Chip 1998 November/Chip_1998-11_cd.bin/tema/Cafe/jfc.bin/TextPreview.java

Text File | 1998-02-26 | 5KB | 174 lines

/*
 * @(#)TextPreview.java    1.5 01/28/98
 *
 * Copyright (c) 1997 Sun Microsystems, Inc. All Rights Reserved.
 *
 * This software is the confidential and proprietary information of Sun
 * Microsystems, Inc. ("Confidential Information").  You shall not disclose
 * such Confidential Information and shall use it only in accordance with the
 * terms of the license agreement you entered into with Sun.
 *
 * SUN MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF THE
 * SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE,
 * OR NON-INFRINGEMENT. SUN SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY
 * LICENSEE AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR
 * ITS DERIVATIVES.
 *
 */

package com.sun.java.swing;

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import com.sun.java.swing.event.*;

/** A component to preview a text file, intended to fit into the
 *  preview slot of a FileChooser.  In normal usage, only the
 *  ask method is of interest: it pops up a dialog box with
 *  a FileChooser containing an instance of this previewer and
 *  filtering for appropriate files.
 *  @author James Gosling
 */
public class TextPreview extends Component implements FilePreview {
    private String txt[] = new String[10];
    private boolean blank;


    private static FileChooserFilter dfcf;

    /** Convenience method to prompt for the name of a text file.
    For example:
    <pre>File f = ImagePreview.ask(null,"Open file",previousFile,
                    null,new FileChooserFilter("Config file (cfg)"));
    </pre>
    @param fparent the parent frame for the dialog box.
        fparent may be null if a default parent has
        been established with StandardDialog
    @param description a description string that will be shown
        to the user to indicate what is being requested
    @param initial the initial value for the string
    @param columns the default width (in 'm's) of the TextField
    @param target the ChangeListener that will be informed if the
            OK or Apply buttons are hit.
    @param fcf    a FileChooserFilter for selecting the
            file names to be presented in the dialog box.
    @return If target is null,
        the dialog box will be modal and the method
        will return the final result, or null if canceled.
        Otherwise, the
        dialog box is non-modal, the method returns null
        immediatly, and the listener is informed when
        appropriate.  The source of the change event will
        be a FileChooser.
    @see StandardDialog
     */
    public static File ask(Component parent, String title, File dfc,
                    ChangeListener target,
                    FileChooserFilter fcf) {
    StandardDialog d;
    FileChooser c;
    if (dfcf == null && fcf == null) {
        dfcf = new FileChooserFilter();
        dfcf.add("Text file (txt,exc,dic)");
        dfcf.add("Hypertext file (html,htm)");
        dfcf.add("Java source (java)");
        dfcf.add("System file (ini,cfg,dat)");
        dfcf.add("C program (c,cpp)");
    }
    c = new FileChooser();
    c.setPreview(new TextPreview ());
    d = new StandardDialog(parent,
                   c, target == null);
    c.setFilter(fcf != null ? fcf : dfcf);
    if (dfc != null)
        c.getModel().setFile(dfc);
    if (title != null)
        d.setTitle(title);
    if (target != null)
        d.addChangeListener(target);
    d.start();
    return d.isCanceled() || target != null ? null
        : c.getModel().getFile();
    }

    public TextPreview () {
    }
    public void setPreviewFile(File f) {
    if (f == null) {
        if (!blank) {
        blank = true;
        repaint();
        }
        return;
    }
    blank = false;
    for (int i = txt.length; --i >= 0;)
        txt[i] = null;
    try {
        Reader in = new BufferedReader(new FileReader(f));
        char [] ln = new char[40];
        int c;
        int nc = 2000;
        int l = 0;
        int p = 0;
        while ((c = in.read()) >= 0 && --nc >= 0) {
        if (c == '\t')
            c = ' ';
        if ((c == '\n' || c == '\r') && p > 0) {
            if (p > ln.length)
            p = ln.length;
            String s = new String(ln, 0, p);
            if (!s.startsWith("//") && !s.startsWith("import")) {
            txt[l++] = s;
            if (l >= txt.length)
                break;
            }
            p = 0;
            continue;
        }
        if (c >= 0177 || c == 0) {
            blank = true;
            break;
        }
        if (c > 040 || c == 040 && p > 0)
            if (p < ln.length)
            ln[p++] = (char) c;
        }
        in.close();
    } catch(Throwable e) {
        txt[0] = "Error: " + e;
    }
    repaint();
    }
    private Dimension isize = new Dimension(120, 120);
    public void setSize(int w, int h) {
    if (w != isize.width || h != isize.height) {
        isize.width = w;
        isize.height = h;
        invalidate();
    }
    }
    public void setBounds(int x, int y, int width, int height) {
    super.setBounds(x, y, width, height);
    setSize(width, height);
    }
    public Dimension getPreferredSize() {
    return isize;
    }
    public Dimension getMinimumSize() {
    return getPreferredSize();
    }
    public void paint(Graphics g) {
    if (!blank) {
        FontMetrics fm = g.getFontMetrics();
        int y0 = fm.getAscent();
        int dy = fm.getHeight();
        for (int i = 0; i < txt.length; i++)
        if (txt[i] != null)
            g.drawString(txt[i], 0, i * dy + y0);
    }
    }
}