code: /*
   * 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.
   */
  /*
   * $Id$
   */
  
  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.get(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.get(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);
      }
   
    }
   
  }
  