/*******************************************************************************
 * Copyright (c) 2000, 2005 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;

import org.eclipse.jface.resource.ImageDescriptor;

/**
 * A perspective descriptor describes a perspective in an
 * <code>IPerspectiveRegistry</code>.  
 * <p>
 * A perspective is a template for view visibility, layout, and action visibility
 * within a workbench page. There are two types of perspective: a predefined 
 * perspective and a custom perspective.  
 * <ul>
 *   <li>A predefined perspective is defined by an extension to the workbench's 
 *     perspective extension point (<code>"org.eclipse.ui.perspectives"</code>).
 *     The extension defines a id, label, and <code>IPerspectiveFactory</code>.
 *     A perspective factory is used to define the initial layout for a page.
 *     </li>
 *   <li>A custom perspective is defined by the user.  In this case a predefined
 *     perspective is modified to suit a particular task and saved as a new
 *     perspective.  The attributes for the perspective are stored in a separate file 
 *     in the workbench's metadata directory.
 *     </li>
 * </ul>
 * </p>
 * <p>
 * Within a page the user can open any of the perspectives known
 * to the workbench's perspective registry, typically by selecting one from the
 * workbench's <code>Open Perspective</code> menu. When selected, the views
 * and actions within the active page rearrange to reflect the perspective.
 * </p>
 * <p>
 * This interface is not intended to be implemented by clients.
 * </p>
 * @see IPerspectiveRegistry
 * @noimplement This interface is not intended to be implemented by clients.
 */
public interface IPerspectiveDescriptor {
    /**
     * Returns the description of this perspective.
     * This is the value of its <code>"description"</code> attribute.
     *
     * @return the description
     * @since 3.0
     */
    public String getDescription();

    /**
     * Returns this perspective's id. For perspectives declared via an extension,
     * this is the value of its <code>"id"</code> attribute.
     *
     * @return the perspective id
     */
    public String getId();

    /**
     * Returns the descriptor of the image to show for this perspective.
     * If the extension for this perspective specifies an image, the descriptor
     * for it is returned.  Otherwise a default image is returned.
     *
     * @return the descriptor of the image to show for this perspective
     */
    public ImageDescriptor getImageDescriptor();

    /**
     * Returns this perspective's label. For perspectives declared via an extension,
     * this is the value of its <code>"label"</code> attribute.
     *
     * @return the label
     */
    public String getLabel();
}