/*
* The Apache Software License, Version 1.1
*
*
* Copyright (c) 1999 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Xalan" and "Apache Software Foundation" must
* not be used to endorse or promote products derived from this
* software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache",
* nor may "Apache" appear in their name, without prior written
* permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation and was
* originally based on software copyright (c) 1999, Lotus
* Development Corporation., http://www.lotus.com. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
/**
* $Id$
*/
package javax.xml.transform;
import java.io.IOException;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.BufferedReader;
import java.util.Properties;
import java.util.Enumeration;
/**
* A TransformerFactory instance can be used to create Transformer and Template
* objects.
*
* <p>The system property that determines which Factory implementation
* to create is named "javax.xml.transform.TransformerFactory". This
* property names a concrete subclass of the TransformerFactory abstract
* class. If the property is not defined, a platform default is be used.</p>
*/
public abstract class TransformerFactory {
/** The default property name according to the JAXP spec. */
private static final String defaultPropName =
"javax.xml.transform.TransformerFactory";
/**
* Default constructor is protected on purpose.
*/
protected TransformerFactory() {}
/**
* Obtain a new instance of a <code>TransformerFactory</code>.
* This static method creates a new factory instance
* This method uses the following ordered lookup procedure to determine
* the <code>TransformerFactory</code> implementation class to
* load:
* <ul>
* <li>
* Use the <code>javax.xml.parsers.DocumentBuilderFactory</code> system
* property.
* </li>
* <li>
* Use the JAVA_HOME(the parent directory where jdk is
* installed)/lib/jaxp.properties for a property file that contains the
* name of the implementation class keyed on the same value as the
* system property defined above.
* </li>
* <li>
* Use the Services API (as detailed in teh JAR specification), if
* available, to determine the classname. The Services API will look
* for a classname in the file
* <code>META-INF/services/javax.xml.parsers.TransformerFactory</code>
* in jars available to the runtime.
* </li>
* <li>
* Platform default <code>TransformerFactory</code> instance.
* </li>
* </ul>
*
* Once an application has obtained a reference to a <code>
* TransformerFactory</code> it can use the factory to configure
* and obtain parser instances.
*
* @return new TransformerFactory instance, never null.
*
* @throws TransformerFactoryConfigurationError
* if the implmentation is not available or cannot be instantiated.
*/
public static TransformerFactory newInstance()
throws TransformerFactoryConfigurationError {
String classname =
findFactory(defaultPropName,
"org.apache.xalan.processor.TransformerFactoryImpl");
if (classname == null) {
throw new TransformerFactoryConfigurationError(
"No default implementation found");
}
TransformerFactory factoryImpl;
try {
Class clazz = getClassForName(classname);
factoryImpl = (TransformerFactory) clazz.newInstance();
} catch (ClassNotFoundException cnfe) {
throw new TransformerFactoryConfigurationError(cnfe);
} catch (IllegalAccessException iae) {
throw new TransformerFactoryConfigurationError(iae);
} catch (InstantiationException ie) {
throw new TransformerFactoryConfigurationError(ie);
}
return factoryImpl;
}
/** a zero length Object array used in getClassForName() */
private static final Object NO_OBJS[] = new Object[0];
/** the Method object for getContextClassLoader */
private static java.lang.reflect.Method getCCL;
static {
try {
getCCL = Thread.class.getMethod("getContextClassLoader",
new Class[0]);
} catch (Exception e) {
getCCL = null;
}
}
private static Class getClassForName(String className )
throws ClassNotFoundException
{
if (getCCL != null) {
try {
ClassLoader contextClassLoader =
(ClassLoader) getCCL.invoke(Thread.currentThread(),
NO_OBJS);
return contextClassLoader.loadClass(className);
} catch (ClassNotFoundException cnfe) {
// nothing, try again with Class.forName
} catch (Exception e) {
getCCL = null; // don't try again
// fallback
}
}
return Class.forName(className);
}
/**
* Process the Source into a Transformer object. Care must
* be given not to use this object in multiple threads running concurrently.
* Different TransformerFactories can be used concurrently by different
* threads.
*
* @param source An object that holds a URI, input stream, etc.
*
* @return A Transformer object that may be used to perform a transformation
* in a single thread, never null.
*
* @exception TransformerConfigurationException May throw this during the parse
* when it is constructing the Templates object and fails.
*/
public abstract Transformer newTransformer(Source source)
throws TransformerConfigurationException;
/**
* Create a new Transformer object that performs a copy
* of the source to the result.
*
* @param source An object that holds a URI, input stream, etc.
*
* @return A Transformer object that may be used to perform a transformation
* in a single thread, never null.
*
* @exception TransformerConfigurationException May throw this during
* the parse when it is constructing the
* Templates object and fails.
*/
public abstract Transformer newTransformer()
throws TransformerConfigurationException;
/**
* Process the Source into a Templates object, which is a
* a compiled representation of the source. This Templates object
* may then be used concurrently across multiple threads. Creating
* a Templates object allows the TransformerFactory to do detailed
* performance optimization of transformation instructions, without
* penalizing runtime transformation.
*
* @param source An object that holds a URL, input stream, etc.
*
* @return A Templates object capable of being used for transformation purposes,
* never null.
*
* @exception TransformerConfigurationException May throw this during the parse when it
* is constructing the Templates object and fails.
*/
public abstract Templates newTemplates(Source source)
throws TransformerConfigurationException;
/**
* Get the stylesheet specification(s) associated
* via the xml-stylesheet processing instruction (see
* http://www.w3.org/TR/xml-stylesheet/) with the document
* document specified in the source parameter, and that match
* the given criteria. Note that it is possible to return several
* stylesheets, in which case they are applied as if they were
* a list of imports or cascades in a single stylesheet.
*
* @param source The XML source document.
* @param media The media attribute to be matched. May be null, in which
* case the prefered templates will be used (i.e. alternate = no).
* @param title The value of the title attribute to match. May be null.
* @param charset The value of the charset attribute to match. May be null.
*
* @return A Source object suitable for passing to the TransformerFactory.
*
* @throws TransformerConfigurationException.
*/
public abstract Source getAssociatedStylesheet(
Source source, String media, String title, String charset)
throws TransformerConfigurationException;
/**
* Set an object that is used by default during the transformation
* to resolve URIs used in xsl:import, or xsl:include.
*
* @param resolver An object that implements the URIResolver interface,
* or null.
*/
public abstract void setURIResolver(URIResolver resolver);
/**
* Get the object that is used by default during the transformation
* to resolve URIs used in document(), xsl:import, or xsl:include.
*
* @return The URIResolver that was set with setURIResolver.
*/
public abstract URIResolver getURIResolver();
//======= CONFIGURATION METHODS =======
/**
* Look up the value of a feature.
*
* <p>The feature name is any absolute URI.</p>
* @param name The feature name, which is an absolute URI.
* @return The current state of the feature (true or false).
*/
public abstract boolean getFeature(String name);
/**
* Allows the user to set specific attributes on the underlying
* implementation. An attribute in this context is defined to
* be an option that the implementation provides.
*
* @param name The name of the attribute.
* @param value The value of the attribute.
* @throws IllegalArgumentException thrown if the underlying
* implementation doesn't recognize the attribute.
*/
public abstract void setAttribute(String name, Object value)
throws IllegalArgumentException;
/**
* Allows the user to retrieve specific attributes on the underlying
* implementation.
* @param name The name of the attribute.
* @return value The value of the attribute.
* @throws IllegalArgumentException thrown if the underlying
* implementation doesn't recognize the attribute.
*/
public abstract Object getAttribute(String name)
throws IllegalArgumentException;
/**
* Set the error event listener for the TransformerFactory, which
* is used for the processing of transformation instructions,
* and not for the transformation itself.
*
* @param listener The new error listener.
* @throws IllegalArgumentException if listener is null.
*/
public abstract void setErrorListener(ErrorListener listener)
throws IllegalArgumentException;
/**
* Get the error event handler for the TransformerFactory.
*
* @return The current error handler, which should never be null.
*/
public abstract ErrorListener getErrorListener();
// -------------------- private methods --------------------
/**
* Avoid reading all the files when the findFactory
* method is called the second time (cache the result of
* finding the default impl).
*/
private static String foundFactory = null;
/**
* Temp debug code - this will be removed after we test everything
*/
private static boolean debug;
static {
try {
debug = System.getProperty("jaxp.debug") != null;
} catch( SecurityException ex ) {}
}
/**
* Private implementation method - will find the implementation
* class in the specified order.
*
* @param factoryId Name of the factory interface.
* @param xmlProperties Name of the properties file based on JAVA/lib.
* @param defaultFactory Default implementation, if nothing else is found.
*
* @return The factory class name.
*/
private static String findFactory(String factoryId,
String defaultFactory) {
// Use the system property first
try {
String systemProp = null;
try {
systemProp = System.getProperty(factoryId);
} catch( SecurityException se ) {}
if (systemProp != null) {
if (debug) {
System.err.println("JAXP: found system property"
+ systemProp);
}
return systemProp;
}
} catch (SecurityException se) {}
if (foundFactory != null) {
return foundFactory;
}
// try to read from $java.home/lib/jaxp.properties
try {
String javah = System.getProperty("java.home");
String configFile = javah + File.separator + "lib"
+ File.separator + "jaxp.properties";
File f = new File(configFile);
if (f.exists()) {
Properties props = new Properties();
props.load(new FileInputStream(f));
foundFactory = props.getProperty(factoryId);
if (debug) {
System.err.println("JAXP: found java.home property "
+ foundFactory);
}
if (foundFactory != null) {
return foundFactory;
}
}
} catch (Exception ex) {
if (debug) {
ex.printStackTrace();
}
}
String serviceId = "META-INF/services/" + factoryId;
// try to find services in CLASSPATH
try {
ClassLoader cl = TransformerFactory.class.getClassLoader();
InputStream is = null;
if (cl == null) {
is = ClassLoader.getSystemResourceAsStream(serviceId);
} else {
is = cl.getResourceAsStream(serviceId);
}
if (is != null) {
if (debug) {
System.err.println("JAXP: found " + serviceId);
}
BufferedReader rd =
new BufferedReader(new InputStreamReader(is));
foundFactory = rd.readLine();
rd.close();
if (debug) {
System.err.println("JAXP: loaded from services: "
+ foundFactory);
}
if ((foundFactory != null) &&!"".equals(foundFactory)) {
return foundFactory;
}
}
} catch (Exception ex) {
if (debug) {
ex.printStackTrace();
}
}
return defaultFactory;
}
}