src/main/java/org/apache/struts/annotations/taglib/apt/TagAnnotationProcessor.java - struts-annotations - Git at Google

 /*
  * $Id:  $
  *
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you under the Apache License, Version 2.0 (the
  * "License"); you may not use this file except in compliance
  * with the License.  You may obtain a copy of the License at
  *
  *  http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing,
  * software distributed under the License is distributed on an
  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  * KIND, either express or implied.  See the License for the
  * specific language governing permissions and limitations
  * under the License.
  */
 package org.apache.struts.annotations.taglib.apt;
 import java.io.BufferedWriter;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.FileWriter;
 import java.io.OutputStreamWriter;
 import java.io.PrintWriter;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.Map;

 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.DocumentBuilderFactory;
 import javax.xml.transform.OutputKeys;
 import javax.xml.transform.Result;
 import javax.xml.transform.Source;
 import javax.xml.transform.Transformer;
 import javax.xml.transform.TransformerFactory;
 import javax.xml.transform.dom.DOMSource;
 import javax.xml.transform.stream.StreamResult;

 import org.w3c.dom.Document;
 import org.w3c.dom.Element;
 import org.w3c.dom.Text;

 import com.sun.mirror.apt.AnnotationProcessor;
 import com.sun.mirror.apt.AnnotationProcessorEnvironment;
 import com.sun.mirror.declaration.AnnotationMirror;
 import com.sun.mirror.declaration.AnnotationTypeDeclaration;
 import com.sun.mirror.declaration.AnnotationTypeElementDeclaration;
 import com.sun.mirror.declaration.AnnotationValue;
 import com.sun.mirror.declaration.Declaration;
 import com.sun.mirror.declaration.MethodDeclaration;
 import com.sun.mirror.declaration.TypeDeclaration;

 import freemarker.template.Configuration;
 import freemarker.template.DefaultObjectWrapper;
 import freemarker.template.Template;

 public class TagAnnotationProcessor implements AnnotationProcessor {
   public static final String TAG = "org.apache.struts.annotations.StrutsTag";
   public static final String TAG_ATTRIBUTE = "org.apache.struts.annotations.StrutsTagAttribute";

   private AnnotationProcessorEnvironment environment;
   private AnnotationTypeDeclaration tagDeclaration;
   private AnnotationTypeDeclaration tagAttributeDeclaration;
   private Map<String, Tag> tags = new HashMap<String, Tag>();

   public TagAnnotationProcessor(AnnotationProcessorEnvironment env) {
     environment = env;
     tagDeclaration = (AnnotationTypeDeclaration) environment.getTypeDeclaration(TAG);
     tagAttributeDeclaration = (AnnotationTypeDeclaration) environment
         .getTypeDeclaration(TAG_ATTRIBUTE);
   }

   public void process() {
     //make sure all paramters were set
     checkOptions();

     // tags
     Collection<Declaration> tagDeclarations = environment
         .getDeclarationsAnnotatedWith(tagDeclaration);
     Collection<Declaration> attributesDeclarations = environment
         .getDeclarationsAnnotatedWith(tagAttributeDeclaration);

     // find Tags
     for (Declaration declaration : tagDeclarations) {
       // type
       TypeDeclaration typeDeclaration = (TypeDeclaration) declaration;
       String typeName = typeDeclaration.getQualifiedName();
       HashMap<String, Object> values = getValues(typeDeclaration, tagDeclaration);
       // create Tag and apply values found
       Tag tag = new Tag();
       tag.setDescription((String) values.get("description"));
       tag.setName((String) values.get("name"));
       tag.setTldBodyContent((String) values.get("tldBodyContent"));
       tag.setTldTagClass((String) values.get("tldTagClass"));
       tag.setDeclaredType(typeName);
       // add to map
       tags.put(typeName, tag);
     }

     // find Tags Attributes
     for (Declaration declaration : attributesDeclarations) {
       // type
       MethodDeclaration methodDeclaration = (MethodDeclaration) declaration;
       String typeName = methodDeclaration.getDeclaringType().getQualifiedName();
       HashMap<String, Object> values = getValues(methodDeclaration, tagAttributeDeclaration);
       // create Attribute and apply values found
       TagAttribute attribute = new TagAttribute();
       attribute.setDescription((String) values.get("description"));
       String name = (String) values.get("name");
       if(name == null || name.length() == 0) {
         //get name from method
         String methodName = methodDeclaration.getSimpleName();
         name = String.valueOf(Character.toLowerCase(methodName.charAt(3))) + methodName.substring(4);
       }
       attribute.setName(name);
       attribute.setRequired((Boolean) values.get("required"));
       attribute.setRtexprvalue((Boolean) values.get("rtexprvalue"));
       attribute.setDefaultValue((String) values.get("defaultValue"));
       // add to map
       Tag parentTag = tags.get(typeName);
       if(parentTag != null)
         tags.get(typeName).addTagAttribute(attribute);
       else {
         //an abstract or base class
         parentTag = new Tag();
         parentTag.setDeclaredType(typeName);
         parentTag.setInclude(false);
         parentTag.addTagAttribute(attribute);
         tags.put(typeName, parentTag);
       }
     }

     //we can't process the hierarchy on the first pass because
     //apt does not garantees that the base classes will be processed
     //before their subclasses
     for(Map.Entry<String, Tag> entry : tags.entrySet()) {
       processHierarchy(entry.getValue());
     }

     //save
     saveAsXml();
     saveTemplates();
   }

   private void processHierarchy(Tag tag) {
     try {
       Class clazz = Class.forName(tag.getDeclaredType());
       while((clazz = clazz.getSuperclass()) != null) {
         Tag parentTag = tags.get(clazz.getName());
         //copy parent annotations to this tag
         if(parentTag != null) {
           for(TagAttribute attribute : parentTag.getAttributes()) {
             tag.addTagAttribute(attribute);
           }
         }
       }
     } catch (ClassNotFoundException e) {
       throw new RuntimeException(e);
     }
   }

   private void checkOptions() {
     if(getOption("tlibVersion") == null)
       throw new IllegalArgumentException("'tlibVersion' is missing");
     if(getOption("jspVersion") == null)
       throw new IllegalArgumentException("'jspVersion' is missing");
     if(getOption("shortName") == null)
       throw new IllegalArgumentException("'shortName' is missing");
     if(getOption("description") == null)
       throw new IllegalArgumentException("'description' is missing");
     if(getOption("displayName") == null)
       throw new IllegalArgumentException("'displayName' is missing");
     if(getOption("uri") == null)
       throw new IllegalArgumentException("'uri' is missing");
     if(getOption("outTemplatesDir") == null)
       throw new IllegalArgumentException("'outTemplatesDir' is missing");
     if(getOption("outFile") == null)
 	      throw new IllegalArgumentException("'outFile' is missing");
   }

   private void saveTemplates() {
       //freemarker configuration
       Configuration config = new Configuration();
       config.setClassForTemplateLoading(getClass(), "");
       config.setObjectWrapper(new DefaultObjectWrapper());

       try {
         //load template
         Template template = config.getTemplate("tag.ftl");
         String rootDir = (new File(getOption("outTemplatesDir"))).getAbsolutePath();
         for(Tag tag : tags.values()) {
             if(tag.isInclude()) {
                 //model
                 HashMap root = new HashMap();
                 root.put("tag", tag);

                 //save file
                 BufferedWriter writer = new BufferedWriter(new FileWriter(new File(rootDir, tag.getName() + ".html")));
                 try {
                     template.process(root, writer);
                 } finally {
                     writer.close();
                 }
             }
         }
       } catch (Exception e) {
         //oops we cannot throw checked exceptions
         throw new RuntimeException(e);
       }
   }


   private void saveAsXml() {
     DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
     DocumentBuilder builder;

     try {
       // create xml document
       builder = factory.newDocumentBuilder();
       Document document = builder.newDocument();
       document.setXmlVersion("1.0");

       // taglib
       Element tagLib = document.createElement("taglib");
       document.appendChild(tagLib);
       // tag lib attributes
       appendTextNode(document, tagLib, "tlib-version", getOption("tlibVersion"), false);
       appendTextNode(document, tagLib, "jsp-version", getOption("jspVersion"), false);
       appendTextNode(document, tagLib, "short-name", getOption("shortName"), false);
       appendTextNode(document, tagLib, "uri", getOption("uri"), false);
       appendTextNode(document, tagLib, "display-name", getOption("displayName"), false);
       appendTextNode(document, tagLib, "description", getOption("description"), true);

       // create tags
       for (Map.Entry<String, Tag> entry : tags.entrySet()) {
         Tag tag = entry.getValue();
         if(tag.isInclude())
           createElement(document, tagLib, tag);
       }

       // save to file
       TransformerFactory tf = TransformerFactory.newInstance();
       tf.setAttribute("indent-number", new Integer(2));
       Transformer transformer = tf.newTransformer();
       //if tiger would just format it :(
       //formatting bug in tiger (http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6296446)

       transformer.setOutputProperty(OutputKeys.INDENT, "yes");
       transformer.setOutputProperty(OutputKeys.DOCTYPE_PUBLIC, "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN");
       transformer.setOutputProperty(OutputKeys.DOCTYPE_SYSTEM, "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd");
       transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");

       Source source = new DOMSource(document);
       Result result = new StreamResult(new OutputStreamWriter(new FileOutputStream(getOption("outFile"))));
       transformer.transform(source, result);
     } catch (Exception e) {
       // oops we cannot throw checked exceptions
       throw new RuntimeException(e);
     }
   }

   private String getOption(String name) {
     // there is a bug in the 1.5 apt implementation:
     // http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6258929
     // this is a hack-around
     if (environment.getOptions().containsKey(name))
       return environment.getOptions().get(name);

     for (Map.Entry<String, String> entry : environment.getOptions().entrySet()) {
       String key = entry.getKey();
       String[] splitted = key.split("=");
       if (splitted[0].equals("-A" + name))
         return splitted[1];
     }
     return null;
   }

   private void createElement(Document doc, Element tagLibElement, Tag tag) {
     Element tagElement = doc.createElement("tag");
     tagLibElement.appendChild(tagElement);
     appendTextNode(doc, tagElement, "name", tag.getName(), false);
     appendTextNode(doc, tagElement, "tag-class", tag.getTldTagClass(), false);
     appendTextNode(doc, tagElement, "body-content", tag.getTldBodyContent(), false);
     appendTextNode(doc, tagElement, "description", tag.getDescription(), true);

     // save attributes
     for (TagAttribute attribute : tag.getAttributes()) {
       createElement(doc, tagElement, attribute);
     }

   }

   private void createElement(Document doc, Element tagElement, TagAttribute attribute) {
     Element attributeElement = doc.createElement("attribute");
     tagElement.appendChild(attributeElement);
     appendTextNode(doc, attributeElement, "name", attribute.getName(), false);
     appendTextNode(doc, attributeElement, "required", String.valueOf(attribute.isRequired()), false);
     appendTextNode(doc,
         attributeElement,
         "rtexprvalue",
         String.valueOf(attribute.isRtexprvalue()),
         false);
     appendTextNode(doc, attributeElement, "description", attribute.getDescription(), true);
   }

   private void appendTextNode(Document doc, Element element, String name, String text, boolean cdata) {
     Text textNode = cdata ? doc.createCDATASection(text) : doc.createTextNode(text);
     Element newElement = doc.createElement(name);
     newElement.appendChild(textNode);
     element.appendChild(newElement);
   }

   /**
    * Get values of annotation
    *
    * @param declaration
    * @param type
    *          The type of the annotation
    * @return name->value map of annotation values
    */
   private HashMap<String, Object> getValues(Declaration declaration, AnnotationTypeDeclaration type) {
     HashMap<String, Object> values = new HashMap<String, Object>();
     Collection<AnnotationMirror> annotations = declaration.getAnnotationMirrors();
     // iterate over the mirrors.

     for (AnnotationMirror mirror : annotations) {
       // if the mirror in this iteration is for our note declaration...
       if (mirror.getAnnotationType().getDeclaration().equals(type)) {
         for(AnnotationTypeElementDeclaration annotationType : mirror.getElementValues().keySet()) {
           Object value = mirror.getElementValues().get(annotationType).getValue();
           Object defaultValue = annotationType.getDefaultValue();
           values.put(annotationType.getSimpleName(), value != null ? value : defaultValue);
         }
       }
     }

     //find default values...painful
     for(AnnotationTypeElementDeclaration annotationType : type.getMethods()) {
         AnnotationValue value = annotationType.getDefaultValue();
         if(value != null) {
             String name = annotationType.getSimpleName();
             if(!values.containsKey(name))
                 values.put(name, value.getValue());
         }
     }

     return values;
   }
 }
	/*
	* $Id: $
	*
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you under the Apache License, Version 2.0 (the
	* "License"); you may not use this file except in compliance
	* with the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing,
	* software distributed under the License is distributed on an
	* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
	* KIND, either express or implied. See the License for the
	* specific language governing permissions and limitations
	* under the License.
	*/
	package org.apache.struts.annotations.taglib.apt;
	import java.io.BufferedWriter;
	import java.io.File;
	import java.io.FileOutputStream;
	import java.io.FileWriter;
	import java.io.OutputStreamWriter;
	import java.io.PrintWriter;
	import java.util.Collection;
	import java.util.HashMap;
	import java.util.Map;

	import javax.xml.parsers.DocumentBuilder;
	import javax.xml.parsers.DocumentBuilderFactory;
	import javax.xml.transform.OutputKeys;
	import javax.xml.transform.Result;
	import javax.xml.transform.Source;
	import javax.xml.transform.Transformer;
	import javax.xml.transform.TransformerFactory;
	import javax.xml.transform.dom.DOMSource;
	import javax.xml.transform.stream.StreamResult;

	import org.w3c.dom.Document;
	import org.w3c.dom.Element;
	import org.w3c.dom.Text;

	import com.sun.mirror.apt.AnnotationProcessor;
	import com.sun.mirror.apt.AnnotationProcessorEnvironment;
	import com.sun.mirror.declaration.AnnotationMirror;
	import com.sun.mirror.declaration.AnnotationTypeDeclaration;
	import com.sun.mirror.declaration.AnnotationTypeElementDeclaration;
	import com.sun.mirror.declaration.AnnotationValue;
	import com.sun.mirror.declaration.Declaration;
	import com.sun.mirror.declaration.MethodDeclaration;
	import com.sun.mirror.declaration.TypeDeclaration;

	import freemarker.template.Configuration;
	import freemarker.template.DefaultObjectWrapper;
	import freemarker.template.Template;

	public class TagAnnotationProcessor implements AnnotationProcessor {
	public static final String TAG = "org.apache.struts.annotations.StrutsTag";
	public static final String TAG_ATTRIBUTE = "org.apache.struts.annotations.StrutsTagAttribute";

	private AnnotationProcessorEnvironment environment;
	private AnnotationTypeDeclaration tagDeclaration;
	private AnnotationTypeDeclaration tagAttributeDeclaration;
	private Map<String, Tag> tags = new HashMap<String, Tag>();

	public TagAnnotationProcessor(AnnotationProcessorEnvironment env) {
	environment = env;
	tagDeclaration = (AnnotationTypeDeclaration) environment.getTypeDeclaration(TAG);
	tagAttributeDeclaration = (AnnotationTypeDeclaration) environment
	.getTypeDeclaration(TAG_ATTRIBUTE);
	}

	public void process() {
	//make sure all paramters were set
	checkOptions();

	// tags
	Collection<Declaration> tagDeclarations = environment
	.getDeclarationsAnnotatedWith(tagDeclaration);
	Collection<Declaration> attributesDeclarations = environment
	.getDeclarationsAnnotatedWith(tagAttributeDeclaration);

	// find Tags
	for (Declaration declaration : tagDeclarations) {
	// type
	TypeDeclaration typeDeclaration = (TypeDeclaration) declaration;
	String typeName = typeDeclaration.getQualifiedName();
	HashMap<String, Object> values = getValues(typeDeclaration, tagDeclaration);
	// create Tag and apply values found
	Tag tag = new Tag();
	tag.setDescription((String) values.get("description"));
	tag.setName((String) values.get("name"));
	tag.setTldBodyContent((String) values.get("tldBodyContent"));
	tag.setTldTagClass((String) values.get("tldTagClass"));
	tag.setDeclaredType(typeName);
	// add to map
	tags.put(typeName, tag);
	}

	// find Tags Attributes
	for (Declaration declaration : attributesDeclarations) {
	// type
	MethodDeclaration methodDeclaration = (MethodDeclaration) declaration;
	String typeName = methodDeclaration.getDeclaringType().getQualifiedName();
	HashMap<String, Object> values = getValues(methodDeclaration, tagAttributeDeclaration);
	// create Attribute and apply values found
	TagAttribute attribute = new TagAttribute();
	attribute.setDescription((String) values.get("description"));
	String name = (String) values.get("name");
	if(name == null \|\| name.length() == 0) {
	//get name from method
	String methodName = methodDeclaration.getSimpleName();
	name = String.valueOf(Character.toLowerCase(methodName.charAt(3))) + methodName.substring(4);
	}
	attribute.setName(name);
	attribute.setRequired((Boolean) values.get("required"));
	attribute.setRtexprvalue((Boolean) values.get("rtexprvalue"));
	attribute.setDefaultValue((String) values.get("defaultValue"));
	// add to map
	Tag parentTag = tags.get(typeName);
	if(parentTag != null)
	tags.get(typeName).addTagAttribute(attribute);
	else {
	//an abstract or base class
	parentTag = new Tag();
	parentTag.setDeclaredType(typeName);
	parentTag.setInclude(false);
	parentTag.addTagAttribute(attribute);
	tags.put(typeName, parentTag);
	}
	}

	//we can't process the hierarchy on the first pass because
	//apt does not garantees that the base classes will be processed
	//before their subclasses
	for(Map.Entry<String, Tag> entry : tags.entrySet()) {
	processHierarchy(entry.getValue());
	}

	//save
	saveAsXml();
	saveTemplates();
	}

	private void processHierarchy(Tag tag) {
	try {
	Class clazz = Class.forName(tag.getDeclaredType());
	while((clazz = clazz.getSuperclass()) != null) {
	Tag parentTag = tags.get(clazz.getName());
	//copy parent annotations to this tag
	if(parentTag != null) {
	for(TagAttribute attribute : parentTag.getAttributes()) {
	tag.addTagAttribute(attribute);
	}
	}
	}
	} catch (ClassNotFoundException e) {
	throw new RuntimeException(e);
	}
	}

	private void checkOptions() {
	if(getOption("tlibVersion") == null)
	throw new IllegalArgumentException("'tlibVersion' is missing");
	if(getOption("jspVersion") == null)
	throw new IllegalArgumentException("'jspVersion' is missing");
	if(getOption("shortName") == null)
	throw new IllegalArgumentException("'shortName' is missing");
	if(getOption("description") == null)
	throw new IllegalArgumentException("'description' is missing");
	if(getOption("displayName") == null)
	throw new IllegalArgumentException("'displayName' is missing");
	if(getOption("uri") == null)
	throw new IllegalArgumentException("'uri' is missing");
	if(getOption("outTemplatesDir") == null)
	throw new IllegalArgumentException("'outTemplatesDir' is missing");
	if(getOption("outFile") == null)
	throw new IllegalArgumentException("'outFile' is missing");
	}

	private void saveTemplates() {
	//freemarker configuration
	Configuration config = new Configuration();
	config.setClassForTemplateLoading(getClass(), "");
	config.setObjectWrapper(new DefaultObjectWrapper());

	try {
	//load template
	Template template = config.getTemplate("tag.ftl");
	String rootDir = (new File(getOption("outTemplatesDir"))).getAbsolutePath();
	for(Tag tag : tags.values()) {
	if(tag.isInclude()) {
	//model
	HashMap root = new HashMap();
	root.put("tag", tag);

	//save file
	BufferedWriter writer = new BufferedWriter(new FileWriter(new File(rootDir, tag.getName() + ".html")));
	try {
	template.process(root, writer);
	} finally {
	writer.close();
	}
	}
	}
	} catch (Exception e) {
	//oops we cannot throw checked exceptions
	throw new RuntimeException(e);
	}
	}


	private void saveAsXml() {
	DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
	DocumentBuilder builder;

	try {
	// create xml document
	builder = factory.newDocumentBuilder();
	Document document = builder.newDocument();
	document.setXmlVersion("1.0");

	// taglib
	Element tagLib = document.createElement("taglib");
	document.appendChild(tagLib);
	// tag lib attributes
	appendTextNode(document, tagLib, "tlib-version", getOption("tlibVersion"), false);
	appendTextNode(document, tagLib, "jsp-version", getOption("jspVersion"), false);
	appendTextNode(document, tagLib, "short-name", getOption("shortName"), false);
	appendTextNode(document, tagLib, "uri", getOption("uri"), false);
	appendTextNode(document, tagLib, "display-name", getOption("displayName"), false);
	appendTextNode(document, tagLib, "description", getOption("description"), true);

	// create tags
	for (Map.Entry<String, Tag> entry : tags.entrySet()) {
	Tag tag = entry.getValue();
	if(tag.isInclude())
	createElement(document, tagLib, tag);
	}

	// save to file
	TransformerFactory tf = TransformerFactory.newInstance();
	tf.setAttribute("indent-number", new Integer(2));
	Transformer transformer = tf.newTransformer();
	//if tiger would just format it :(
	//formatting bug in tiger (http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6296446)

	transformer.setOutputProperty(OutputKeys.INDENT, "yes");
	transformer.setOutputProperty(OutputKeys.DOCTYPE_PUBLIC, "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN");
	transformer.setOutputProperty(OutputKeys.DOCTYPE_SYSTEM, "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd");
	transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");

	Source source = new DOMSource(document);
	Result result = new StreamResult(new OutputStreamWriter(new FileOutputStream(getOption("outFile"))));
	transformer.transform(source, result);
	} catch (Exception e) {
	// oops we cannot throw checked exceptions
	throw new RuntimeException(e);
	}
	}

	private String getOption(String name) {
	// there is a bug in the 1.5 apt implementation:
	// http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6258929
	// this is a hack-around
	if (environment.getOptions().containsKey(name))
	return environment.getOptions().get(name);

	for (Map.Entry<String, String> entry : environment.getOptions().entrySet()) {
	String key = entry.getKey();
	String[] splitted = key.split("=");
	if (splitted[0].equals("-A" + name))
	return splitted[1];
	}
	return null;
	}

	private void createElement(Document doc, Element tagLibElement, Tag tag) {
	Element tagElement = doc.createElement("tag");
	tagLibElement.appendChild(tagElement);
	appendTextNode(doc, tagElement, "name", tag.getName(), false);
	appendTextNode(doc, tagElement, "tag-class", tag.getTldTagClass(), false);
	appendTextNode(doc, tagElement, "body-content", tag.getTldBodyContent(), false);
	appendTextNode(doc, tagElement, "description", tag.getDescription(), true);

	// save attributes
	for (TagAttribute attribute : tag.getAttributes()) {
	createElement(doc, tagElement, attribute);
	}

	}

	private void createElement(Document doc, Element tagElement, TagAttribute attribute) {
	Element attributeElement = doc.createElement("attribute");
	tagElement.appendChild(attributeElement);
	appendTextNode(doc, attributeElement, "name", attribute.getName(), false);
	appendTextNode(doc, attributeElement, "required", String.valueOf(attribute.isRequired()), false);
	appendTextNode(doc,
	attributeElement,
	"rtexprvalue",
	String.valueOf(attribute.isRtexprvalue()),
	false);
	appendTextNode(doc, attributeElement, "description", attribute.getDescription(), true);
	}

	private void appendTextNode(Document doc, Element element, String name, String text, boolean cdata) {
	Text textNode = cdata ? doc.createCDATASection(text) : doc.createTextNode(text);
	Element newElement = doc.createElement(name);
	newElement.appendChild(textNode);
	element.appendChild(newElement);
	}

	/**
	* Get values of annotation
	*
	* @param declaration
	* @param type
	* The type of the annotation
	* @return name->value map of annotation values
	*/
	private HashMap<String, Object> getValues(Declaration declaration, AnnotationTypeDeclaration type) {
	HashMap<String, Object> values = new HashMap<String, Object>();
	Collection<AnnotationMirror> annotations = declaration.getAnnotationMirrors();
	// iterate over the mirrors.

	for (AnnotationMirror mirror : annotations) {
	// if the mirror in this iteration is for our note declaration...
	if (mirror.getAnnotationType().getDeclaration().equals(type)) {
	for(AnnotationTypeElementDeclaration annotationType : mirror.getElementValues().keySet()) {
	Object value = mirror.getElementValues().get(annotationType).getValue();
	Object defaultValue = annotationType.getDefaultValue();
	values.put(annotationType.getSimpleName(), value != null ? value : defaultValue);
	}
	}
	}

	//find default values...painful
	for(AnnotationTypeElementDeclaration annotationType : type.getMethods()) {
	AnnotationValue value = annotationType.getDefaultValue();
	if(value != null) {
	String name = annotationType.getSimpleName();
	if(!values.containsKey(name))
	values.put(name, value.getValue());
	}
	}

	return values;
	}
	}