bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/dialogs/IDEEditorsPreferencePage.java

/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.ui.internal.ide.dialogs;

import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.Collections;

import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.Preferences;

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.ModifyEvent;
import org.eclipse.swt.events.ModifyListener;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Combo;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Group;

import org.eclipse.ui.internal.dialogs.EditorsPreferencePage;
import org.eclipse.ui.internal.ide.IDEWorkbenchMessages;

/**
 * Extends the Editors preference page with IDE-specific settings.
 *
 * @issue want IDE settings to appear in main Editors preference page (via subclassing),
 *   however the superclass, EditorsPreferencePage, is internal
 */
public class IDEEditorsPreferencePage extends EditorsPreferencePage {

	// State for encoding group
	private String defaultEnc;
	private Button defaultEncodingButton;
	private Button otherEncodingButton;
	private Combo encodingCombo;
	
	protected Control createContents(Composite parent) {
		Composite composite = createComposite(parent);

		createEditorHistoryGroup(composite);
		
		createSpace(composite);
		createCloseEditorsOnExitPref(composite);
		createEditorReuseGroup(composite);
		
		createSpace(composite);
		createEncodingGroup(composite);
		
		updateValidState();

		// @issue need IDE-level help for this page
//		WorkbenchHelp.setHelp(parent, IHelpContextIds.WORKBENCH_EDITOR_PREFERENCE_PAGE);

		return composite;
	}
	

	private void createEncodingGroup(Composite parent) {
		
		Font font = parent.getFont();
		Group group = new Group(parent, SWT.NONE);
		GridData data = new GridData(GridData.FILL_HORIZONTAL);
		group.setLayoutData(data);
		GridLayout layout = new GridLayout();
		layout.numColumns = 2;
		group.setLayout(layout);
		group.setText(IDEWorkbenchMessages.getString("WorkbenchPreference.encoding")); //$NON-NLS-1$
		group.setFont(font);
		
		SelectionAdapter buttonListener = new SelectionAdapter() {
			public void widgetSelected(SelectionEvent e) {
				updateEncodingState(defaultEncodingButton.getSelection());
				updateValidState();
			}
		};
		
		defaultEncodingButton = new Button(group, SWT.RADIO);
		defaultEnc = System.getProperty("file.encoding", "UTF-8");  //$NON-NLS-1$  //$NON-NLS-2$
		defaultEncodingButton.setText(IDEWorkbenchMessages.format("WorkbenchPreference.defaultEncoding", new String[] { defaultEnc })); //$NON-NLS-1$
		data = new GridData();
		data.horizontalSpan = 2;
		defaultEncodingButton.setLayoutData(data);
		defaultEncodingButton.addSelectionListener(buttonListener);
		defaultEncodingButton.setFont(font);
		
		otherEncodingButton = new Button(group, SWT.RADIO);
		otherEncodingButton.setText(IDEWorkbenchMessages.getString("WorkbenchPreference.otherEncoding")); //$NON-NLS-1$
		otherEncodingButton.addSelectionListener(buttonListener);
		otherEncodingButton.setFont(font);
		
		encodingCombo = new Combo(group, SWT.NONE);
		data = new GridData();
		data.widthHint = convertWidthInCharsToPixels(15);
		encodingCombo.setFont(font);
		encodingCombo.setLayoutData(data);
		encodingCombo.addModifyListener(new ModifyListener() {
			public void modifyText(ModifyEvent e) {
				updateValidState();
			}
		});

		ArrayList encodings = new ArrayList();
		int n = 0;
		try {
			n = Integer.parseInt(IDEWorkbenchMessages.getString("WorkbenchPreference.numDefaultEncodings")); //$NON-NLS-1$
		}
		catch (NumberFormatException e) {
			// Ignore;
		}
		for (int i = 0; i < n; ++i) {
			String enc = IDEWorkbenchMessages.getString("WorkbenchPreference.defaultEncoding" + (i+1), null); //$NON-NLS-1$
			if (enc != null) {
				encodings.add(enc);
			}
		}
		
		if (!encodings.contains(defaultEnc)) {
			encodings.add(defaultEnc);
		}

		String enc = ResourcesPlugin.getPlugin().getPluginPreferences().getString(ResourcesPlugin.PREF_ENCODING);
		boolean isDefault = enc == null || enc.length() == 0;

		if (!isDefault && !encodings.contains(enc)) {
			encodings.add(enc);
		}
		Collections.sort(encodings);
		for (int i = 0; i < encodings.size(); ++i) {
			encodingCombo.add((String) encodings.get(i));
		}

		encodingCombo.setText(isDefault ? defaultEnc : enc);
		
		updateEncodingState(isDefault);
	}

	protected void updateValidState() {
		super.updateValidState();
		if (!isValid()) {
			return;
		}
		if (!isEncodingValid()) {
			setErrorMessage(IDEWorkbenchMessages.getString("WorkbenchPreference.unsupportedEncoding")); //$NON-NLS-1$
			setValid(false);
		}
	}
	
	private boolean isEncodingValid() {
		return defaultEncodingButton.getSelection() ||
		isValidEncoding(encodingCombo.getText());
	}
	
	private boolean isValidEncoding(String enc) {
		try {
			new String(new byte[0], enc);
			return true;
		} catch (UnsupportedEncodingException e) {
			return false;
		}
	}

	private void updateEncodingState(boolean useDefault) {
		defaultEncodingButton.setSelection(useDefault);
		otherEncodingButton.setSelection(!useDefault);
		encodingCombo.setEnabled(!useDefault);
		updateValidState();
	}		
	
	/**
	 * The default button has been pressed. 
	 */
	protected void performDefaults() {
		updateEncodingState(true);
		super.performDefaults();
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.ui.internal.dialogs.FileEditorsPreferencePage#performOk()
	 */
	public boolean performOk() {
		// set the workspace text file encoding
		Preferences resourcePrefs = ResourcesPlugin.getPlugin().getPluginPreferences();
		if (defaultEncodingButton.getSelection()) {
			resourcePrefs.setToDefault(ResourcesPlugin.PREF_ENCODING);
		}
		else {
			String enc = encodingCombo.getText();
			resourcePrefs.setValue(ResourcesPlugin.PREF_ENCODING, enc);
		}
		ResourcesPlugin.getPlugin().savePluginPreferences();

		return super.performOk();
	}
}