com.itextpdf.kernel.xmp.XMPIterator Maven / Gradle / Ivy
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// http://www.adobe.com/devnet/xmp/library/eula-xmp-library-java.html
package com.itextpdf.kernel.xmp;
import java.util.Iterator;
/**
* Interface for the {@code XMPMeta} iteration services.
* {@code XMPIterator} provides a uniform means to iterate over the
* schema and properties within an XMP object.
*
* 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}. This is also described in the XMP
* Specification, in the XMP Data Model chapter.
*
* 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()}). 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.
*
* An {@code XMPIterator} is created by {@code 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.
*
* The {@code XMPIterator#next()} 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.
*
* The options to control the iteration are:
*
* - 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.
*
- JUST_LEAFNODES - Visit just the leaf property nodes and their
* qualifiers.
*
- JUST_LEAFNAME - Return just the leaf component of the node names.
* The default is to return the full xmp path.
*
- OMIT_QUALIFIERS - Do not visit the qualifiers.
*
- INCLUDE_ALIASES - Adds known alias properties to the properties in the iteration.
* Note: Not supported in Java XMPCore!
*
*
* {@code next()} returns {@code XMPPropertyInfo}-objects and throws
* a {@code NoSuchElementException} if there are no more properties to
* return.
*
* @since 25.01.2006
*/
public interface XMPIterator extends Iterator
{
/**
* Skip the subtree below the current node when next() is
* called.
*/
void skipSubtree();
/**
* Skip the subtree below and remaining siblings of the current node when
* next() is called.
*/
void skipSiblings();
}