/*******************************************************************************
 * Copyright (c) 2004, 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.debug.ui.memory;

import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.debug.core.model.IMemoryBlock;
import org.eclipse.jface.util.IPropertyChangeListener;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;

/**
 * An arbitrary rendering of a memory block. A memory rendering is contributed
 * via the <code>memoryRenderings</code> extension point.
 * <p>
 * Following is an example definition of a memory renderings extension.
 * <pre>
 * &lt;extension point="org.eclipse.debug.ui.memoryRenderings"&gt;
 *   &lt;memoryRenderingType
 *      id="com.example.asciiRendering"
 *      name="ASCII"
 *      class="com.example.RenderingFactory"&gt;
 *   &lt;/memoryRenderingType&gt;
 * &lt;/extension&gt;
 * </pre>
 * The attributes are specified as follows:
 * <ul>
 * <li><code>id</code> specifies a unique identifier for a type of memory rendering</li>
 * <li><code>name</code> specifies a human readable label for a rendering type</li>
 * <li><code>class</code> specifies the fully qualified name of the Java class
 *   that implements <code>IMemoryRenderingTypeDelegate</code>. Renderings are created
 *   via this factory.</li>
 * </ul>
 * </p>
 * <p>
 * A rendering provides an image and label. To support dynamic labels and images, property
 * change notification is used with the following property constants defined in
 * <code>IBasicPropertyConstants</code>:
 * <ul>
 * <li><code>P_TEXT</code> - indicates a label change</li>
 * <li><code>P_IMAGE</code> - indicates a image change</li>
 * </ul>
 * </p>
 * <p>
 * Renderings needing to synchronize with other renderings are intended to use
 * property change notifications via its synchronization service. For example, when a
 * rendering becomes visible, it can register for property change events with its rendering
 * site's synchronization service, and when it becomes hidden it can unregister. When a
 * rendering is activated, it should set itself as the synchrnoization provider in its
 * rendering site and fire property change events to communicate information to
 * interested listeners.
 * </p> 
 * <p>
 * Clients contributing a memory rendering type are intended to implement this interface
 * and <code>IMemoryRenderingTypeDelegate</code>. The factory will be used to create instances
 * of <code>IMemoryRendering</code>.
 * </p>
 * @since 3.1
 */
public interface IMemoryRendering extends IAdaptable{
    
    /**
     * Initializes this rendering to be hosted in the given container, displaying
     * the given memory block. This method is called before this rendering's control
     * has been created.
     * 
     * @param container container hosting this rendering
     * @param block the memory block to render
     */
    public void init(IMemoryRenderingContainer container, IMemoryBlock block);
    
    /**
     * Creates the top level control for this rendering under the given parent composite.
     * This method is called after this rendering's <code>init</code> method has been
     * called.
     * <p>
     * Implementors are responsible for ensuring that
     * the created control can be accessed via <code>getControl</code>
     * </p>
     * @param parent the parent composite
     */
    public Control createControl(Composite parent);

    /**
     * Returns the top level control for this rendering.
     * <p>
     * May return <code>null</code> if the control
     * has not been created yet.
     * </p>
     * @return the top level control or <code>null</code>
     */
    public Control getControl();
    
    /**
     * Disposes this rendering.
     */
    public void dispose();
    
    /**
     * Notification this rendering has become the active rendering. Only one
     * rendering can be active at once. Generally, the active rendering is
     * visible and has focus.
     */
    public void activated();
    
    /**
     * Notification this rendering is no longer the active rendering.
     */
    public void deactivated();
    
    /**
     * Notification this rendering has become visible in its container.
     * Note that a rendering does not have to be active to be visible.
     */
    public void becomesVisible();
    
    /**
     * Notification this rendering has become hidden in its container.
     */
    public void becomesHidden();
    
    /**
     * Returns the memory block displayed by this rendering.
     * 
     * @return the memory block displayed by this rendering
     */
    public IMemoryBlock getMemoryBlock();
    
    /**
     * Returns the identifier associated with this rendering's type.
     *  
     * @return the identifier associated with this rendering's type
     * @see IMemoryRenderingType
     */
    public String getRenderingId();
    
    /**
     * Adds a listener for property changes to this rendering.
     * Has no effect if an identical listener is already registered.
     * 
     * @param listener a property change listener
     */
    public void addPropertyChangeListener(IPropertyChangeListener listener);
    
    /**
     * Removes the given property change listener from this rendering.
     * Has no effect if the identical listener is not registered.
     *
     * @param listener a property change listener
     */
    public void removePropertyChangeListener(IPropertyChangeListener listener);
    
    /**
     * Returns an image for this rendering. Clients should not dispose
     * this image. This rendering will dispose the image if required when
     * this rendering is disposed.
     * 
     * @return an image for this rendering
     */
    public Image getImage();
    
    /**
     * Returns a label for this rendering.
     * 
     * @return a label for this rendering
     */
    public String getLabel();
}