plugins/org.eclipse.acceleo.ide.ui/src/org/eclipse/acceleo/internal/ide/ui/preferences/AcceleoEditorColoringPreferencePage.java - acceleo/org.eclipse.acceleo - Git at Google

 /*******************************************************************************
  * Copyright (c) 2011, 2012 Obeo.
  * 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:
  *     Obeo - initial API and implementation
  *******************************************************************************/
 package org.eclipse.acceleo.internal.ide.ui.preferences;

 import java.util.ArrayList;
 import java.util.List;

 import org.eclipse.acceleo.ide.ui.AcceleoUIActivator;
 import org.eclipse.acceleo.internal.ide.ui.AcceleoUIMessages;
 import org.eclipse.acceleo.internal.ide.ui.editors.template.AcceleoConfiguration;
 import org.eclipse.acceleo.internal.ide.ui.editors.template.color.AcceleoColor;
 import org.eclipse.acceleo.internal.ide.ui.editors.template.scanner.AcceleoPartitionScanner;
 import org.eclipse.core.runtime.Platform;
 import org.eclipse.core.runtime.preferences.DefaultScope;
 import org.eclipse.core.runtime.preferences.IEclipsePreferences;
 import org.eclipse.core.runtime.preferences.IEclipsePreferences.IPreferenceChangeListener;
 import org.eclipse.core.runtime.preferences.IEclipsePreferences.PreferenceChangeEvent;
 import org.eclipse.core.runtime.preferences.IPreferencesService;
 import org.eclipse.core.runtime.preferences.InstanceScope;
 import org.eclipse.jface.preference.PreferencePage;
 import org.eclipse.jface.resource.StringConverter;
 import org.eclipse.jface.text.Document;
 import org.eclipse.jface.text.IDocument;
 import org.eclipse.jface.text.IDocumentPartitioner;
 import org.eclipse.jface.text.rules.FastPartitioner;
 import org.eclipse.jface.text.source.SourceViewer;
 import org.eclipse.jface.viewers.IColorProvider;
 import org.eclipse.jface.viewers.ISelectionChangedListener;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.jface.viewers.ITreeContentProvider;
 import org.eclipse.jface.viewers.LabelProvider;
 import org.eclipse.jface.viewers.SelectionChangedEvent;
 import org.eclipse.jface.viewers.TreeViewer;
 import org.eclipse.jface.viewers.Viewer;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.DisposeEvent;
 import org.eclipse.swt.events.DisposeListener;
 import org.eclipse.swt.events.SelectionAdapter;
 import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.graphics.Color;
 import org.eclipse.swt.graphics.RGB;
 import org.eclipse.swt.layout.GridData;
 import org.eclipse.swt.layout.GridLayout;
 import org.eclipse.swt.widgets.Button;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Label;
 import org.eclipse.ui.IWorkbench;
 import org.eclipse.ui.IWorkbenchPreferencePage;
 import org.eclipse.ui.dialogs.PreferenceLinkArea;
 import org.eclipse.ui.preferences.IWorkbenchPreferenceContainer;

 /**
  * This page will provide the users a mean to change the colors of the Acceleo template editor, along with a
  * preview of the changes, import and export facilities...
  *
  * @author <a href="mailto:laurent.goubet@obeo.fr">Laurent Goubet</a>
  */
 public class AcceleoEditorColoringPreferencePage extends PreferencePage implements IWorkbenchPreferencePage {
 	/** Holds a reference to the preferences node providing default values for our preferences. */
 	private IEclipsePreferences defaultScope;

 	/** Holds a reference to the preferences node providing overridden values for our preferences. */
 	private IEclipsePreferences instanceScope;

 	/** This will be used as a proxy between the preference page and the instance scope. */
 	private ProxyPreferenceStore proxyScope;

 	/** This will keep a reference to the Tree viewer displaying the different available colors. */
 	private TreeViewer colorViewer;

 	/** List of the categories we are to display in the color viewer. */
 	private List<ColorCategory> colorCategories;

 	/** The button displayed in order to let users select their color. */
 	private ColorButton colorButton;

 	/**
 	 * {@inheritDoc}
 	 *
 	 * @see org.eclipse.ui.IWorkbenchPreferencePage#init(org.eclipse.ui.IWorkbench)
 	 */
 	public void init(IWorkbench workbench) {
 		defaultScope = new DefaultScope().getNode(AcceleoUIActivator.PLUGIN_ID);
 		instanceScope = new InstanceScope().getNode(AcceleoUIActivator.PLUGIN_ID);
 		proxyScope = new ProxyPreferenceStore(instanceScope, defaultScope);

 		AcceleoColor[] templateColors = new AcceleoColor[] {AcceleoColor.TEMPLATE,
 				AcceleoColor.TEMPLATE_NAME, AcceleoColor.TEMPLATE_PARAMETER,
 				AcceleoColor.TEMPLATE_OCL_EXPRESSION, AcceleoColor.TEMPLATE_OCL_KEYWORD, };
 		ColorCategory templateCategory = new ColorCategory(AcceleoColorMessages
 				.getString("org.eclipse.acceleo.template.category"), templateColors); //$NON-NLS-1$

 		AcceleoColor[] queryColors = new AcceleoColor[] {AcceleoColor.QUERY, AcceleoColor.QUERY_NAME,
 				AcceleoColor.QUERY_PARAMETER, AcceleoColor.QUERY_RETURN, };
 		ColorCategory queryCategory = new ColorCategory(AcceleoColorMessages
 				.getString("org.eclipse.acceleo.query.category"), queryColors); //$NON-NLS-1$

 		AcceleoColor[] generalColors = new AcceleoColor[] {AcceleoColor.COMMENT, AcceleoColor.MODULE_NAME,
 				AcceleoColor.FOR, AcceleoColor.IF, AcceleoColor.LET, AcceleoColor.DEFAULT,
 				AcceleoColor.KEYWORD, AcceleoColor.LITERAL, AcceleoColor.OCL_EXPRESSION,
 				AcceleoColor.OCL_KEYWORD, AcceleoColor.VARIABLE, AcceleoColor.PROTECTED_AREA, };
 		ColorCategory generalCategory = new ColorCategory(AcceleoColorMessages
 				.getString("org.eclipse.acceleo.general.category"), generalColors); //$NON-NLS-1$

 		colorCategories = new ArrayList<ColorCategory>();
 		colorCategories.add(templateCategory);
 		colorCategories.add(queryCategory);
 		colorCategories.add(generalCategory);
 	}

 	/**
 	 * {@inheritDoc}
 	 *
 	 * @see org.eclipse.jface.preference.PreferencePage#performDefaults()
 	 */
 	@Override
 	protected void performDefaults() {
 		super.performDefaults();
 		proxyScope.resetToDefault();
 	}

 	/**
 	 * {@inheritDoc}
 	 *
 	 * @see org.eclipse.jface.preference.PreferencePage#performOk()
 	 */
 	@Override
 	public boolean performOk() {
 		proxyScope.propagate();

 		return super.performOk();
 	}

 	/**
 	 * {@inheritDoc}
 	 *
 	 * @see org.eclipse.jface.preference.PreferencePage#createContents(org.eclipse.swt.widgets.Composite)
 	 */
 	@Override
 	protected Control createContents(Composite parent) {
 		// Link to the general color pages
 		final PreferenceLinkArea textEditorLink = new PreferenceLinkArea(parent, SWT.NONE,
 				"org.eclipse.ui.preferencePages.GeneralTextEditor", //$NON-NLS-1$
 				AcceleoUIMessages.getString("AcceleoEditorColoringPreferencePage.link"), //$NON-NLS-1$
 				(IWorkbenchPreferenceContainer)getContainer(), null);
 		final GridData linkGrid = new GridData();
 		linkGrid.grabExcessHorizontalSpace = true;
 		linkGrid.horizontalSpan = 3;
 		linkGrid.horizontalAlignment = GridData.FILL;
 		textEditorLink.getControl().setLayoutData(linkGrid);

 		Composite colorComposite = new Composite(parent, SWT.NONE);
 		colorComposite.setLayout(new GridLayout());

 		Label foregroundLabel = new Label(colorComposite, SWT.LEFT);
 		foregroundLabel.setText(AcceleoUIMessages
 				.getString("AcceleoEditorColoringPreferencePage.foreground.label") + ':'); //$NON-NLS-1$
 		foregroundLabel.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));

 		// Color list area
 		Composite preferenceEditComposite = new Composite(colorComposite, SWT.NONE);
 		GridLayout layout = new GridLayout();
 		layout.numColumns = 2;
 		layout.marginHeight = 0;
 		layout.marginWidth = 0;
 		preferenceEditComposite.setLayout(layout);
 		GridData gd = new GridData(GridData.FILL_BOTH);
 		preferenceEditComposite.setLayoutData(gd);

 		colorViewer = new TreeViewer(preferenceEditComposite, SWT.SINGLE | SWT.V_SCROLL | SWT.BORDER);
 		colorViewer.setLabelProvider(new ColorViewerLabelProvider());
 		colorViewer.setContentProvider(new ColorViewerContentProvider());
 		gd = new GridData(GridData.FILL_BOTH);
 		gd.heightHint = convertHeightInCharsToPixels(5);
 		colorViewer.getControl().setLayoutData(gd);
 		colorViewer.setInput(colorCategories);

 		// Color chooser area
 		Composite styleComposite = new Composite(preferenceEditComposite, SWT.NONE);
 		layout = new GridLayout();
 		layout.marginHeight = 0;
 		layout.marginWidth = 0;
 		layout.numColumns = 2;
 		styleComposite.setLayout(layout);
 		styleComposite.setLayoutData(new GridData(GridData.FILL_BOTH));

 		Label colorChoiceLabel = new Label(styleComposite, SWT.LEFT);
 		colorChoiceLabel.setText(AcceleoUIMessages
 				.getString("AcceleoEditorColoringPreferencePage.color.label") + ':'); //$NON-NLS-1$
 		gd = new GridData();
 		gd.horizontalAlignment = GridData.BEGINNING;
 		colorChoiceLabel.setLayoutData(gd);

 		colorButton = new ColorButton(styleComposite);
 		Button foregroundButton = colorButton.getButton();
 		foregroundButton.setEnabled(false);
 		gd = new GridData(GridData.FILL_HORIZONTAL);
 		gd.horizontalAlignment = GridData.BEGINNING;
 		foregroundButton.setLayoutData(gd);

 		// Preview Area
 		Label previewLabel = new Label(colorComposite, SWT.LEFT);
 		previewLabel
 				.setText(AcceleoUIMessages.getString("AcceleoEditorColoringPreferencePage.preview.label") + ':'); //$NON-NLS-1$
 		previewLabel.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));

 		Control previewEditor = createPreviewViewer(colorComposite);
 		gd = new GridData(GridData.FILL_BOTH);
 		final int widthHint = 20;
 		gd.widthHint = convertWidthInCharsToPixels(widthHint);
 		gd.heightHint = convertHeightInCharsToPixels(5);
 		previewEditor.setLayoutData(gd);

 		// Setting up listeners
 		colorViewer.addSelectionChangedListener(new ISelectionChangedListener() {
 			/**
 			 * {@inheritDoc}
 			 *
 			 * @see org.eclipse.jface.viewers.ISelectionChangedListener#selectionChanged(org.eclipse.jface.viewers.SelectionChangedEvent)
 			 */
 			public void selectionChanged(SelectionChangedEvent event) {
 				handleColorSelection();
 			}
 		});

 		foregroundButton.addSelectionListener(new SelectionAdapter() {
 			/**
 			 * {@inheritDoc}
 			 *
 			 * @see org.eclipse.swt.events.SelectionAdapter#widgetSelected(org.eclipse.swt.events.SelectionEvent)
 			 */
 			@Override
 			public void widgetSelected(SelectionEvent e) {
 				handleColorChange();
 			}
 		});

 		return colorComposite;
 	}

 	/**
 	 * This will be called from selection changes in the {@link #colorViewer}.
 	 */
 	private void handleColorSelection() {
 		IStructuredSelection selection = (IStructuredSelection)colorViewer.getSelection();
 		if (selection.getFirstElement() instanceof ColorItem) {
 			ColorItem colorItem = (ColorItem)selection.getFirstElement();
 			colorButton.getButton().setEnabled(true);
 			colorButton.setColorValue(getRGB(colorItem.getColor()));
 		} else {
 			colorButton.getButton().setEnabled(false);
 		}
 	}

 	/**
 	 * This will be called whenever the user changes one of the possible colors.
 	 */
 	private void handleColorChange() {
 		IStructuredSelection selection = (IStructuredSelection)colorViewer.getSelection();
 		if (selection.getFirstElement() instanceof ColorItem) {
 			ColorItem colorItem = (ColorItem)selection.getFirstElement();
 			RGB rgb = colorButton.getColorValue();
 			String rgbString = StringConverter.asString(rgb);
 			proxyScope.put(colorItem.getColor().getPreferenceKey(), rgbString);
 		}
 	}

 	/**
 	 * Retrieves the preference value corresponding to the given {@link AcceleoColor}.
 	 *
 	 * @param color
 	 *            {@link AcceleoColor} for which we need an RGB value.
 	 * @return The preference value corresponding to the given {@link AcceleoColor}.
 	 */
 	private RGB getRGB(AcceleoColor color) {
 		IPreferencesService service = Platform.getPreferencesService();
 		String defaultValue = StringConverter.asString(color.getDefault());

 		String value = service.get(color.getPreferenceKey(), defaultValue, getPreferenceLookupOrder());
 		RGB rgbValue = StringConverter.asRGB(value);

 		return rgbValue;
 	}

 	/**
 	 * Returns the order in which preferences should be looked up.
 	 *
 	 * @return The order in which preferences should be looked up.
 	 */
 	private IEclipsePreferences[] getPreferenceLookupOrder() {
 		return new IEclipsePreferences[] {proxyScope, instanceScope, defaultScope, };
 	}

 	/**
 	 * Creates the preview editor.
 	 *
 	 * @param parent
 	 *            Parent composite of this editor.
 	 * @return The preview editor.
 	 */
 	private Control createPreviewViewer(Composite parent) {
 		final SourceViewer previewViewer = new SourceViewer(parent, null, null, false, SWT.BORDER
 				| SWT.V_SCROLL | SWT.H_SCROLL);
 		final AcceleoConfiguration configuration = new AcceleoConfiguration(AcceleoUIActivator.getDefault()
 				.getPreferenceStore(), getPreferenceLookupOrder());

 		IDocument document = new Document();
 		previewViewer.setDocument(document);

 		previewViewer.configure(configuration);
 		previewViewer.setEditable(false);

 		String previewContent = AcceleoColorMessages.getString("editor.preview"); //$NON-NLS-1$
 		document.set(previewContent);

 		// Setup syntax highlighting and partitioning
 		IDocumentPartitioner partitioner = new FastPartitioner(new AcceleoPartitionScanner(),
 				AcceleoPartitionScanner.LEGAL_CONTENT_TYPES);
 		partitioner.connect(document);
 		document.setDocumentPartitioner(partitioner);

 		final IPreferenceChangeListener preferenceListener = new IPreferenceChangeListener() {
 			/**
 			 * {@inheritDoc}
 			 *
 			 * @see org.eclipse.core.runtime.preferences.IEclipsePreferences.IPreferenceChangeListener#preferenceChange(org.eclipse.core.runtime.preferences.IEclipsePreferences.PreferenceChangeEvent)
 			 */
 			public void preferenceChange(PreferenceChangeEvent event) {
 				configuration.adaptToPreferenceChanges(event);
 				previewViewer.invalidateTextPresentation();
 			}
 		};

 		proxyScope.addPreferenceChangeListener(preferenceListener);
 		previewViewer.getTextWidget().addDisposeListener(new DisposeListener() {
 			public void widgetDisposed(DisposeEvent e) {
 				proxyScope.removePreferenceChangeListener(preferenceListener);
 			}
 		});

 		return previewViewer.getControl();
 	}

 	/**
 	 * Label provider for our {@link #colorViewer}.
 	 *
 	 * @author <a href="mailto:laurent.goubet@obeo.fr">Laurent Goubet</a>
 	 */
 	private class ColorViewerLabelProvider extends LabelProvider implements IColorProvider {
 		/**
 		 * {@inheritDoc}
 		 *
 		 * @see org.eclipse.jface.viewers.IColorProvider#getBackground(java.lang.Object)
 		 */
 		public Color getBackground(Object element) {
 			return null;
 		}

 		/**
 		 * {@inheritDoc}
 		 *
 		 * @see org.eclipse.jface.viewers.IColorProvider#getForeground(java.lang.Object)
 		 */
 		public Color getForeground(Object element) {
 			return null;
 		}

 		/**
 		 * {@inheritDoc}
 		 *
 		 * @see org.eclipse.jface.viewers.LabelProvider#getText(java.lang.Object)
 		 */
 		@Override
 		public String getText(Object element) {
 			if (element instanceof ColorCategory) {
 				return ((ColorCategory)element).getName();
 			}
 			return ((ColorItem)element).getName();
 		}
 	}

 	/**
 	 * Content provider for our {@link #colorViewer}.
 	 *
 	 * @author <a href="mailto:laurent.goubet@obeo.fr">Laurent Goubet</a>
 	 */
 	private class ColorViewerContentProvider implements ITreeContentProvider {
 		/**
 		 * {@inheritDoc}
 		 *
 		 * @see org.eclipse.jface.viewers.ITreeContentProvider#getElements(java.lang.Object)
 		 */
 		@SuppressWarnings("unchecked")
 		public Object[] getElements(Object inputElement) {
 			if (inputElement instanceof List) {
 				List<ColorCategory> input = (List<ColorCategory>)inputElement;
 				return input.toArray(new ColorCategory[input.size()]);
 			}
 			return null;
 		}

 		/**
 		 * {@inheritDoc}
 		 *
 		 * @see org.eclipse.jface.viewers.ITreeContentProvider#getChildren(java.lang.Object)
 		 */
 		public Object[] getChildren(Object parentElement) {
 			if (parentElement instanceof ColorCategory) {
 				return ((ColorCategory)parentElement).getChildren();
 			}
 			return null;
 		}

 		/**
 		 * {@inheritDoc}
 		 *
 		 * @see org.eclipse.jface.viewers.ITreeContentProvider#getParent(java.lang.Object)
 		 */
 		public Object getParent(Object element) {
 			if (element instanceof ColorItem) {
 				return ((ColorItem)element).getCategory();
 			}
 			return null;
 		}

 		/**
 		 * {@inheritDoc}
 		 *
 		 * @see org.eclipse.jface.viewers.ITreeContentProvider#hasChildren(java.lang.Object)
 		 */
 		public boolean hasChildren(Object element) {
 			return element instanceof ColorCategory;
 		}

 		/**
 		 * {@inheritDoc}
 		 *
 		 * @see org.eclipse.jface.viewers.IContentProvider#inputChanged(org.eclipse.jface.viewers.Viewer,
 		 *      java.lang.Object, java.lang.Object)
 		 */
 		public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
 			// We do not need to react to input changes
 		}

 		/**
 		 * {@inheritDoc}
 		 *
 		 * @see org.eclipse.jface.viewers.IContentProvider#dispose()
 		 */
 		public void dispose() {
 			// Nothing to dispose
 		}
 	}

 	/**
 	 * Represents a category in the color viewer.
 	 *
 	 * @author <a href="mailto:laurent.goubet@obeo.fr">Laurent Goubet</a>
 	 */
 	private class ColorCategory {
 		/** List of this category's children. */
 		private final ColorItem[] children;

 		/** Human-readable name of this category. */
 		private final String displayName;

 		/**
 		 * Instantiates a Category given its children colors.
 		 *
 		 * @param displayName
 		 *            Display name of this category.
 		 * @param children
 		 *            The colors that are to be displayed as children of this category.
 		 */
 		public ColorCategory(String displayName, AcceleoColor[] children) {
 			this.displayName = displayName;
 			this.children = new ColorItem[children.length];
 			for (int i = 0; i < children.length; i++) {
 				this.children[i] = new ColorItem(this, children[i]);
 			}
 		}

 		/**
 		 * Returns the name of this category.
 		 *
 		 * @return The name of this category.
 		 */
 		public String getName() {
 			return displayName;
 		}

 		/**
 		 * Returns the children of this category.
 		 *
 		 * @return The children of this category.
 		 */
 		public ColorItem[] getChildren() {
 			return children;
 		}
 	}

 	/**
 	 * Wraps an {@link AcceleoColor} for our tree viewer.
 	 *
 	 * @author <a href="mailto:laurent.goubet@obeo.fr">Laurent Goubet</a>
 	 */
 	private class ColorItem {
 		/** Category in which this item is displayed. */
 		private final ColorCategory category;

 		/** The wrapped color. */
 		private final AcceleoColor color;

 		/**
 		 * Instantiates a tree item given its wrapped color.
 		 *
 		 * @param category
 		 *            The category this color belongs to.
 		 * @param color
 		 *            The color we are to wrap.
 		 */
 		public ColorItem(ColorCategory category, AcceleoColor color) {
 			this.category = category;
 			this.color = color;
 		}

 		/**
 		 * Returns the wrapped {@link AcceleoColor}.
 		 *
 		 * @return The wrapped {@link AcceleoColor}.
 		 */
 		public AcceleoColor getColor() {
 			return color;
 		}

 		/**
 		 * Returns the human-readable name for the wrapped color.
 		 *
 		 * @return The human-readable name for the wrapped color.
 		 */
 		public String getName() {
 			return AcceleoColorMessages.getString(color.getPreferenceKey());
 		}

 		/**
 		 * Returns the category in which this item is displayed.
 		 *
 		 * @return The category in which this item is displayed.
 		 */
 		public ColorCategory getCategory() {
 			return category;
 		}
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2011, 2012 Obeo.
	* 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:
	* Obeo - initial API and implementation
	*******************************************************************************/
	package org.eclipse.acceleo.internal.ide.ui.preferences;

	import java.util.ArrayList;
	import java.util.List;

	import org.eclipse.acceleo.ide.ui.AcceleoUIActivator;
	import org.eclipse.acceleo.internal.ide.ui.AcceleoUIMessages;
	import org.eclipse.acceleo.internal.ide.ui.editors.template.AcceleoConfiguration;
	import org.eclipse.acceleo.internal.ide.ui.editors.template.color.AcceleoColor;
	import org.eclipse.acceleo.internal.ide.ui.editors.template.scanner.AcceleoPartitionScanner;
	import org.eclipse.core.runtime.Platform;
	import org.eclipse.core.runtime.preferences.DefaultScope;
	import org.eclipse.core.runtime.preferences.IEclipsePreferences;
	import org.eclipse.core.runtime.preferences.IEclipsePreferences.IPreferenceChangeListener;
	import org.eclipse.core.runtime.preferences.IEclipsePreferences.PreferenceChangeEvent;
	import org.eclipse.core.runtime.preferences.IPreferencesService;
	import org.eclipse.core.runtime.preferences.InstanceScope;
	import org.eclipse.jface.preference.PreferencePage;
	import org.eclipse.jface.resource.StringConverter;
	import org.eclipse.jface.text.Document;
	import org.eclipse.jface.text.IDocument;
	import org.eclipse.jface.text.IDocumentPartitioner;
	import org.eclipse.jface.text.rules.FastPartitioner;
	import org.eclipse.jface.text.source.SourceViewer;
	import org.eclipse.jface.viewers.IColorProvider;
	import org.eclipse.jface.viewers.ISelectionChangedListener;
	import org.eclipse.jface.viewers.IStructuredSelection;
	import org.eclipse.jface.viewers.ITreeContentProvider;
	import org.eclipse.jface.viewers.LabelProvider;
	import org.eclipse.jface.viewers.SelectionChangedEvent;
	import org.eclipse.jface.viewers.TreeViewer;
	import org.eclipse.jface.viewers.Viewer;
	import org.eclipse.swt.SWT;
	import org.eclipse.swt.events.DisposeEvent;
	import org.eclipse.swt.events.DisposeListener;
	import org.eclipse.swt.events.SelectionAdapter;
	import org.eclipse.swt.events.SelectionEvent;
	import org.eclipse.swt.graphics.Color;
	import org.eclipse.swt.graphics.RGB;
	import org.eclipse.swt.layout.GridData;
	import org.eclipse.swt.layout.GridLayout;
	import org.eclipse.swt.widgets.Button;
	import org.eclipse.swt.widgets.Composite;
	import org.eclipse.swt.widgets.Control;
	import org.eclipse.swt.widgets.Label;
	import org.eclipse.ui.IWorkbench;
	import org.eclipse.ui.IWorkbenchPreferencePage;
	import org.eclipse.ui.dialogs.PreferenceLinkArea;
	import org.eclipse.ui.preferences.IWorkbenchPreferenceContainer;

	/**
	* This page will provide the users a mean to change the colors of the Acceleo template editor, along with a
	* preview of the changes, import and export facilities...
	*
	* @author <a href="mailto:laurent.goubet@obeo.fr">Laurent Goubet</a>
	*/
	public class AcceleoEditorColoringPreferencePage extends PreferencePage implements IWorkbenchPreferencePage {
	/** Holds a reference to the preferences node providing default values for our preferences. */
	private IEclipsePreferences defaultScope;

	/** Holds a reference to the preferences node providing overridden values for our preferences. */
	private IEclipsePreferences instanceScope;

	/** This will be used as a proxy between the preference page and the instance scope. */
	private ProxyPreferenceStore proxyScope;

	/** This will keep a reference to the Tree viewer displaying the different available colors. */
	private TreeViewer colorViewer;

	/** List of the categories we are to display in the color viewer. */
	private List<ColorCategory> colorCategories;

	/** The button displayed in order to let users select their color. */
	private ColorButton colorButton;

	/**
	* {@inheritDoc}
	*
	* @see org.eclipse.ui.IWorkbenchPreferencePage#init(org.eclipse.ui.IWorkbench)
	*/
	public void init(IWorkbench workbench) {
	defaultScope = new DefaultScope().getNode(AcceleoUIActivator.PLUGIN_ID);
	instanceScope = new InstanceScope().getNode(AcceleoUIActivator.PLUGIN_ID);
	proxyScope = new ProxyPreferenceStore(instanceScope, defaultScope);

	AcceleoColor[] templateColors = new AcceleoColor[] {AcceleoColor.TEMPLATE,
	AcceleoColor.TEMPLATE_NAME, AcceleoColor.TEMPLATE_PARAMETER,
	AcceleoColor.TEMPLATE_OCL_EXPRESSION, AcceleoColor.TEMPLATE_OCL_KEYWORD, };
	ColorCategory templateCategory = new ColorCategory(AcceleoColorMessages
	.getString("org.eclipse.acceleo.template.category"), templateColors); //$NON-NLS-1$

	AcceleoColor[] queryColors = new AcceleoColor[] {AcceleoColor.QUERY, AcceleoColor.QUERY_NAME,
	AcceleoColor.QUERY_PARAMETER, AcceleoColor.QUERY_RETURN, };
	ColorCategory queryCategory = new ColorCategory(AcceleoColorMessages
	.getString("org.eclipse.acceleo.query.category"), queryColors); //$NON-NLS-1$

	AcceleoColor[] generalColors = new AcceleoColor[] {AcceleoColor.COMMENT, AcceleoColor.MODULE_NAME,
	AcceleoColor.FOR, AcceleoColor.IF, AcceleoColor.LET, AcceleoColor.DEFAULT,
	AcceleoColor.KEYWORD, AcceleoColor.LITERAL, AcceleoColor.OCL_EXPRESSION,
	AcceleoColor.OCL_KEYWORD, AcceleoColor.VARIABLE, AcceleoColor.PROTECTED_AREA, };
	ColorCategory generalCategory = new ColorCategory(AcceleoColorMessages
	.getString("org.eclipse.acceleo.general.category"), generalColors); //$NON-NLS-1$

	colorCategories = new ArrayList<ColorCategory>();
	colorCategories.add(templateCategory);
	colorCategories.add(queryCategory);
	colorCategories.add(generalCategory);
	}

	/**
	* {@inheritDoc}
	*
	* @see org.eclipse.jface.preference.PreferencePage#performDefaults()
	*/
	@Override
	protected void performDefaults() {
	super.performDefaults();
	proxyScope.resetToDefault();
	}

	/**
	* {@inheritDoc}
	*
	* @see org.eclipse.jface.preference.PreferencePage#performOk()
	*/
	@Override
	public boolean performOk() {
	proxyScope.propagate();

	return super.performOk();
	}

	/**
	* {@inheritDoc}
	*
	* @see org.eclipse.jface.preference.PreferencePage#createContents(org.eclipse.swt.widgets.Composite)
	*/
	@Override
	protected Control createContents(Composite parent) {
	// Link to the general color pages
	final PreferenceLinkArea textEditorLink = new PreferenceLinkArea(parent, SWT.NONE,
	"org.eclipse.ui.preferencePages.GeneralTextEditor", //$NON-NLS-1$
	AcceleoUIMessages.getString("AcceleoEditorColoringPreferencePage.link"), //$NON-NLS-1$
	(IWorkbenchPreferenceContainer)getContainer(), null);
	final GridData linkGrid = new GridData();
	linkGrid.grabExcessHorizontalSpace = true;
	linkGrid.horizontalSpan = 3;
	linkGrid.horizontalAlignment = GridData.FILL;
	textEditorLink.getControl().setLayoutData(linkGrid);

	Composite colorComposite = new Composite(parent, SWT.NONE);
	colorComposite.setLayout(new GridLayout());

	Label foregroundLabel = new Label(colorComposite, SWT.LEFT);
	foregroundLabel.setText(AcceleoUIMessages
	.getString("AcceleoEditorColoringPreferencePage.foreground.label") + ':'); //$NON-NLS-1$
	foregroundLabel.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));

	// Color list area
	Composite preferenceEditComposite = new Composite(colorComposite, SWT.NONE);
	GridLayout layout = new GridLayout();
	layout.numColumns = 2;
	layout.marginHeight = 0;
	layout.marginWidth = 0;
	preferenceEditComposite.setLayout(layout);
	GridData gd = new GridData(GridData.FILL_BOTH);
	preferenceEditComposite.setLayoutData(gd);

	colorViewer = new TreeViewer(preferenceEditComposite, SWT.SINGLE \| SWT.V_SCROLL \| SWT.BORDER);
	colorViewer.setLabelProvider(new ColorViewerLabelProvider());
	colorViewer.setContentProvider(new ColorViewerContentProvider());
	gd = new GridData(GridData.FILL_BOTH);
	gd.heightHint = convertHeightInCharsToPixels(5);
	colorViewer.getControl().setLayoutData(gd);
	colorViewer.setInput(colorCategories);

	// Color chooser area
	Composite styleComposite = new Composite(preferenceEditComposite, SWT.NONE);
	layout = new GridLayout();
	layout.marginHeight = 0;
	layout.marginWidth = 0;
	layout.numColumns = 2;
	styleComposite.setLayout(layout);
	styleComposite.setLayoutData(new GridData(GridData.FILL_BOTH));

	Label colorChoiceLabel = new Label(styleComposite, SWT.LEFT);
	colorChoiceLabel.setText(AcceleoUIMessages
	.getString("AcceleoEditorColoringPreferencePage.color.label") + ':'); //$NON-NLS-1$
	gd = new GridData();
	gd.horizontalAlignment = GridData.BEGINNING;
	colorChoiceLabel.setLayoutData(gd);

	colorButton = new ColorButton(styleComposite);
	Button foregroundButton = colorButton.getButton();
	foregroundButton.setEnabled(false);
	gd = new GridData(GridData.FILL_HORIZONTAL);
	gd.horizontalAlignment = GridData.BEGINNING;
	foregroundButton.setLayoutData(gd);

	// Preview Area
	Label previewLabel = new Label(colorComposite, SWT.LEFT);
	previewLabel
	.setText(AcceleoUIMessages.getString("AcceleoEditorColoringPreferencePage.preview.label") + ':'); //$NON-NLS-1$
	previewLabel.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));

	Control previewEditor = createPreviewViewer(colorComposite);
	gd = new GridData(GridData.FILL_BOTH);
	final int widthHint = 20;
	gd.widthHint = convertWidthInCharsToPixels(widthHint);
	gd.heightHint = convertHeightInCharsToPixels(5);
	previewEditor.setLayoutData(gd);

	// Setting up listeners
	colorViewer.addSelectionChangedListener(new ISelectionChangedListener() {
	/**
	* {@inheritDoc}
	*
	* @see org.eclipse.jface.viewers.ISelectionChangedListener#selectionChanged(org.eclipse.jface.viewers.SelectionChangedEvent)
	*/
	public void selectionChanged(SelectionChangedEvent event) {
	handleColorSelection();
	}
	});

	foregroundButton.addSelectionListener(new SelectionAdapter() {
	/**
	* {@inheritDoc}
	*
	* @see org.eclipse.swt.events.SelectionAdapter#widgetSelected(org.eclipse.swt.events.SelectionEvent)
	*/
	@Override
	public void widgetSelected(SelectionEvent e) {
	handleColorChange();
	}
	});

	return colorComposite;
	}

	/**
	* This will be called from selection changes in the {@link #colorViewer}.
	*/
	private void handleColorSelection() {
	IStructuredSelection selection = (IStructuredSelection)colorViewer.getSelection();
	if (selection.getFirstElement() instanceof ColorItem) {
	ColorItem colorItem = (ColorItem)selection.getFirstElement();
	colorButton.getButton().setEnabled(true);
	colorButton.setColorValue(getRGB(colorItem.getColor()));
	} else {
	colorButton.getButton().setEnabled(false);
	}
	}

	/**
	* This will be called whenever the user changes one of the possible colors.
	*/
	private void handleColorChange() {
	IStructuredSelection selection = (IStructuredSelection)colorViewer.getSelection();
	if (selection.getFirstElement() instanceof ColorItem) {
	ColorItem colorItem = (ColorItem)selection.getFirstElement();
	RGB rgb = colorButton.getColorValue();
	String rgbString = StringConverter.asString(rgb);
	proxyScope.put(colorItem.getColor().getPreferenceKey(), rgbString);
	}
	}

	/**
	* Retrieves the preference value corresponding to the given {@link AcceleoColor}.
	*
	* @param color
	* {@link AcceleoColor} for which we need an RGB value.
	* @return The preference value corresponding to the given {@link AcceleoColor}.
	*/
	private RGB getRGB(AcceleoColor color) {
	IPreferencesService service = Platform.getPreferencesService();
	String defaultValue = StringConverter.asString(color.getDefault());

	String value = service.get(color.getPreferenceKey(), defaultValue, getPreferenceLookupOrder());
	RGB rgbValue = StringConverter.asRGB(value);

	return rgbValue;
	}

	/**
	* Returns the order in which preferences should be looked up.
	*
	* @return The order in which preferences should be looked up.
	*/
	private IEclipsePreferences[] getPreferenceLookupOrder() {
	return new IEclipsePreferences[] {proxyScope, instanceScope, defaultScope, };
	}

	/**
	* Creates the preview editor.
	*
	* @param parent
	* Parent composite of this editor.
	* @return The preview editor.
	*/
	private Control createPreviewViewer(Composite parent) {
	final SourceViewer previewViewer = new SourceViewer(parent, null, null, false, SWT.BORDER
	\| SWT.V_SCROLL \| SWT.H_SCROLL);
	final AcceleoConfiguration configuration = new AcceleoConfiguration(AcceleoUIActivator.getDefault()
	.getPreferenceStore(), getPreferenceLookupOrder());

	IDocument document = new Document();
	previewViewer.setDocument(document);

	previewViewer.configure(configuration);
	previewViewer.setEditable(false);

	String previewContent = AcceleoColorMessages.getString("editor.preview"); //$NON-NLS-1$
	document.set(previewContent);

	// Setup syntax highlighting and partitioning
	IDocumentPartitioner partitioner = new FastPartitioner(new AcceleoPartitionScanner(),
	AcceleoPartitionScanner.LEGAL_CONTENT_TYPES);
	partitioner.connect(document);
	document.setDocumentPartitioner(partitioner);

	final IPreferenceChangeListener preferenceListener = new IPreferenceChangeListener() {
	/**
	* {@inheritDoc}
	*
	* @see org.eclipse.core.runtime.preferences.IEclipsePreferences.IPreferenceChangeListener#preferenceChange(org.eclipse.core.runtime.preferences.IEclipsePreferences.PreferenceChangeEvent)
	*/
	public void preferenceChange(PreferenceChangeEvent event) {
	configuration.adaptToPreferenceChanges(event);
	previewViewer.invalidateTextPresentation();
	}
	};

	proxyScope.addPreferenceChangeListener(preferenceListener);
	previewViewer.getTextWidget().addDisposeListener(new DisposeListener() {
	public void widgetDisposed(DisposeEvent e) {
	proxyScope.removePreferenceChangeListener(preferenceListener);
	}
	});

	return previewViewer.getControl();
	}

	/**
	* Label provider for our {@link #colorViewer}.
	*
	* @author <a href="mailto:laurent.goubet@obeo.fr">Laurent Goubet</a>
	*/
	private class ColorViewerLabelProvider extends LabelProvider implements IColorProvider {
	/**
	* {@inheritDoc}
	*
	* @see org.eclipse.jface.viewers.IColorProvider#getBackground(java.lang.Object)
	*/
	public Color getBackground(Object element) {
	return null;
	}

	/**
	* {@inheritDoc}
	*
	* @see org.eclipse.jface.viewers.IColorProvider#getForeground(java.lang.Object)
	*/
	public Color getForeground(Object element) {
	return null;
	}

	/**
	* {@inheritDoc}
	*
	* @see org.eclipse.jface.viewers.LabelProvider#getText(java.lang.Object)
	*/
	@Override
	public String getText(Object element) {
	if (element instanceof ColorCategory) {
	return ((ColorCategory)element).getName();
	}
	return ((ColorItem)element).getName();
	}
	}

	/**
	* Content provider for our {@link #colorViewer}.
	*
	* @author <a href="mailto:laurent.goubet@obeo.fr">Laurent Goubet</a>
	*/
	private class ColorViewerContentProvider implements ITreeContentProvider {
	/**
	* {@inheritDoc}
	*
	* @see org.eclipse.jface.viewers.ITreeContentProvider#getElements(java.lang.Object)
	*/
	@SuppressWarnings("unchecked")
	public Object[] getElements(Object inputElement) {
	if (inputElement instanceof List) {
	List<ColorCategory> input = (List<ColorCategory>)inputElement;
	return input.toArray(new ColorCategory[input.size()]);
	}
	return null;
	}

	/**
	* {@inheritDoc}
	*
	* @see org.eclipse.jface.viewers.ITreeContentProvider#getChildren(java.lang.Object)
	*/
	public Object[] getChildren(Object parentElement) {
	if (parentElement instanceof ColorCategory) {
	return ((ColorCategory)parentElement).getChildren();
	}
	return null;
	}

	/**
	* {@inheritDoc}
	*
	* @see org.eclipse.jface.viewers.ITreeContentProvider#getParent(java.lang.Object)
	*/
	public Object getParent(Object element) {
	if (element instanceof ColorItem) {
	return ((ColorItem)element).getCategory();
	}
	return null;
	}

	/**
	* {@inheritDoc}
	*
	* @see org.eclipse.jface.viewers.ITreeContentProvider#hasChildren(java.lang.Object)
	*/
	public boolean hasChildren(Object element) {
	return element instanceof ColorCategory;
	}

	/**
	* {@inheritDoc}
	*
	* @see org.eclipse.jface.viewers.IContentProvider#inputChanged(org.eclipse.jface.viewers.Viewer,
	* java.lang.Object, java.lang.Object)
	*/
	public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
	// We do not need to react to input changes
	}

	/**
	* {@inheritDoc}
	*
	* @see org.eclipse.jface.viewers.IContentProvider#dispose()
	*/
	public void dispose() {
	// Nothing to dispose
	}
	}

	/**
	* Represents a category in the color viewer.
	*
	* @author <a href="mailto:laurent.goubet@obeo.fr">Laurent Goubet</a>
	*/
	private class ColorCategory {
	/** List of this category's children. */
	private final ColorItem[] children;

	/** Human-readable name of this category. */
	private final String displayName;

	/**
	* Instantiates a Category given its children colors.
	*
	* @param displayName
	* Display name of this category.
	* @param children
	* The colors that are to be displayed as children of this category.
	*/
	public ColorCategory(String displayName, AcceleoColor[] children) {
	this.displayName = displayName;
	this.children = new ColorItem[children.length];
	for (int i = 0; i < children.length; i++) {
	this.children[i] = new ColorItem(this, children[i]);
	}
	}

	/**
	* Returns the name of this category.
	*
	* @return The name of this category.
	*/
	public String getName() {
	return displayName;
	}

	/**
	* Returns the children of this category.
	*
	* @return The children of this category.
	*/
	public ColorItem[] getChildren() {
	return children;
	}
	}

	/**
	* Wraps an {@link AcceleoColor} for our tree viewer.
	*
	* @author <a href="mailto:laurent.goubet@obeo.fr">Laurent Goubet</a>
	*/
	private class ColorItem {
	/** Category in which this item is displayed. */
	private final ColorCategory category;

	/** The wrapped color. */
	private final AcceleoColor color;

	/**
	* Instantiates a tree item given its wrapped color.
	*
	* @param category
	* The category this color belongs to.
	* @param color
	* The color we are to wrap.
	*/
	public ColorItem(ColorCategory category, AcceleoColor color) {
	this.category = category;
	this.color = color;
	}

	/**
	* Returns the wrapped {@link AcceleoColor}.
	*
	* @return The wrapped {@link AcceleoColor}.
	*/
	public AcceleoColor getColor() {
	return color;
	}

	/**
	* Returns the human-readable name for the wrapped color.
	*
	* @return The human-readable name for the wrapped color.
	*/
	public String getName() {
	return AcceleoColorMessages.getString(color.getPreferenceKey());
	}

	/**
	* Returns the category in which this item is displayed.
	*
	* @return The category in which this item is displayed.
	*/
	public ColorCategory getCategory() {
	return category;
	}
	}
	}