filehandler.java

编写程序

/*
 * @(#)FileHandler.java	1.5 03/12/19
 * 
 * Copyright (c) 2004 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * -Redistribution of source code must retain the above copyright notice, this
 *  list of conditions and the following disclaimer.
 * 
 * -Redistribution in binary form must reproduce the above copyright notice, 
 *  this list of conditions and the following disclaimer in the documentation
 *  and/or other materials provided with the distribution.
 * 
 * Neither the name of Sun Microsystems, Inc. or the names of contributors may 
 * be used to endorse or promote products derived from this software without 
 * specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any kind. ALL 
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
 * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
 * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MIDROSYSTEMS, INC. ("SUN")
 * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
 * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST 
 * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, 
 * INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY 
 * OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, 
 * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 * 
 * You acknowledge that this software is not designed, licensed or intended
 * for use in the design, construction, operation or maintenance of any
 * nuclear facility.
 */

import java.awt.*;
import java.awt.print.*;
import java.util.*;
import java.awt.geom.*;
import java.awt.font.*;
import javax.swing.text.*;

import javax.jnlp.FileOpenService;
import javax.jnlp.FileSaveService;
import javax.jnlp.PrintService;
import javax.jnlp.FileContents;
import javax.jnlp.ServiceManager;
import javax.jnlp.UnavailableServiceException;
import java.io.*;

public class FileHandler {
   
    static private FileOpenService _fos = null;
    static private FileSaveService _fss = null;
    static private PrintService _ps = null;
        
    static private FileContents _fc = null;
    
    static private JTextComponent editor = null;
    
    static public boolean isEnabled() {
	return true;
    }
    
    static public String open() {
	initialize();
	try {
	    _fc = _fos.openFileDialog(null, null);
	    return readFromFile(_fc);
	} catch(IOException ioe) {
	    ioe.printStackTrace(System.out);
	    return null;
	}
    };
    
    static public void save(String txt) {
	initialize();
	try {
	    // Show save dialog if no name is already given
	    if (_fc == null) {
		_fc = _fss.saveFileDialog(null, null, new StringBufferInputStream(txt), null);
		// file saved, done
		return;
	    }
	    // use this only when filename is known
	    if (_fc != null) {
		writeToFile(txt, _fc);
	    }
	} catch(IOException ioe) {
	    ioe.printStackTrace(System.out);
	    return;
	}
    };
    
    static public void saveAs(String txt) {
	initialize();
	try {
	    if (_fc == null) {
		// If not already saved. Save-as is like save
		save(txt);
		return;
	    } else {
		_fc = _fss.saveAsFileDialog(null, null, _fc);	
	    }
	} catch(IOException ioe) {
	    ioe.printStackTrace(System.out);
	    return;
	}
    };
    
    static public void print(JTextComponent textArea) {
        editor = textArea;

        // Creating printjob on a separate user thread
        // to workaround a known awt bug 4394889/4218471.
        // window does n't get repainted when print dialog displayed.

	new Thread() {
	    public void run() {
	        initialize();
	        try {
                    if (_ps != null) {
                    _ps.print(new WebpadPrinter());
                     return;
                    } 
	            } catch(Exception e) {
	             e.printStackTrace(System.out);
	             return;
	            }
	          }
	        }.start();
    }; 
 
    static private void writeToFile(String txt, FileContents fc) throws IOException {
	int sizeNeeded = txt.length() * 2;
	if (sizeNeeded  > fc.getMaxLength()) fc.setMaxLength(sizeNeeded);
	BufferedWriter os = new BufferedWriter(new OutputStreamWriter(_fc.getOutputStream(true)));
	os.write(txt);
	os.close();
    }
    
    static private String readFromFile(FileContents fc) throws IOException {
	if (fc == null) return null;
	BufferedReader br = new BufferedReader(new InputStreamReader(_fc.getInputStream()));
	StringBuffer sb = new StringBuffer((int)_fc.getLength());
	String line = br.readLine();
	while(line != null) {
	    sb.append(line);
	    sb.append("\n");
	    line = br.readLine();
	}
	br.close();
	return sb.toString();
    }
    
    static private synchronized void initialize() {
	if (_fss != null) return;
	try {
	    _fos = (FileOpenService)ServiceManager.lookup("javax.jnlp.FileOpenService");
	    _fss = (FileSaveService)ServiceManager.lookup("javax.jnlp.FileSaveService");
	    _ps = (PrintService)ServiceManager.lookup("javax.jnlp.PrintService");
	} catch(UnavailableServiceException e) {
           _fos = null;
           _fss = null;
           _ps = null;
	}
    }


static class WebpadPrinter implements Printable {

	public int print(Graphics g, PageFormat pageFormat,
	    int pageIndex) {
		Graphics2D g2d = (Graphics2D)g;

		try {
		return paintText(g2d, pageFormat, pageIndex);
		} catch (Exception e) {
			e.printStackTrace();
			return Printable.NO_SUCH_PAGE;
		 }
	        }

	int paintText(Graphics2D g2d, PageFormat pageFormat, 
            int pageIndex) throws Exception {
		String holdString;

		int pageImgHeight = (int)pageFormat.getImageableHeight();
		int pageHeight = (int)pageFormat.getHeight();
			
		g2d.translate(pageFormat.getImageableX(), pageFormat.getImageableY());
		g2d.setFont(editor.getGraphics().getFont());
		g2d.setColor(Color.black);

		String dispText = null;
		try {
		dispText = editor.getText(0, editor.getDocument().getLength());
		} catch (BadLocationException e) {
			throw new Exception(e.getMessage());
		}
		FontRenderContext frc = g2d.getFontRenderContext();
		Rectangle2D rect = g2d.getFont().getMaxCharBounds(frc);
		double charWidth = rect.getWidth();
		double charHeight = rect.getHeight() + 2.0d;
		double maxLineWidth = pageFormat.getImageableWidth();
		int maxCharsPerLine = (int)(maxLineWidth / (double)charWidth);

		String [] lines = getLines(dispText);

		int numLines = lines.length;
		double canvasHeight = charHeight * (double)numLines;
		int linesPerPage = (int)(pageImgHeight / charHeight);
		int numPages = numLines / linesPerPage + 1;

		int startLineNum = linesPerPage * pageIndex;

		int linesForThisPage = getNumLinesForPage(lines, pageIndex, linesPerPage);
		int endLineNum = startLineNum + linesForThisPage - 1;


		if (startLineNum >= lines.length) {
			return Printable.NO_SUCH_PAGE;
		}
			
		String [] linesToPrint = new String[linesForThisPage];

		System.arraycopy(lines, startLineNum, linesToPrint, 0, linesForThisPage);
			
		float y = 10.0f;
		LineMetrics lm = g2d.getFont().getLineMetrics("A", frc);
		double yinc = lm.getHeight() + 2.0;
		for (int i = 0; i<linesToPrint.length; i++) {	
			g2d.drawString(linesToPrint[i], 10.0f, y);
			y = (float)((double)y + yinc);
		}
		return Printable.PAGE_EXISTS;

	      }

	String [] getLines(String text) {
		// breaks string at '\n' into string array
		StringTokenizer st = new StringTokenizer(text,"\n",true);
		Vector v = new Vector();
		while(st.hasMoreTokens()) {

                /*
                ** This implementation is to workaround a know
                ** StringTokenizer bug 4140850 due to which 
                ** empty lines if any inside the document were not
                ** getting printed.
                */
                
                       String s = st.nextToken();
	               if (s.equals("\n")) {
			  v.add("");
	               } else {
			  v.add(s);
	                  if (st.hasMoreTokens())
		            st.nextToken(); // Skip '\n' separator
	               }
		}
		return (String [])v.toArray(new String[0]);
	}

     int getNumLinesForPage(String [] lines, int pageIndex, int linesPerPage) 
        {
	if (lines.length < (pageIndex + 1) * linesPerPage) {
		int val = lines.length - pageIndex * linesPerPage;
		return val;
	   } else {
		return linesPerPage;
	   }
	 }

				
   }
}