/*
 * @(#)IIOMetadata.java	1.41 05/11/17
 *
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package javax.imageio.metadata;

import org.w3c.dom.Node;
import java.lang.reflect.Method;

/**
 * An abstract class to be extended by objects that represent metadata
 * (non-image data) associated with images and streams.  Plug-ins
 * represent metadata using opaque, plug-in specific objects.  These
 * objects, however, provide the ability to access their internal
 * information as a tree of <code>IIOMetadataNode</code> objects that
 * support the XML DOM interfaces as well as additional interfaces for
 * storing non-textual data and retrieving information about legal
 * data values.  The format of such trees is plug-in dependent, but
 * plug-ins may choose to support a plug-in neutral format described
 * below.  A single plug-in may support multiple metadata formats,
 * whose names maybe determined by calling
 * <code>getMetadataFormatNames</code>.  The plug-in may also support
 * a single special format, referred to as the "native" format, which
 * is designed to encode its metadata losslessly.  This format will
 * typically be designed specifically to work with a specific file
 * format, so that images may be loaded and saved in the same format
 * with no loss of metadata, but may be less useful for transfering
 * metadata between an <code>ImageReader</code> and an
 * <code>ImageWriter</code> for different image formats.  To convert
 * between two native formats as losslessly as the image file formats
 * will allow, an <code>ImageTranscoder</code> object must be used.
 *
 * @see javax.imageio.ImageReader#getImageMetadata
 * @see javax.imageio.ImageReader#getStreamMetadata
 * @see javax.imageio.ImageReader#readAll
 * @see javax.imageio.ImageWriter#getDefaultStreamMetadata
 * @see javax.imageio.ImageWriter#getDefaultImageMetadata
 * @see javax.imageio.ImageWriter#write
 * @see javax.imageio.ImageWriter#convertImageMetadata
 * @see javax.imageio.ImageWriter#convertStreamMetadata
 * @see javax.imageio.IIOImage
 * @see javax.imageio.ImageTranscoder
 *
 * @version 0.5
 */
public abstract class IIOMetadata {

    /**
     * A boolean indicating whether the concrete subclass supports the
     * standard metadata format, set via the constructor.
     */
    protected boolean standardFormatSupported;

    /**
     * The name of the native metadata format for this object,
     * initialized to <code>null</code> and set via the constructor.
     */
    protected String nativeMetadataFormatName = null;

    /**
     * The name of the class implementing <code>IIOMetadataFormat</code>
     * and representing the native metadata format, initialized to
     * <code>null</code> and set via the constructor.
     */
    protected String nativeMetadataFormatClassName = null;
    
    /**
     * An array of names of formats, other than the standard and
     * native formats, that are supported by this plug-in,
     * initialized to <code>null</code> and set via the constructor.
     */
    protected String[] extraMetadataFormatNames = null;

    /**
     * An array of names of classes implementing <code>IIOMetadataFormat</code>
     * and representing the metadata formats, other than the standard and
     * native formats, that are supported by this plug-in,
     * initialized to <code>null</code> and set via the constructor.
     */
    protected String[] extraMetadataFormatClassNames = null;

    /**
     * An <code>IIOMetadataController</code> that is suggested for use
     * as the controller for this <code>IIOMetadata</code> object.  It
     * may be retrieved via <code>getDefaultController</code>.  To
     * install the default controller, call
     * <code>setController(getDefaultController())</code>.  This
     * instance variable should be set by subclasses that choose to
     * provide their own default controller, usually a GUI, for
     * setting parameters.
     *
     * @see IIOMetadataController
     * @see #getDefaultController
     */
    protected IIOMetadataController defaultController = null;

    /**