/*******************************************************************************
 * 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.dialogs;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.jface.dialogs.ErrorDialog;
import org.eclipse.jface.preference.PreferenceNode;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.IPluginContribution;
import org.eclipse.ui.IWorkbenchPropertyPage;
import org.eclipse.ui.internal.WorkbenchMessages;

/**
 * Property page node allows us to achive presence in the property page dialog
 * without loading the page itself, thus loading the contributing plugin.
 * Only when the user selects the page will it be loaded.
 */
public class PropertyPageNode extends PreferenceNode implements IPluginContribution {
    private RegistryPageContributor contributor;
    private IWorkbenchPropertyPage page;
    private Image icon;
    private IAdaptable element;
    
    /**
	 * PropertyPageNode constructor.
	 */
    public PropertyPageNode(RegistryPageContributor contributor, IAdaptable element) {
        super(contributor.getPageId());
        this.contributor = contributor;
        this.element = element;
    }
    
    /**
	 * Creates the preference page this node stands for. If the page is null,
     * it will be created by loading the class. If loading fails,
     * empty filler page will be created instead.
	 */
    public void createPage() {
        try {
            page = contributor.createPage(element);
	} catch (CoreException e) {
            // Just inform the user about the error. The details are
            // written to the log by now.
		ErrorDialog.openError(
			(Shell)null, 
			WorkbenchMessages.getString("PropertyPageNode.errorTitle"),  //$NON-NLS-1$
            WorkbenchMessages.getString("PropertyPageNode.errorMessage"), //$NON-NLS-1$
            e.getStatus());
            page = new EmptyPropertyPage();
        }
        setPage(page);
    }
   /** (non-Javadoc)
     * Method declared on IPreferenceNode.
	 */
    public void disposeResources() {

        if (page != null) {
            page.dispose();
            page = null;
        }
        if (icon != null) {
            icon.dispose();
            icon = null;
        }
    }
    
    /**
	 * Returns page icon, if defined.
	 */
    public Image getLabelImage() {
        if (icon == null) {
            ImageDescriptor desc = contributor.getPageIcon();
            if (desc != null) {
                icon = desc.createImage();
            }
        }
        return icon;
    }
    
    /**
	 * Returns page label as defined in the registry.
	 */
    public String getLabelText() {
        return contributor.getPageName();
    }

	/* (non-Javadoc)
	 * @see org.eclipse.ui.activities.support.IPluginContribution#fromPlugin()
	 */
	public boolean fromPlugin() {
		return true;
	}

	/* (non-Javadoc)
	 * @see org.eclipse.ui.activities.support.IPluginContribution#getLocalId()
	 */
	public String getLocalId() {
		return getId();
	}

	/* (non-Javadoc)
	 * @see org.eclipse.ui.activities.support.IPluginContribution#getPluginId()
	 */
	public String getPluginId() {
		return contributor.getPluginId();
	}
}