/**************************************************************************************
* Copyright (c) Jonas Bon�r, Alexandre Vasseur. All rights reserved. *
* http://aspectwerkz.codehaus.org *
* ---------------------------------------------------------------------------------- *
* The software in this package is published under the terms of the LGPL license *
* a copy of which has been included with this distribution in the license.txt file. *
**************************************************************************************/
package org.codehaus.aspectwerkz.definition;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Iterator;
import java.util.List;
import org.codehaus.aspectwerkz.exception.DefinitionException;
import org.codehaus.aspectwerkz.exception.WrappedRuntimeException;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
/**
* Parses the XML definition file using <tt>dom4j</tt>.
*
* @author <a href="mailto:jboner@codehaus.org">Jonas Bon�r</a>
*/
public class XmlParser {
/**
* The current DTD public id. The matching dtd will be searched as a resource.
*/
private final static String DTD_PUBLIC_ID = "-//AspectWerkz//DTD 0.10//EN";
private final static String DTD_PUBLIC_ID_ALIAS = "-//AspectWerkz//DTD//EN";
/**
* The timestamp, holding the last time that the definition was parsed.
*/
private static File s_timestamp = new File(".timestamp");
/**
* The AspectWerkz definitions.
*/
private static List s_definitions = null;
/**
*
*
* @param definitionFile the definition file
* @return the definitions
*/
public static List getAspectClassNames(final File definitionFile) {
if (definitionFile == null) {
throw new IllegalArgumentException("definition file can not be null");
}
if (!definitionFile.exists()) {
throw new DefinitionException("definition file " + definitionFile.toString() + " does not exist");
}
try {
Document document = createDocument(definitionFile.toURL());
return DocumentParser.parseAspectClassNames(document);
}
catch (MalformedURLException e) {
throw new DefinitionException(definitionFile + " does not exist");
}
catch (DocumentException e) {
throw new DefinitionException("XML definition file <" + definitionFile + "> has errors: " + e.toString());
}
}
/**
*
* @param stream the input stream containing the document
* @return the definitions
*/
public static List getAspectClassNames(final InputStream stream) {
try {
Document document = createDocument(stream);
return DocumentParser.parseAspectClassNames(document);
}
catch (DocumentException e) {
throw new DefinitionException("XML definition file on classpath has errors: " + e.toString());
}
}
/**
* Parses the XML definition file, only if it has been updated. Uses a timestamp to check for modifications.
*
* @param loader the current class loader
* @param definitionFile the definition file
* @param isDirty flag to mark the the definition as updated or not
* @return the definitions
*/
public static List parse(final ClassLoader loader, final File definitionFile, boolean isDirty) {
if (definitionFile == null) {
throw new IllegalArgumentException("definition file can not be null");
}
if (!definitionFile.exists()) {
throw new DefinitionException("definition file " + definitionFile.toString() + " does not exist");
}
// if definition is not updated; don't parse but return it right away
if (isNotUpdated(definitionFile)) {
isDirty = false;
return s_definitions;
}
// updated definition, ready to be parsed
try {
Document document = createDocument(definitionFile.toURL());
s_definitions = DocumentParser.parse(loader, document);
setParsingTimestamp();
isDirty = true;
return s_definitions;
}
catch (MalformedURLException e) {
throw new DefinitionException(definitionFile + " does not exist");
}
catch (DocumentException e) {
throw new DefinitionException("XML definition file <" + definitionFile + "> has errors: " + e.toString());
}
}
/**
* Parses the XML definition file retrieved from an input stream.
*
* @param loader the current class loader
* @param stream the input stream containing the document
* @return the definitions
*/
public static List parse(final ClassLoader loader, final InputStream stream) {
try {
Document document = createDocument(stream);
s_definitions = DocumentParser.parse(loader, document);
return s_definitions;
}
catch (DocumentException e) {
throw new DefinitionException("XML definition file on classpath has errors: " + e.getMessage());
}
}
/**
* Parses the XML definition file not using the cache.
*
* @param loader the current class loader
* @param url the URL to the definition file
* @return the definition object
*/
public static List parseNoCache(final ClassLoader loader, final URL url) {
try {
Document document = createDocument(url);
s_definitions = DocumentParser.parse(loader, document);
return s_definitions;
}
catch (Exception e) {
throw new WrappedRuntimeException(e);
}
}
/**
* Merges two DOM documents.
*
* @param document1 the first document
* @param document2 the second document
* @return the definition merged document
*/
public static Document mergeDocuments(final Document document1, final Document document2) {
if (document2 == null && document1 != null) {
return document1;
}
if (document1 == null && document2 != null) {
return document2;
}
if (document1 == null && document2 == null) {
return null;
}
try {
Element root1 = document1.getRootElement();
Element root2 = document2.getRootElement();
for (Iterator it1 = root2.elementIterator(); it1.hasNext();) {
Element element = (Element)it1.next();
element.setParent(null);
root1.add(element);
}
}
catch (Exception e) {
throw new WrappedRuntimeException(e);
}
return document1;
}
/**
* Creates a DOM document.
*
* @param url the URL to the file containing the XML
* @return the DOM document
* @throws DocumentException
* @throws DocumentException
*/
public static Document createDocument(final URL url) throws DocumentException {
SAXReader reader = new SAXReader();
setEntityResolver(reader);
return reader.read(url);
}
/**
* Creates a DOM document.
*
* @param stream the stream containing the XML
* @return the DOM document
* @throws DocumentException
* @throws DocumentException
*/
public static Document createDocument(final InputStream stream) throws DocumentException {
SAXReader reader = new SAXReader();
setEntityResolver(reader);
return reader.read(stream);
}
/**
* Sets the entity resolver which is created based on the DTD from in the root dir of the AspectWerkz distribution.
*
* @param reader the reader to set the resolver in
*/
private static void setEntityResolver(final SAXReader reader) {
EntityResolver resolver = new EntityResolver() {
public InputSource resolveEntity(String publicId, String systemId) {
if (publicId.equals(DTD_PUBLIC_ID) || publicId.equals(DTD_PUBLIC_ID_ALIAS)) {
InputStream in = getClass().getResourceAsStream("/aspectwerkz.dtd");
if (in == null) {
System.err.println("AspectWerkz - WARN - could not open DTD");
return new InputSource();
}
else {
return new InputSource(in);
}
}
else {
System.err.println(
"AspectWerkz - WARN - deprecated DTD " + publicId + " - consider upgrading to " +
DTD_PUBLIC_ID
);
return new InputSource();// avoid null pointer exception
}
}
};
reader.setEntityResolver(resolver);
}
/**
* Checks if the definition file has been updated since the last parsing.
*
* @param definitionFile the definition file
* @return boolean
*/
private static boolean isNotUpdated(final File definitionFile) {
return definitionFile.lastModified() < getParsingTimestamp() && s_definitions != null;
}
/**
* Sets the timestamp for the latest parsing of the definition file.
*/
private static void setParsingTimestamp() {
final long newModifiedTime = System.currentTimeMillis();
s_timestamp.setLastModified(newModifiedTime);
}
/**
* Returns the timestamp for the last parsing of the definition file.
*
* @return the timestamp
*/
private static long getParsingTimestamp() {
final long modifiedTime = s_timestamp.lastModified();
if (modifiedTime == 0L) {
// no timestamp, create a new one
try {
s_timestamp.createNewFile();
}
catch (IOException e) {
throw new RuntimeException("could not create timestamp file: " + s_timestamp.getAbsolutePath());
}
}
return modifiedTime;
}
}