/*******************************************************************************
 * Copyright (c) 2000, 2006 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.ui.dialogs;

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

import org.eclipse.jface.viewers.ITableLabelProvider;
import org.eclipse.jface.viewers.LabelProvider;
import org.eclipse.osgi.util.TextProcessor;
import org.eclipse.swt.graphics.Image;
import org.eclipse.ui.IFileEditorMapping;

/**
 * A label provider for displaying of <code>IFileEditorMapping
 * objects in viewers.
 * <p>
 * This class has a singleton instance, 
 * <code>FileEditorMappingLabelProvider.INSTANCE,
 * which can be used any place this kind of label provider is needed.
 * </p>
 * <p>
 * The singleton instance hangs on to images, which get freed up when 
 * <code>dispose is called.
 * </p>
 *
 * @see org.eclipse.jface.viewers.ILabelProvider
 */
public class FileEditorMappingLabelProvider extends LabelProvider implements
        ITableLabelProvider {

    /**
     * Singleton instance accessor.
     */
    public final static FileEditorMappingLabelProvider INSTANCE = new FileEditorMappingLabelProvider();

    /**
     * Images that will require disposal.
     */
    private List imagesToDispose = new ArrayList();

    /**
     * Creates an instance of this class.  The private visibility of this
     * constructor ensures that this class is only usable as a singleton.
     */
    private FileEditorMappingLabelProvider() {
        super();
    }

    /* (non-Javadoc)
     * Method declared on ILabelProvider.
     */
    public void dispose() {
        super.dispose();
        for (Iterator e = imagesToDispose.iterator(); e.hasNext();) {
            ((Image) e.next()).dispose();
        }
        imagesToDispose.clear();
    }

    /**
     * The <code>ResourceTypeEditorMappingLabelProvider implementation of this
     * <code>ITableLabelProvider method creates and returns an new image. The 
     * image is remembered internally and will be deallocated by
     * <code>dispose.
     */
    public Image getColumnImage(Object element, int row) {
        return getImage(element);
    }

    /* (non-Javadoc)
     * Method declared on ITableLabelProvider.
     */
    public String getColumnText(Object element, int row) {
        return getText(element);
    }

    /**
     * The <code>ResourceTypeEditorMappingLabelProvider implementation of this
     * <code>ILabelProvider method creates and returns an new image. The image
     * is remembered internally and will be deallocated by <code>dispose.
     */
    public Image getImage(Object element) {
        if (element instanceof IFileEditorMapping) {
            Image image = ((IFileEditorMapping) element).getImageDescriptor()
                    .createImage();
            imagesToDispose.add(image);
            return image;
        }
        return null;
    }

    /* (non-Javadoc)
     * Method declared on ILabelProvider.
     */
    public String getText(Object element) {
        if (element instanceof IFileEditorMapping) {
			return TextProcessor.process(((IFileEditorMapping) element)
					.getLabel(), "*."); //$NON-NLS-1$
		}

		return null;
    }
}