JavaViewer.java

/*******************************************************************************
 * Copyright (c) 2000, 2007 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.examples.javaviewer;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.text.MessageFormat;
import java.util.ResourceBundle;

import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.StyledText;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.ShellAdapter;
import org.eclipse.swt.events.ShellEvent;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.FileDialog;
import org.eclipse.swt.widgets.Menu;
import org.eclipse.swt.widgets.MenuItem;
import org.eclipse.swt.widgets.MessageBox;
import org.eclipse.swt.widgets.Shell;

/**
 */
public class JavaViewer {
	static ResourceBundle	resources	= ResourceBundle.getBundle("examples_javaviewer");

	public static void main(String[] args) {
		Display display = new Display();
		JavaViewer example = new JavaViewer();
		Shell shell = example.open(display);
		while (!shell.isDisposed())
			if (!display.readAndDispatch())
				display.sleep();
		display.dispose();
	}

	FileDialog		fileDialog;
	JavaLineStyler	lineStyler	= new JavaLineStyler();
	Shell			shell;

	StyledText		text;

	public Shell open(Display display) {
		createShell(display);
		createMenuBar();
		createStyledText();
		shell.setSize(500, 400);
		shell.open();
		return shell;
	}

	Menu createFileMenu() {
		Menu bar = shell.getMenuBar();
		Menu menu = new Menu(bar);
		MenuItem item;

		// Open
		item = new MenuItem(menu, SWT.PUSH);
		item.setText(JavaViewer.resources.getString("Open_menuitem"));
		item.setAccelerator(SWT.MOD1 + 'O');
		item.addSelectionListener(new SelectionAdapter() {
			public void widgetSelected(SelectionEvent event) {
				openFile();
			}
		});

		// Exit
		item = new MenuItem(menu, SWT.PUSH);
		item.setText(JavaViewer.resources.getString("Exit_menuitem"));
		item.addSelectionListener(new SelectionAdapter() {
			public void widgetSelected(SelectionEvent e) {
				menuFileExit();
			}
		});
		return menu;
	}

	void createMenuBar() {
		Menu bar = new Menu(shell, SWT.BAR);
		shell.setMenuBar(bar);

		MenuItem fileItem = new MenuItem(bar, SWT.CASCADE);
		fileItem.setText(JavaViewer.resources.getString("File_menuitem"));
		fileItem.setMenu(createFileMenu());

	}

	void createShell(Display display) {
		shell = new Shell(display);
		shell.setText(JavaViewer.resources.getString("Window_title"));
		GridLayout layout = new GridLayout();
		layout.numColumns = 1;
		shell.setLayout(layout);
		shell.addShellListener(new ShellAdapter() {
			public void shellClosed(ShellEvent e) {
				lineStyler.disposeColors();
				text.removeLineStyleListener(lineStyler);
			}
		});
	}

	void createStyledText() {
		text = new StyledText(shell, SWT.BORDER | SWT.MULTI | SWT.V_SCROLL | SWT.H_SCROLL);
		GridData spec = new GridData();
		spec.horizontalAlignment = GridData.FILL;
		spec.grabExcessHorizontalSpace = true;
		spec.verticalAlignment = GridData.FILL;
		spec.grabExcessVerticalSpace = true;
		text.setLayoutData(spec);
		text.addLineStyleListener(lineStyler);
		text.setEditable(false);
		Color bg = Display.getDefault().getSystemColor(SWT.COLOR_GRAY);
		text.setBackground(bg);
	}

	void displayError(String msg) {
		MessageBox box = new MessageBox(shell, SWT.ICON_ERROR);
		box.setMessage(msg);
		box.open();
	}

	void menuFileExit() {
		shell.close();
	}

	void open(String name) {
		final String textString;

		if (name == null || name.length() == 0)
			return;

		File file = new File(name);
		if (!file.exists()) {
			String message = MessageFormat.format(JavaViewer.resources.getString("Err_file_no_exist"),
					new String[] { file.getName() });
			displayError(message);
			return;
		}

		try {
			FileInputStream stream = new FileInputStream(file.getPath());
			try {
				Reader in = new BufferedReader(new InputStreamReader(stream));
				char[] readBuffer = new char[2048];
				StringBuffer buffer = new StringBuffer((int) file.length());
				int n;
				while ((n = in.read(readBuffer)) > 0)
					buffer.append(readBuffer, 0, n);
				textString = buffer.toString();
				stream.close();
			} catch (IOException e) {
				// Err_file_io
				String message = MessageFormat.format(JavaViewer.resources.getString("Err_file_io"),
						new String[] { file.getName() });
				displayError(message);
				return;
			}
		} catch (FileNotFoundException e) {
			String message = MessageFormat.format(JavaViewer.resources.getString("Err_not_found"), new String[] { file
					.getName() });
			displayError(message);
			return;
		}
		// Guard against superfluous mouse move events -- defer action until later
		Display display = text.getDisplay();
		display.asyncExec(new Runnable() {
			public void run() {
				text.setText(textString);
			}
		});

		// parse the block comments up front since block comments can go across
		// lines - inefficient way of doing this
		lineStyler.parseBlockComments(textString);
	}

	void openFile() {
		if (fileDialog == null)
			fileDialog = new FileDialog(shell, SWT.OPEN);

		fileDialog.setFilterExtensions(new String[] { "*.java", "*.*" });
		String name = fileDialog.open();

		open(name);
	}
}