttributeSet a)
          throws BadLocationException {
 
          if ( str == null ) return;
          str = str.trim();
 
          int length = getLength();
          String buf = getText(0,offs) + str + getText(offs,length-offs);
          buf = buf.trim();
          char[] array = buf.toCharArray();
 
          if ( array.length > 0 ) {
             if ( array[0] != MINUS && !member(array[0],numberSet) &&
 	         array[0] != PERIOD ) {
                Toolkit.getDefaultToolkit().beep();
                return;
             }
          }
 
 	 boolean period_found = (array.length > 0 && array[0] == PERIOD);
 
          for(int i = 1; i < array.length; i++ ) {
             if ( !member(array[i],numberSet) ) {
                if ( !period_found && array[i] == PERIOD ) {
                   period_found = true;
                }
                else {
 	          Toolkit.getDefaultToolkit().beep();
                   return;
                }
             }
          }
          super.insertString(offs,str,a);
       }
    }
    static boolean member(char item, char[] array) {
       for(int i = 0; i < array.length; i++ )
          if ( array[i] == item ) return true;
       return false;
    }
    //------------------------------------------------------------------------
    // Event Methods
    //------------------------------------------------------------------------
 
    public void addChangeListener(ChangeListener x) {
       changeListeners.add(ChangeListener.class, x);
    }
 
    public void removeChangeListener(ChangeListener x) {
       changeListeners.remove(ChangeListener.class, x);
    }
 
    protected void fireChanged() {
       ChangeEvent c = new ChangeEvent(this);
       Object[] listeners = changeListeners.getListenerList();
       for(int i= listeners.length-2; i >= 0; i -=2) {
          if (listeners[i] == ChangeListener.class) {
             ChangeListener cl = (ChangeListener)listeners[i+1];
             cl.stateChanged(c);
          }
       }
    }
 }