content: // =================================================================================================
  // ADOBE SYSTEMS INCORPORATED
  // Copyright 2006 Adobe Systems Incorporated
  // All Rights Reserved
  //
  // NOTICE:  Adobe permits you to use, modify, and distribute this file in accordance with the terms
  // of the Adobe license agreement accompanying it.
  // =================================================================================================
  
  package com.adobe.internal.xmp;
  
  import java.util.Iterator;
  
  
  /**
   * Interface for the <code>XMPMeta</code> iteration services.
   * <code>XMPIterator</code> provides a uniform means to iterate over the
   * schema and properties within an XMP object.
   * <p>
   * The iteration over the schema and properties within an XMP object is very
   * complex. It is helpful to have a thorough understanding of the XMP data tree.
   * One way to learn this is to create some complex XMP and examine the output of
   * <code>XMPMeta#toString</code>. This is also described in the XMP
   * Specification, in the XMP Data Model chapter.
   * <p>
   * The top of the XMP data tree is a single root node. This does not explicitly
   * appear in the dump and is never visited by an iterator (that is, it is never
   * returned from <code>XMPIterator#next()</code>). Beneath the root are
   * schema nodes. These are just collectors for top level properties in the same
   * namespace. They are created and destroyed implicitly. Beneath the schema
   * nodes are the property nodes. The nodes below a property node depend on its
   * type (simple, struct, or array) and whether it has qualifiers.
   * <p>
   * An <code>XMPIterator</code> is created by XMPMeta#interator() constructor
   * defines a starting point for the iteration and options that control how it
   * proceeds. By default the iteration starts at the root and visits all nodes
   * beneath it in a depth first manner. The root node is not visited, the first
   * visited node is a schema node. You can provide a schema name or property path
   * to select a different starting node. By default this visits the named root
   * node first then all nodes beneath it in a depth first manner.
   * <p>
   * The <code>XMPIterator#next()</code> method delivers the schema URI, path,
   * and option flags for the node being visited. If the node is simple it also
   * delivers the value. Qualifiers for this node are visited next. The fields of
   * a struct or items of an array are visited after the qualifiers of the parent.
   * <p>
   * The options to control the iteration are:
   * <ul>
   * <li>JUST_CHILDREN - Visit just the immediate children of the root. Skip
   * the root itself and all nodes below the immediate children. This omits the
   * qualifiers of the immediate children, the qualifier nodes being below what
   * they qualify, default is to visit the complete subtree.
   * <li>JUST_LEAFNODES - Visit just the leaf property nodes and their
   * qualifiers.
   * <li>JUST_LEAFNAME - Return just the leaf component of the node names.
   * The default is to return the full xmp path.
   * <li>OMIT_QUALIFIERS - Do not visit the qualifiers.
   * <li>INCLUDE_ALIASES - Adds known alias properties to the properties in the iteration.
   * 		<em>Note:</em> Not supported in Java XMPCore!
   * </ul>
   * <p>
   * <code>next()</code> returns <code>XMPPropertyInfo</code>-objects and throws
   * a <code>NoSuchElementException</code> if there are no more properties to
   * return.
   *
   * @author Stefan Makswit
   * @version $Revision$
   * @since 25.01.2006
   */
  public interface XMPIterator extends Iterator
  {
  	/**
  	 * Skip the subtree below the current node when <code>next()</code> is
  	 * called.
  	 */
  	void skipSubtree();
  
  
  	/**
  	 * Skip the subtree below and remaining siblings of the current node when
  	 * <code>next()</code> is called.
  	 */
  	void skipSiblings();
  }