xmpnodeutils.java

flash xmp sdk,flash官方SDK

// =================================================================================================
// ADOBE SYSTEMS INCORPORATED
// Copyright 2006-2007 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.xmp.impl;

import java.util.Calendar;
import java.util.Iterator;

import com.adobe.xmp.XMPConst;
import com.adobe.xmp.XMPDateTime;
import com.adobe.xmp.XMPDateTimeFactory;
import com.adobe.xmp.XMPError;
import com.adobe.xmp.XMPException;
import com.adobe.xmp.XMPMetaFactory;
import com.adobe.xmp.XMPUtils;
import com.adobe.xmp.impl.xpath.XMPPath;
import com.adobe.xmp.impl.xpath.XMPPathSegment;
import com.adobe.xmp.options.AliasOptions;
import com.adobe.xmp.options.PropertyOptions;


/**
 * Utilities for <code>XMPNode</code>.
 * 
 * @since   Aug 28, 2006
 */
public class XMPNodeUtils implements XMPConst
{
	/** */
	static final int CLT_NO_VALUES = 0;
	/** */
	static final int CLT_SPECIFIC_MATCH = 1;
	/** */
	static final int CLT_SINGLE_GENERIC = 2;
	/** */
	static final int CLT_MULTIPLE_GENERIC = 3;
	/** */
	static final int CLT_XDEFAULT = 4;
	/** */
	static final int CLT_FIRST_ITEM = 5;


	/**
	 * Private Constructor
	 */
	private XMPNodeUtils()
	{
		// EMPTY
	}

	
	/**
	 * Find or create a schema node if <code>createNodes</code> is false and
	 *  
	 * @param tree the root of the xmp tree. 
	 * @param namespaceURI a namespace
	 * @param createNodes a flag indicating if the node shall be created if not found.
	 * 		  <em>Note:</em> The namespace must be registered prior to this call.
	 * 
	 * @return Returns the schema node if found, <code>null</code> otherwise.
	 * 		   Note: If <code>createNodes</code> is <code>true</code>, it is <b>always</b>
	 * 		   returned a valid node. 
	 * @throws XMPException An exception is only thrown if an error occurred, not if a
	 *         		node was not found.
	 */
	static XMPNode findSchemaNode(XMPNode tree, String namespaceURI,
			boolean createNodes)
			throws XMPException
	{
		return findSchemaNode(tree, namespaceURI, null, createNodes);
	}
	
	
	/**
	 * Find or create a schema node if <code>createNodes</code> is true.
	 *  
	 * @param tree the root of the xmp tree. 
	 * @param namespaceURI a namespace
	 * @param suggestedPrefix If a prefix is suggested, the namespace is allowed to be registered.
	 * @param createNodes a flag indicating if the node shall be created if not found.
	 * 		  <em>Note:</em> The namespace must be registered prior to this call.
	 * 
	 * @return Returns the schema node if found, <code>null</code> otherwise.
	 * 		   Note: If <code>createNodes</code> is <code>true</code>, it is <b>always</b>
	 * 		   returned a valid node. 
	 * @throws XMPException An exception is only thrown if an error occurred, not if a
	 *         		node was not found.
	 */
	static XMPNode findSchemaNode(XMPNode tree, String namespaceURI, String suggestedPrefix,
			boolean createNodes)
			throws XMPException
	{
		assert tree.getParent() == null; // make sure that its the root
		XMPNode schemaNode = tree.findChildByName(namespaceURI);
		
		if (schemaNode == null  &&  createNodes)
		{
			schemaNode = new XMPNode(namespaceURI, 
				new PropertyOptions()
					.setSchemaNode(true));
			schemaNode.setImplicit(true);
			
			// only previously registered schema namespaces are allowed in the XMP tree.
			String prefix = XMPMetaFactory.getSchemaRegistry().getNamespacePrefix(namespaceURI);
			if (prefix == null)
			{	
				if (suggestedPrefix != null  &&  suggestedPrefix.length() != 0)
				{
					prefix = XMPMetaFactory.getSchemaRegistry().registerNamespace(namespaceURI,
							suggestedPrefix);
				}
				else
				{
					throw new XMPException("Unregistered schema namespace URI",
							XMPError.BADSCHEMA);
				}	
			}	
				
			schemaNode.setValue(prefix);
	
			tree.addChild(schemaNode);
		}
		
		return schemaNode;
	}

	
	/**
	 * Find or create a child node under a given parent node. If the parent node is no 
	 * Returns the found or created child node.
	 * 
	 * @param parent
	 *            the parent node
	 * @param childName
	 *            the node name to find
	 * @param createNodes
	 *            flag, if new nodes shall be created.
	 * @return Returns the found or created node or <code>null</code>.
	 * @throws XMPException Thrown if 
	 */
	static XMPNode findChildNode(XMPNode parent, String childName, boolean createNodes)
			throws XMPException
	{
		if (!parent.getOptions().isSchemaNode() && !parent.getOptions().isStruct())
		{
			if (!parent.isImplicit())
			{
				throw new XMPException("Named children only allowed for schemas and structs",
						XMPError.BADXPATH);
			}	
			else if (parent.getOptions().isArray())
			{
				throw new XMPException("Named children not allowed for arrays",
						XMPError.BADXPATH);
			}
			else if (createNodes)
			{	
				parent.getOptions().setStruct(true);
			}	
		}
			
		XMPNode childNode = parent.findChildByName(childName); 
		
		if (childNode == null  &&  createNodes)
		{
			PropertyOptions options = new PropertyOptions();
			childNode = new XMPNode(childName, options);
			childNode.setImplicit(true);
			parent.addChild(childNode);
		}
		
		assert childNode != null ||  !createNodes;
	
		return childNode;
	}


	/**
	 * Follow an expanded path expression to find or create a node.
	 * 
	 * @param xmpTree the node to begin the search. 
	 * @param xpath the complete xpath
	 * @param createNodes flag if nodes shall be created 
	 * 			(when called by <code>setProperty()</code>)
	 * @param leafOptions the options for the created leaf nodes (only when
	 *			<code>createNodes == true</code>).
	 * @return Returns the node if found or created or <code>null</code>.
	 * @throws XMPException An exception is only thrown if an error occurred, 
	 * 			not if a node was not found.
	 */
	static XMPNode findNode(XMPNode xmpTree, XMPPath xpath, boolean createNodes,
		PropertyOptions leafOptions) throws XMPException
	{
		// check if xpath is set.
		if (xpath == null  ||  xpath.size() == 0)
		{
			throw new XMPException("Empty XMPPath", XMPError.BADXPATH);
		}

		// Root of implicitly created subtree to possible delete it later. 
		// Valid only if leaf is new.
		XMPNode rootImplicitNode = null; 
		XMPNode currNode = null;
		
		// resolve schema step
		currNode = findSchemaNode(xmpTree,
			xpath.getSegment(XMPPath.STEP_SCHEMA).getName(), createNodes);
		if (currNode == null) 
		{
			return null;
		}
		else if (currNode.isImplicit())
		{
			currNode.setImplicit(false);	// Clear the implicit node bit.
			rootImplicitNode = currNode;	// Save the top most implicit node.
		}


		// Now follow the remaining steps of the original XMPPath.
		try
		{
			for (int i = 1; i < xpath.size(); i++)
			{
				currNode = followXPathStep(currNode, xpath.getSegment(i), createNodes);
				if (currNode == null) 
				{
					if (createNodes)
					{	
						// delete implicitly created nodes
						deleteNode(rootImplicitNode);
					}	
					return null;
				}
				else if (currNode.isImplicit())
				{
					// clear the implicit node flag
					currNode.setImplicit(false);

					// if node is an ALIAS (can be only in root step, auto-create array 
					// when the path has been resolved from a not simple alias type
					if (i == 1  &&  
						xpath.getSegment(i).isAlias()  &&
						xpath.getSegment(i).getAliasForm() != 0)
					{
						currNode.getOptions().setOption(xpath.getSegment(i).getAliasForm(), true);
					}
					// "CheckImplicitStruct" in C++
					else if (i < xpath.size() - 1  &&
						xpath.getSegment(i).getKind() == XMPPath.STRUCT_FIELD_STEP  &&	
						!currNode.getOptions().isCompositeProperty())
					{
						currNode.getOptions().setStruct(true);
					}					
					
					if (rootImplicitNode == null)
					{
						rootImplicitNode = currNode;	// Save the top most implicit node.
					}
				}
			}
		}
		catch (XMPException e)
		{
			// if new notes have been created prior to the error, delete them
			if (rootImplicitNode != null)
			{
				deleteNode(rootImplicitNode);
			}
			throw e;
		}
		
		
		if (rootImplicitNode != null)
		{
			// set options only if a node has been successful created
			currNode.getOptions().mergeWith(leafOptions);
			currNode.setOptions(currNode.getOptions());
		}
		
		return currNode;
	}


	/**
	 * Deletes the the given node and its children from its parent.
	 * Takes care about adjusting the flags.
	 * @param node the top-most node to delete.
	 */
	static void deleteNode(XMPNode node)
	{
		XMPNode parent = node.getParent();
		
		if (node.getOptions().isQualifier())
		{
			// root is qualifier
			parent.removeQualifier(node);
		}
		else
		{
			// root is NO qualifier
			parent.removeChild(node);
		}
		
		// delete empty Schema nodes
		if (!parent.hasChildren()  &&  parent.getOptions().isSchemaNode())
		{
			parent.getParent().removeChild(parent);
		}
	}


	/**
	 * This is setting the value of a leaf node.
	 * 
	 * @param node an XMPNode
	 * @param value a value
	 */
	static void setNodeValue(XMPNode node, Object value)
	{
		String strValue = serializeNodeValue(value);
		if (!(node.getOptions().isQualifier()  &&  XML_LANG.equals(node.getName()))) 
		{	
			node.setValue(strValue);
		}
		else
		{
			node.setValue(Utils.normalizeLangValue(strValue));
		}
	}
	
	
	/**
	 * Verifies the PropertyOptions for consistancy and updates them as needed. 
	 * If options are <code>null</code> they are created with default values.
	 *  
	 * @param options the <code>PropertyOptions</code>
	 * @param itemValue the node value to set
	 * @return Returns the updated options.
	 * @throws XMPException If the options are not consistant. 
	 */
	static PropertyOptions verifySetOptions(PropertyOptions options, Object itemValue)
			throws XMPException
	{
		// create empty and fix existing options
		if (options == null)
		{
			// set default options
			options = new PropertyOptions();
		}
		
		if (options.isArrayAltText())
		{
			options.setArrayAlternate(true);
		}
	
		if (options.isArrayAlternate())
		{
			options.setArrayOrdered(true);
		}
	
		if (options.isArrayOrdered())
		{
			options.setArray(true);
		}
	
		if (options.isCompositeProperty() && itemValue != null && itemValue.toString().length() > 0)
		{
			throw new XMPException("Structs and arrays can't have values",
				XMPError.BADOPTIONS);
		}
	
		options.assertConsistency(options.getOptions());
		
		return options;
	}


	/**
	 * Converts the node value to String, apply special conversions for defined
	 * types in XMP.
	 * 
	 * @param value
	 *            the node value to set
	 * @return Returns the String representation of the node value.
	 */
	static String serializeNodeValue(Object value)
	{
		String strValue;
		if (value == null)
		{
			strValue = null;
		}
		else if (value instanceof Boolean)
		{
			strValue = XMPUtils.convertFromBoolean(((Boolean) value).booleanValue());
		}
		else if (value instanceof Integer)
		{
			strValue = XMPUtils.convertFromInteger(((Integer) value).intValue());
		}
		else if (value instanceof Long)
		{
			strValue = XMPUtils.convertFromLong(((Long) value).longValue());
		}
		else if (value instanceof Double)
		{
			strValue = XMPUtils.convertFromDouble(((Double) value).doubleValue());
		}
		else if (value instanceof XMPDateTime)
		{
			strValue = XMPUtils.convertFromDate((XMPDateTime) value);
		}
		else if (value instanceof Calendar)
		{
			XMPDateTime dt = XMPDateTimeFactory.createFromCalendar((Calendar) value);
			strValue = XMPUtils.convertFromDate(dt);
		}
		else if (value instanceof byte[])
		{
			strValue = XMPUtils.encodeBase64((byte[]) value);
		}
		else
		{
			strValue = value.toString();
		}
	
		return strValue != null ? Utils.removeControlChars(strValue) : null;
	}
	
	
	/** 
	 * After processing by ExpandXPath, a step can be of these forms:
	 * <ul>
	 * 	<li>qualName - A top level property or struct field.
	 * <li>[index] - An element of an array.
	 * <li>[last()] - The last element of an array.
	 * <li>[qualName="value"] - An element in an array of structs, chosen by a field value.
	 * <li>[?qualName="value"] - An element in an array, chosen by a qualifier value.
	 * <li>?qualName - A general qualifier.
	 * </ul>
	 * Find the appropriate child node, resolving aliases, and optionally creating nodes.
	 * 
	 * @param parentNode the node to start to start from 
	 * @param nextStep the xpath segment 
	 * @param createNodes 
	 * @return returns the found or created XMPPath node 
	 * @throws XMPException 
	 */
	private static XMPNode followXPathStep(
				XMPNode parentNode, 
				XMPPathSegment nextStep,
				boolean createNodes) throws XMPException
	{
		XMPNode nextNode = null;
		int index = 0;
		int stepKind = nextStep.getKind();
		
		if (stepKind == XMPPath.STRUCT_FIELD_STEP)
		{
			nextNode = findChildNode(parentNode, nextStep.getName(), createNodes);