awtutilities.java

一个用java写的mail.里面的代码值得我们去研究！学习。

/*
** $Id: AWTUtilities.java,v 1.3 2001/05/07 12:34:45 kunugi Exp $
**
** Copyright (c) 2000-2001 Jeff Gay
** on behalf of ICEMail.org <http://www.icemail.org>
** Copyright (c) 1998-2000 by Timothy Gerard Endres
** 
** This program is free software.
** 
** You may redistribute it and/or modify it under the terms of the GNU
** General Public License as published by the Free Software Foundation.
** Version 2 of the license should be included with this distribution in
** the file LICENSE, as well as License.html. If the license is not
** included with this distribution, you may find a copy at the FSF web
** site at 'www.gnu.org' or 'www.fsf.org', or you may write to the
** Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139 USA.
**
** THIS SOFTWARE IS PROVIDED AS-IS WITHOUT WARRANTY OF ANY KIND,
** NOT EVEN THE IMPLIED WARRANTY OF MERCHANTABILITY. THE AUTHOR
** OF THIS SOFTWARE, ASSUMES _NO_ RESPONSIBILITY FOR ANY
** CONSEQUENCE RESULTING FROM THE USE, MODIFICATION, OR
** REDISTRIBUTION OF THIS SOFTWARE. 
*/

package org.icemail.util;

import java.awt.Component;
import java.awt.Container;
import java.awt.Dialog;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Image;
import java.awt.Insets;
import java.awt.Point;
import java.awt.Toolkit;

import java.awt.image.ImageProducer;

import java.io.IOException;

import java.net.URL;

import java.util.StringTokenizer;


/**
 * This is a class that contains useful utility functions related
 * to the Java AWT package.
 */
public class AWTUtilities
{
  static public Point
  centerDialogInParent( Dialog dialog, Component parent ) {
    Point parLoc = parent.getLocationOnScreen();

    Dimension parSz = parent.getSize();
    Dimension dlgSz = dialog.getSize();

    int x = parLoc.x + (parSz.width - dlgSz.width) / 2;
    int y = parLoc.y + (parSz.height - dlgSz.height) / 3;
    
    return new Point( x, y );
  }

  static public Point
  computeDialogLocation( Dialog dialog, int w, int h ) {
    Dimension scrnSz = dialog.getToolkit().getScreenSize();

    int x = (scrnSz.width - w) / 2;
    int y = (scrnSz.height - h) / 3;
    
    return new Point( x, y );
  }

  static public Point
  computeDialogLocation( Dialog dialog ) {
    Dimension dlgSz = dialog.getSize();
    Dimension scrnSz = dialog.getToolkit().getScreenSize();

    int x = (scrnSz.width - dlgSz.width) / 2;
    int y = (scrnSz.height - dlgSz.height) / 3;
    
    return new Point( x, y );
  }

  static public Point
  computeDialogLocation( Dialog dialog, Component rel ) {
    Dimension dlgSz = dialog.getSize();
    Dimension scrnSz = dialog.getToolkit().getScreenSize();

    int x = (scrnSz.width - dlgSz.width) / 2;
    int y = (scrnSz.height - dlgSz.height) / 3;
    
    if ( rel != null ) {
      Dimension relSz = rel.getSize();
      Point loc = rel.getLocationOnScreen();

      x = loc.x + ((relSz.width - dlgSz.width) / 2);

      y = loc.y + ((relSz.height - dlgSz.height) / 2);
    }

    if ( x < 0 ) x = 0;
    if ( y < 0 ) y = 0;

    return new Point( x, y );
  }

  static public void
  constrain( Container container, Component component,  
             int fill, int anchor,
             int gx, int gy, int gw, int gh, double wx, double wy ) {
    GridBagConstraints c = new GridBagConstraints();

    c.fill = fill;
    c.anchor = anchor;
    c.gridx = gx;
    c.gridy = gy;
    c.gridwidth = gw;
    c.gridheight = gh;
    c.weightx = wx;
    c.weighty = wy;

    ( (GridBagLayout)container.getLayout() ).setConstraints( component, c );

    container.add( component );
  }

  static public void
  constrain( Container container, Component component,  
             int fill, int anchor,
             int gx, int gy, int gw, int gh,
             double wx, double wy, Insets inset ) {
    GridBagConstraints c = new GridBagConstraints();

    c.fill = fill;
    c.anchor = anchor;
    c.gridx = gx;
    c.gridy = gy;
    c.gridwidth = gw;
    c.gridheight = gh;
    c.weightx = wx;
    c.weighty = wy;
    c.insets = inset;

    ( (GridBagLayout)container.getLayout() ).setConstraints( component, c );

    container.add( component );
  }

  static public void
  constrain( Container container, Component component,  
             int fill, int anchor,
             int gx, int gy, int gw, int gh,
             double wx, double wy,
             int ipadx, int ipady ) {
    GridBagConstraints c = new GridBagConstraints();

    c.fill = fill;
    c.anchor = anchor;
    c.gridx = gx;
    c.gridy = gy;
    c.gridwidth = gw;
    c.gridheight = gh;
    c.weightx = wx;
    c.weighty = wy;
    c.ipadx = ipadx;
    c.ipady = ipady;

    ( (GridBagLayout)container.getLayout() ).setConstraints( component, c );

    container.add( component );
  }

  static public Font
  getFont( String fontName ) {
    StringTokenizer toker = new StringTokenizer( fontName, "-", false );

    String sName = "Helvetica";
    String sStyle = "plain";
    String sSize = "12";

    int numTokes = toker.countTokens();
    boolean isok = true;

    try {
      if ( numTokes > 0 ) {
        sName = toker.nextToken();

        if ( numTokes == 2 ) {
          sSize = toker.nextToken();
        } else if ( numTokes == 3 ) {
          sStyle = toker.nextToken();
          sSize = toker.nextToken();
        }
      }
    } catch ( Exception ex ) {
      System.err.println( "Bad font specification '" + fontName + "' - " + ex.getMessage() );
      return null;
    }

    int style = (sStyle.equalsIgnoreCase( "plain" ) ) ? Font.PLAIN :
                  ( (sStyle.equalsIgnoreCase( "bold" ) ) ? Font.BOLD :
                    ( (sStyle.equalsIgnoreCase( "italic" ) ) ? Font.ITALIC :
                                                               (Font.BOLD + Font.ITALIC) ) );

    int size = Integer.parseInt( sSize );

    return new Font( sName, style, size );
  }

  // The subtlety in getResource() is that it uses the
  // Class loader of the class used to get the rousource.
  // This means that if you want to load a resource from
  // your JAR file, then you better use a class in the
  // JAR file.
  public static Image
  getImageResource( String name ) throws java.io.IOException {
    return AWTUtilities.getImageResource( AWTUtilities.class, name );
  }

  public static Image
  getImageResource( Class base, String name ) throws java.io.IOException {
    Image result = null;

    URL imageURL = base.getResource( name );

    if ( imageURL != null ) {
      Toolkit tk = Toolkit.getDefaultToolkit();

      result = tk.createImage( (ImageProducer) imageURL.getContent() );
    }
    return result;
  }

  public static Image
  getSystemImageResource( String name ) throws java.io.IOException {
    Image result = null;

    URL imageURL = ClassLoader.getSystemResource( name );
    if ( imageURL != null ) {
      Toolkit tk = Toolkit.getDefaultToolkit();

      result = tk.createImage( (ImageProducer) imageURL.getContent() );
    }
    return result;
  }

}