/*
* Copyright 1999-2004 The Apache Software Foundation.
*
* Licensed 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.
*/
/*
* $Id: ExtensionHandlerJavaClass.java,v 1.22 2005/05/30 17:39:40 mkwan Exp $
*/
package org.apache.xalan.extensions;
import java.io.IOException;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Vector;
import javax.xml.transform.TransformerException;
import org.apache.xalan.templates.ElemTemplateElement;
import org.apache.xalan.templates.Stylesheet;
import org.apache.xalan.trace.ExtensionEvent;
import org.apache.xalan.transformer.TransformerImpl;
import org.apache.xpath.functions.FuncExtFunction;
import org.apache.xpath.objects.XObject;
/**
* Represents an extension namespace for XPath that handles java classes.
* It is recommended that the class URI be of the form:
* <pre>
* xalan://fully.qualified.class.name
* </pre>
* However, we do not enforce this. If the class name contains a
* a /, we only use the part to the right of the rightmost slash.
* In addition, we ignore any "class:" prefix.
* Provides functions to test a function's existence and call a function.
* Also provides functions to test an element's existence and call an
* element.
*
* @author <a href="mailto:garyp@firstech.com">Gary L Peskin</a>
* @xsl.usage internal
*/
public class ExtensionHandlerJavaClass extends ExtensionHandlerJava
{
private Class m_classObj = null;
/**
* Provides a default Instance for use by elements that need to call
* an instance method.
*/
private Object m_defaultInstance = null;
/**
* Construct a new extension namespace handler given all the information
* needed.
* @param namespaceUri the extension namespace URI that I'm implementing
* @param scriptLang language of code implementing the extension
* @param className the fully qualified class name of the class
*/
public ExtensionHandlerJavaClass(String namespaceUri,
String scriptLang,
String className)
{
super(namespaceUri, scriptLang, className);
try
{
m_classObj = getClassForName(className);
}
catch (ClassNotFoundException e)
{
// For now, just let this go. We'll catch it when we try to invoke a method.
}
}
/**
* Tests whether a certain function name is known within this namespace.
* Simply looks for a method with the appropriate name. There is
* no information regarding the arguments to the function call or
* whether the method implementing the function is a static method or
* an instance method.
* @param function name of the function being tested
* @return true if its known, false if not.
*/
public boolean isFunctionAvailable(String function)
{
Method[] methods = m_classObj.getMethods();
int nMethods = methods.length;
for (int i = 0; i < nMethods; i++)
{
if (methods[i].getName().equals(function))
return true;
}
return false;
}
/**
* Tests whether a certain element name is known within this namespace.
* Looks for a method with the appropriate name and signature.
* This method examines both static and instance methods.
* @param element name of the element being tested
* @return true if its known, false if not.
*/
public boolean isElementAvailable(String element)
{
Method[] methods = m_classObj.getMethods();
int nMethods = methods.length;
for (int i = 0; i < nMethods; i++)
{
if (methods[i].getName().equals(element))
{
Class[] paramTypes = methods[i].getParameterTypes();
if ( (paramTypes.length == 2)
&& paramTypes[0].isAssignableFrom(
org.apache.xalan.extensions.XSLProcessorContext.class)
&& paramTypes[1].isAssignableFrom(
org.apache.xalan.templates.ElemExtensionCall.class) )
{
return true;
}
}
}
return false;
}
/**
* Process a call to a function in the java class represented by
* this <code>ExtensionHandlerJavaClass<code>.
* There are three possible types of calls:
* <pre>
* Constructor:
* classns:new(arg1, arg2, ...)
*
* Static method:
* classns:method(arg1, arg2, ...)
*
* Instance method:
* classns:method(obj, arg1, arg2, ...)
* </pre>
* We use the following rules to determine the type of call made:
* <ol type="1">
* <li>If the function name is "new", call the best constructor for
* class represented by the namespace URI</li>
* <li>If the first argument to the function is of the class specified
* in the namespace or is a subclass of that class, look for the best
* method of the class specified in the namespace with the specified
* arguments. Compare all static and instance methods with the correct
* method name. For static methods, use all arguments in the compare.
* For instance methods, use all arguments after the first.</li>
* <li>Otherwise, select the best static or instance method matching
* all of the arguments. If the best method is an instance method,
* call the function using a default object, creating it if needed.</li>
* </ol>
*
* @param funcName Function name.
* @param args The arguments of the function call.
* @param methodKey A key that uniquely identifies this class and method call.
* @param exprContext The context in which this expression is being executed.
* @return the return value of the function evaluation.
* @throws TransformerException
*/
public Object callFunction (String funcName,
Vector args,
Object methodKey,
ExpressionContext exprContext)
throws TransformerException
{
Object[] methodArgs;
Object[][] convertedArgs;
Class[] paramTypes;
try
{
TransformerImpl trans = (exprContext != null) ?
(TransformerImpl)exprContext.getXPathContext().getOwnerObject() : null;
if (funcName.equals("new")) { // Handle constructor call
methodArgs = new Object[args.size()];
convertedArgs = new Object[1][];
for (int i = 0; i < methodArgs.length; i++)
{
methodArgs[i] = args.elementAt(i);
}
Constructor c = null;
if (methodKey != null)
c = (Constructor) getFromCache(methodKey, null, methodArgs);
if (c != null && !trans.getDebug())
{
try
{
paramTypes = c.getParameterTypes();
MethodResolver.convertParams(methodArgs, convertedArgs,
paramTypes, exprContext);
return c.newInstance(convertedArgs[0]);
}
catch (InvocationTargetException ite)
{
throw ite;
}
catch(Exception e)
{
// Must not have been the right one
}
}
c = MethodResolver.getConstructor(m_classObj,
methodArgs,
convertedArgs,
exprContext);
if (methodKey != null)
putToCache(methodKey, null, methodArgs, c);
if (trans != null && trans.getDebug()) {
trans.getTraceManager().fireExtensionEvent(new
ExtensionEvent(trans, c, convertedArgs[0]));
Object result;
try {
result = c.newInstance(convertedArgs[0]);
} catch (Exception e) {
throw e;
} finally {
trans.getTraceManager().fireExtensionEndEvent(new
ExtensionEvent(trans, c, convertedArgs[0]));
}
return result;
} else
return c.newInstance(convertedArgs[0]);
}
else
{
int resolveType;
Object targetObject = null;
methodArgs = new Object[args.size()];
convertedArgs = new Object[1][];
for (int i = 0; i < methodArgs.length; i++)
{
methodArgs[i] = args.elementAt(i);
}
Method m = null;
if (methodKey != null)
m = (Method) getFromCache(methodKey, null, methodArgs);
if (m != null && !trans.getDebug())
{
try
{
paramTypes = m.getParameterTypes();
MethodResolver.convertParams(methodArgs, convertedArgs,
paramTypes, exprContext);
if (Modifier.isStatic(m.getModifiers()))
return m.invoke(null, convertedArgs[0]);
else
{
// This is tricky. We get the actual number of target arguments (excluding any
// ExpressionContext). If we passed in the same number, we need the implied object.
int nTargetArgs = convertedArgs[0].length;
if (ExpressionContext.class.isAssignableFrom(paramTypes[0]))
nTargetArgs--;
if (methodArgs.length <= nTargetArgs)
return m.invoke(m_defaultInstance, convertedArgs[0]);
else
{
targetObject = methodArgs[0];
if (targetObject instanceof XObject)
targetObject = ((XObject) targetObject).object();
return m.invoke(targetObject, convertedArgs[0]);
}
}
}
catch (InvocationTargetException ite)
{
throw ite;
}
catch(Exception e)
{
// Must not have been the right one
}
}
if (args.size() > 0)
{
targetObject = methodArgs[0];
if (targetObject instanceof XObject)
targetObject = ((XObject) targetObject).object();
if (m_classObj.isAssignableFrom(targetObject.getClass()))
resolveType = MethodResolver.DYNAMIC;
else
resolveType = MethodResolver.STATIC_AND_INSTANCE;
}
else
{
targetObject = null;
resolveType = MethodResolver.STATIC_AND_INSTANCE;
}
m = MethodResolver.getMethod(m_classObj,
funcName,
methodArgs,
convertedArgs,
exprContext,
resolveType);
if (methodKey != null)
putToCache(methodKey, null, methodArgs, m);
if (MethodResolver.DYNAMIC == resolveType) { // First argument was object type
if (trans != null && trans.getDebug()) {
trans.getTraceManager().fireExtensionEvent(m, targetObject,
convertedArgs[0]);
Object result;
try {
result = m.invoke(targetObject, convertedArgs[0]);
} catch (Exception e) {
throw e;
} finally {
trans.getTraceManager().fireExtensionEndEvent(m, targetObject,
convertedArgs[0]);
}
return result;
} else
return m.invoke(targetObject, convertedArgs[0]);
}
else // First arg was not object. See if we need the implied object.
{
if (Modifier.isStatic(m.getModifiers())) {
if (trans != null && trans.getDebug()) {
trans.getTraceManager().fireExtensionEvent(m, null,
convertedArgs[0]);
Object result;
try {
result = m.invoke(null, convertedArgs[0]);
} catch (Exception e) {
throw e;
} finally {
trans.getTraceManager().fireExtensionEndEvent(m, null,
convertedArgs[0]);
}
return result;
} else
return m.invoke(null, convertedArgs[0]);
}
else
{
if (null == m_defaultInstance)
{
if (trans != null && trans.getDebug()) {
trans.getTraceManager().fireExtensionEvent(new
ExtensionEvent(trans, m_classObj));
try {
m_defaultInstance = m_classObj.newInstance();
} catch (Exception e) {
throw e;
} finally {
trans.getTraceManager().fireExtensionEndEvent(new
ExtensionEvent(trans, m_classObj));
}
} else
m_defaultInstance = m_classObj.newInstance();
}
if (trans != null && trans.getDebug()) {
trans.getTraceManager().fireExtensionEvent(m, m_defaultInstance,
convertedArgs[0]);
Object result;
try {
result = m.invoke(m_defaultInstance, convertedArgs[0]);
} catch (Exception e) {
throw e;
} finally {
trans.getTraceManager().fireExtensionEndEvent(m,
m_defaultInstance, convertedArgs[0]);
}
return result;
} else
return m.invoke(m_defaultInstance, convertedArgs[0]);
}
}
}
}
catch (InvocationTargetException ite)
{
Throwable resultException = ite;
Throwable targetException = ite.getTargetException();
if (targetException instanceof TransformerException)
throw ((TransformerException)targetException);
else if (targetException != null)
resultException = targetException;
throw new TransformerException(resultException);
}
catch (Exception e)
{
// e.printStackTrace();
throw new TransformerException(e);
}
}
/**
* Process a call to an XPath extension function
*
* @param extFunction The XPath extension function
* @param args The arguments of the function call.
* @param exprContext The context in which this expression is being executed.
* @return the return value of the function evaluation.
* @throws TransformerException
*/
public Object callFunction(FuncExtFunction extFunction,
Vector args,
ExpressionContext exprContext)
throws TransformerException
{
return callFunction(extFunction.getFunctionName(), args,
extFunction.getMethodKey(), exprContext);
}
/**
* Process a call to this extension namespace via an element. As a side
* effect, the results are sent to the TransformerImpl's result tree.
* We invoke the static or instance method in the class represented by
* by the namespace URI. If we don't already have an instance of this class,
* we create one upon the first call.
*
* @param localPart Element name's local part.
* @param element The extension element being processed.
* @param transformer Handle to TransformerImpl.
* @param stylesheetTree The compiled stylesheet tree.
* @param methodKey A key that uniquely identifies this element call.
* @throws IOException if loading trouble
* @throws TransformerException if parsing trouble
*/
public void processElement(String localPart,
ElemTemplateElement element,
TransformerImpl transformer,
Stylesheet stylesheetTree,
Object methodKey)
throws TransformerException, IOException
{
Object result = null;
Method m = (Method) getFromCache(methodKey, null, null);
if (null == m)
{
try
{
m = MethodResolver.getElementMethod(m_classObj, localPart);
if ( (null == m_defaultInstance) &&
!Modifier.isStatic(m.getModifiers()) ) {
if (transformer.getDebug()) {
transformer.getTraceManager().fireExtensionEvent(
new ExtensionEvent(transformer, m_classObj));
try {
m_defaultInstance = m_classObj.newInstance();
} catch (Exception e) {
throw e;
} finally {
transformer.getTraceManager().fireExtensionEndEvent(
new ExtensionEvent(transformer, m_classObj));
}
} else
m_defaultInstance = m_classObj.newInstance();
}
}
catch (Exception e)
{
// e.printStackTrace ();
throw new TransformerException (e.getMessage (), e);
}
putToCache(methodKey, null, null, m);
}
XSLProcessorContext xpc = new XSLProcessorContext(transformer,
stylesheetTree);
try
{
if (transformer.getDebug()) {
transformer.getTraceManager().fireExtensionEvent(m, m_defaultInstance,
new Object[] {xpc, element});
try {
result = m.invoke(m_defaultInstance, new Object[] {xpc, element});
} catch (Exception e) {
throw e;
} finally {
transformer.getTraceManager().fireExtensionEndEvent(m,
m_defaultInstance, new Object[] {xpc, element});
}
} else
result = m.invoke(m_defaultInstance, new Object[] {xpc, element});
}
catch (InvocationTargetException e)
{
Throwable targetException = e.getTargetException();
if (targetException instanceof TransformerException)
throw (TransformerException)targetException;
else if (targetException != null)
throw new TransformerException (targetException.getMessage (),
targetException);
else
throw new TransformerException (e.getMessage (), e);
}
catch (Exception e)
{
// e.printStackTrace ();
throw new TransformerException (e.getMessage (), e);
}
if (result != null)
{
xpc.outputToResultTree (stylesheetTree, result);
}
}
}