xmpserializerrdf.java

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		{
			XMPNode qualifier = (XMPNode) it.next();
			declareNamespace(qualifier.getName(), null, usedPrefixes, indent);
			declareUsedNamespaces(qualifier, usedPrefixes, indent);
		}
	}
	
	
	/**
	 * Writes one namespace declaration to the output.
	 * @param prefix a namespace prefix (without colon) or a complete qname (when namespace == null)
	 * @param namespace the a namespace
	 * @param usedPrefixes a set containing currently used prefixes
	 * @param indent the current indent level
	 * @throws IOException Forwards all writer exceptions.
	 */
	private void declareNamespace(String prefix, String namespace, Set usedPrefixes, int indent)
			throws IOException
	{
		if (namespace == null)
		{
			// prefix contains qname, extract prefix and lookup namespace with prefix
			QName qname = new QName(prefix);
			if (qname.hasPrefix())
			{
				prefix = qname.getPrefix();
				// add colon for lookup
				namespace = XMPMetaFactory.getSchemaRegistry().getNamespaceURI(prefix + ":");
				// prefix w/o colon
				declareNamespace(prefix, namespace, usedPrefixes, indent);
			}
			else
			{
				return;
			}
		}
		
		if (!usedPrefixes.contains(prefix))
		{
			writeNewline();
			writeIndent(indent);
			write("xmlns:");
			write(prefix);
			write("=\"");
			write(namespace);
			write('"');
			usedPrefixes.add(prefix);
		}
	}


	/**
	 * Recursively handles the "value" for a node. It does not matter if it is a
	 * top level property, a field of a struct, or an item of an array. The
	 * indent is that for the property element. An xml:lang qualifier is written
	 * as an attribute of the property start tag, not by itself forcing the
	 * qualified property form. The patterns below mostly ignore attribute
	 * qualifiers like xml:lang. Except for the one struct case, attribute
	 * qualifiers don't affect the output form.
	 * 
	 * <blockquote>
	 * 
	 * <pre>
	 * 	&lt;ns:UnqualifiedSimpleProperty&gt;value&lt;/ns:UnqualifiedSimpleProperty&gt;
	 * 
	 * 	&lt;ns:UnqualifiedStructProperty rdf:parseType=&quot;Resource&quot;&gt;	
	 * 		(If no rdf:resource qualifier)
	 * 		... Fields, same forms as top level properties
	 * 	&lt;/ns:UnqualifiedStructProperty&gt;
	 * 
	 * 	&lt;ns:ResourceStructProperty rdf:resource=&quot;URI&quot;
	 * 		... Fields as attributes
	 * 	&gt;
	 * 
	 * 	&lt;ns:UnqualifiedArrayProperty&gt;
	 * 		&lt;rdf:Bag&gt; or Seq or Alt
	 * 			... Array items as rdf:li elements, same forms as top level properties
	 * 		&lt;/rdf:Bag&gt;
	 * 	&lt;/ns:UnqualifiedArrayProperty&gt;
	 * 
	 * 	&lt;ns:QualifiedProperty rdf:parseType=&quot;Resource&quot;&gt;
	 * 		&lt;rdf:value&gt; ... Property &quot;value&quot; following the unqualified 
	 * 			forms ... &lt;/rdf:value&gt;
	 * 		... Qualifiers looking like named struct fields
	 * 	&lt;/ns:QualifiedProperty&gt;
	 * </pre>
	 * 
	 * </blockquote>
	 * 
	 * @param node the property node
	 * @param emitAsRDFValue property shall be renderes as attribute rather than tag
	 * @param indent the current indent level
	 * @throws IOException Forwards all writer exceptions.
	 * @throws XMPException If &quot;rdf:resource&quot; and general qualifiers are mixed.
	 */
	private void serializePrettyRDFProperty(XMPNode node, boolean emitAsRDFValue, int indent)
			throws IOException, XMPException
	{
		boolean emitEndTag   = true;
		boolean indentEndTag = true;
	
		// Determine the XML element name. Open the start tag with the name and
		// attribute qualifiers.
		
		String elemName = node.getName();
		if (emitAsRDFValue)
		{
			elemName = "rdf:value";
		}
		else if (XMPConst.ARRAY_ITEM_NAME.equals(elemName))
		{
			elemName = "rdf:li";
		}
	
		writeIndent(indent);
		write('<');
		write(elemName);
		
		boolean isCompact = node.getOptions().isCompact();
		boolean hasGeneralQualifiers = isCompact;	// Might also become true later.
		boolean hasRDFResourceQual   = false;
		
		for (Iterator it = node.iterateQualifier(); it.hasNext();)
		{
			XMPNode qualifier = (XMPNode) it.next();
			if (!RDF_ATTR_QUALIFIER.contains(qualifier.getName()))
			{
				hasGeneralQualifiers = true;
			}
			else
			{
				hasRDFResourceQual = "rdf:resource".equals(qualifier.getName());
				if (!emitAsRDFValue)
				{
					write(' ');
					write(qualifier.getName());
					write("=\"");
					appendNodeValue(qualifier.getValue(), true);
					write('"');
				}
			}
		}
		
		// Process the property according to the standard patterns.
		
		if (hasGeneralQualifiers &&  !emitAsRDFValue)
		{
			// This node has general, non-attribute, qualifiers. Emit using the
			// qualified property form.
			// ! The value is output by a recursive call ON THE SAME NODE with
			// emitAsRDFValue set.
	
			if (hasRDFResourceQual)
			{
				throw new XMPException("Can't mix rdf:resource and general qualifiers",
						XMPError.BADRDF);
			}
			
			write(" rdf:parseType=\"Resource\">");
			writeNewline();
	
			serializePrettyRDFProperty(node, true, indent + 1);
			
			if (isCompact)
			{
				// Emit a "pxmp:compact" fake qualifier.
				writeIndent(indent);
				write("<pxmp:compact/>");
				writeNewline();
			}

			for (Iterator it = node.iterateQualifier(); it.hasNext();)
			{
				XMPNode qualifier = (XMPNode) it.next();
				if (!RDF_ATTR_QUALIFIER.contains(qualifier.getName()))
				{
					serializePrettyRDFProperty(qualifier, false, indent + 1);
				}
			}
		}
		else
		{
			// This node has no general qualifiers. Emit using an unqualified form.
			
			if (!node.getOptions().isCompositeProperty())
			{
				// This is a simple property.
				
				if (node.getOptions().isURI())
				{
					write(" rdf:resource=\"");
					appendNodeValue(node.getValue(), true);
					write("\"/>");
					writeNewline();
					emitEndTag = false;
				}
				else if (node.getValue() == null ||  "".equals(node.getValue()))
				{
					write("/>");
					writeNewline();
					emitEndTag = false;
				} 
				else
				{
					write('>');
					appendNodeValue(node.getValue(), false);
					indentEndTag = false;
				}
			}
			else if (node.getOptions().isArray())
			{
				// This is an array.
				write('>');
				writeNewline();
				emitRDFArrayTag(node, true, indent + 1);
				if (node.getOptions().isArrayAltText())
				{
					XMPNodeUtils.normalizeLangArray(node);
				}
				for (Iterator it = node.iterateChildren(); it.hasNext();)
				{
					XMPNode child = (XMPNode) it.next();
					serializePrettyRDFProperty(child, false, indent + 2);
				}
				emitRDFArrayTag(node, false, indent + 1);
			
			
			} 
			else if (!hasRDFResourceQual)
			{
				// This is a "normal" struct, use the rdf:parseType="Resource" form.
				if (!node.hasChildren())
				{
					write(" rdf:parseType=\"Resource\"/>");
					writeNewline();
					emitEndTag = false;
				}
				else
				{
					write(" rdf:parseType=\"Resource\">");
					writeNewline();
					for (Iterator it = node.iterateChildren(); it.hasNext();)
					{
						XMPNode child = (XMPNode) it.next();
						serializePrettyRDFProperty(child, false, indent + 1);
					}
				}
			}
			else
			{
				// This is a struct with an rdf:resource attribute, use the
				// "empty property element" form.
				for (Iterator it = node.iterateChildren(); it.hasNext();)
				{
					XMPNode child = (XMPNode) it.next();
					if (!canBeRDFAttrProp(child))
					{
						throw new XMPException("Can't mix rdf:resource and complex fields",
								XMPError.BADRDF);
					}
					writeNewline();
					writeIndent(indent + 1);
					write(' ');
					write(child.getName());
					write("=\"");
					appendNodeValue(child.getValue(), true);
					write('"');
				}
				write("/>");
				writeNewline();
				emitEndTag = false;
			}
		}
		
		// Emit the property element end tag.
		if (emitEndTag)
		{
			if (indentEndTag) 
			{
				writeIndent(indent);
			}
			write("</");
			write(elemName);
			write('>');
			writeNewline();
		}		
	}

	
	/**
	 * Writes the array start and end tags.
	 *  
	 * @param arrayNode an array node
	 * @param isStartTag flag if its the start or end tag
	 * @param indent the current indent level
	 * @throws IOException forwards writer exceptions
	 */
	private void emitRDFArrayTag(XMPNode arrayNode, boolean isStartTag, int indent) 
		throws IOException
	{
		if (isStartTag  ||  arrayNode.hasChildren())
		{
			writeIndent(indent);
			write(isStartTag ? "<rdf:" : "</rdf:");
		
			if (arrayNode.getOptions().isArrayAlternate())
			{
				write("Alt");
			} 
			else if (arrayNode.getOptions().isArrayOrdered())
			{
				write("Seq");
			}
			else
			{
				write("Bag");
			}
		
			if (isStartTag && !arrayNode.hasChildren())
			{
				write("/>");
			}
			else
			{
				write(">");
			}
			
			writeNewline();
		}	
	}


	/**
	 * Serializes the node value in XML encoding. Its used for tag bodies and
	 * attributes. <em>Note:</em> The attribute is always limited by quotes,
	 * thats why <code>&amp;apos;</code> is never serialized. <em>Note:</em>
	 * Control chars are written unescaped, but if the user uses others than tab, LF
	 * and CR the resulting XML will become invalid.
	 * 
	 * @param value the value of the node
	 * @param forAttribute flag if value is an attribute value
	 * @throws IOException
	 */
	private void appendNodeValue(String value, boolean forAttribute) throws IOException
	{
		write (Utils.escapeXML(value, forAttribute, true));
	}
	
	
	/**
	 * A node can be serialized as RDF-Attribute, if it meets the following conditions:
	 * <ul>
	 *  	<li>is not array item
	 * 		<li>don't has qualifier
	 * 		<li>is no URI
	 * 		<li>is no composite property
	 * </ul> 
	 * 
	 * @param node an XMPNode
	 * @return Returns true if the node serialized as RDF-Attribute
	 */
	private boolean canBeRDFAttrProp(XMPNode node)
	{
		return
			!node.hasQualifier()  &&
			!node.getOptions().isURI()  &&
			!node.getOptions().isCompositeProperty()  &&
			!XMPConst.ARRAY_ITEM_NAME.equals(node.getName());
	}


	/**
	 * Writes indents and automatically includes the baseindend from the options. 
	 * @param times number of indents to write
	 * @throws IOException forwards exception
	 */
	private void writeIndent(int times) throws IOException
	{
		for (int i = options.getBaseIndent() + times; i > 0; i--)
		{
			writer.write(options.getIndent());
		}
	}
	
	
	/**
	 * Writes a char to the output.
	 * @param c a char
	 * @throws IOException forwards writer exceptions
	 */
	private void write(int c) throws IOException
	{
		writer.write(c);
	}
	
	
	/**
	 * Writes a String to the output.
	 * @param str a String
	 * @throws IOException forwards writer exceptions
	 */
	private void write(String str) throws IOException
	{
		writer.write(str);
	}
	
	
	/**
	 * Writes an amount of chars, mostly spaces
	 * @param number number of chars
	 * @param c a char
	 * @throws IOException
	 */
	private void writeChars(int number, char c) throws IOException
	{
		for (; number > 0; number--)
		{
			writer.write(c);
		}
	}
	
	
	/**
	 * Writes a newline according to the options.
	 * @throws IOException Forwards exception
	 */
	private void writeNewline() throws IOException
	{
		writer.write(options.getNewline());
	}
}