cachedxpathfunchereapi.java

来自「JAVA 所有包」· Java 代码 · 共 458 行 · 第 1/2 页

    *  @see com.sun.org.apache.xpath.internal.objects.XBoolean
    *  @see com.sun.org.apache.xpath.internal.objects.XNumber
    *  @see com.sun.org.apache.xpath.internal.objects.XString
    *  @see com.sun.org.apache.xpath.internal.objects.XRTreeFrag
    *
    * @throws TransformerException
    * @deprecated
    */
   public XObject eval(Node contextNode, Node xpathnode)
           throws TransformerException {
      return eval(contextNode, xpathnode, getStrFromNode(xpathnode),contextNode);
   }

   /**
    *  Evaluate XPath string to an XObject.
    *  XPath namespace prefixes are resolved from the namespaceNode.
    *  The implementation of this is a little slow, since it creates
    *  a number of objects each time it is called.  This could be optimized
    *  to keep the same objects around, but then thread-safety issues would arise.
    *
    *  @param contextNode The node to start searching from.
    * @param xpathnode
    * @param str
    *  @param namespaceNode The node from which prefixes in the XPath will be resolved to namespaces.
    *  @return An XObject, which can be used to obtain a string, number, nodelist, etc, should never be null.
    *  @see com.sun.org.apache.xpath.internal.objects.XObject
    *  @see com.sun.org.apache.xpath.internal.objects.XNull
    *  @see com.sun.org.apache.xpath.internal.objects.XBoolean
    *  @see com.sun.org.apache.xpath.internal.objects.XNumber
    *  @see com.sun.org.apache.xpath.internal.objects.XString
    *  @see com.sun.org.apache.xpath.internal.objects.XRTreeFrag
    *
    * @throws TransformerException
    */
   public XObject eval(Node contextNode, Node xpathnode, String str, Node namespaceNode)
           throws TransformerException {
      //  Create the XPath object.
      //String str = CachedXPathFuncHereAPI.getStrFromNode(xpathnode);

      // Since we don't have a XML Parser involved here, install some default support
      // for things like namespaces, etc.
      // (Changed from: XPathContext xpathSupport = new XPathContext();
      //    because XPathContext is weak in a number of areas... perhaps
      //    XPathContext should be done away with.)
      if (this._funcHereContext == null) {
         this._funcHereContext = new FuncHereContext(xpathnode,
                                                     this._dtmManager);
      }

      // Create an object to resolve namespace prefixes.
      // XPath namespaces are resolved from the input context node's document element
      // if it is a root node, or else the current context node (for lack of a better
      // resolution space, given the simplicity of this sample code).
      PrefixResolverDefault prefixResolver =
         new PrefixResolverDefault((namespaceNode.getNodeType()
                                    == Node.DOCUMENT_NODE)
                                   ? ((Document) namespaceNode)
                                      .getDocumentElement()
                                   : namespaceNode);

      if (str!=xpathStr) {
        if (str.indexOf("here()")>0) {
            _context.reset();
            _dtmManager=_context.getDTMManager();
        }
        xpath = createXPath(str, prefixResolver);
        xpathStr=str;
      }

      // Execute the XPath, and have it return the result
      // return xpath.execute(xpathSupport, contextNode, prefixResolver);
      int ctxtNode = this._funcHereContext.getDTMHandleFromNode(contextNode);

      return xpath.execute(this._funcHereContext, ctxtNode, prefixResolver);
   }

   /**
    *   Evaluate XPath string to an XObject.
    *   XPath namespace prefixes are resolved from the namespaceNode.
    *   The implementation of this is a little slow, since it creates
    *   a number of objects each time it is called.  This could be optimized
    *   to keep the same objects around, but then thread-safety issues would arise.
    *
    *   @param contextNode The node to start searching from.
    * @param xpathnode
    * @param str
    *   @param prefixResolver Will be called if the parser encounters namespace
    *                         prefixes, to resolve the prefixes to URLs.
    *   @return An XObject, which can be used to obtain a string, number, nodelist, etc, should never be null.
    *   @see com.sun.org.apache.xpath.internal.objects.XObject
    *   @see com.sun.org.apache.xpath.internal.objects.XNull
    *   @see com.sun.org.apache.xpath.internal.objects.XBoolean
    *   @see com.sun.org.apache.xpath.internal.objects.XNumber
    *   @see com.sun.org.apache.xpath.internal.objects.XString
    *   @see com.sun.org.apache.xpath.internal.objects.XRTreeFrag
    *
    * @throws TransformerException
    */
   public XObject eval(
           Node contextNode, Node xpathnode, String str, PrefixResolver prefixResolver)
              throws TransformerException {

      // Since we don't have a XML Parser involved here, install some default support
      // for things like namespaces, etc.
      // (Changed from: XPathContext xpathSupport = new XPathContext();
      //    because XPathContext is weak in a number of areas... perhaps
      //    XPathContext should be done away with.)
      // Create the XPath object.
      //String str = CachedXPathFuncHereAPI.getStrFromNode(xpathnode);
    if (str!=xpathStr) {
        if (str.indexOf("here()")>0) {
            _context.reset();
            _dtmManager=_context.getDTMManager();
        }
        try {
            xpath = createXPath(str, prefixResolver);
        } catch (TransformerException ex) {
            //Try to see if it is a problem with the classloader.
            Throwable th= ex.getCause();
            if (th instanceof ClassNotFoundException) {
                 if (th.getMessage().indexOf("FuncHere")>0) {
                     throw new RuntimeException(I18n.translate("endorsed.jdk1.4.0")/*,*/+ex);
                 }
              }
              throw ex;
        }
        xpathStr=str;
    }

      // Execute the XPath, and have it return the result
      if (this._funcHereContext == null) {
         this._funcHereContext = new FuncHereContext(xpathnode,
                                                     this._dtmManager);
      }

      int ctxtNode = this._funcHereContext.getDTMHandleFromNode(contextNode);

      return xpath.execute(this._funcHereContext, ctxtNode, prefixResolver);
   }

    private XPath createXPath(String str, PrefixResolver prefixResolver) throws TransformerException {
        XPath xpath = null;
        Class[] classes = new Class[]{String.class, SourceLocator.class, PrefixResolver.class, int.class,
                ErrorListener.class, FunctionTable.class};
        Object[] objects = new Object[]{str, null, prefixResolver, new Integer(XPath.SELECT), null, _funcTable};
        try {
            Constructor constructor = XPath.class.getConstructor(classes);
            xpath = (XPath) constructor.newInstance(objects);
        } catch (Throwable t) {
        }
        if (xpath == null) {
            xpath = new XPath(str, null, prefixResolver, XPath.SELECT, null);
        }
        return xpath;
    }

    /**
     * Method getStrFromNode
     *
     * @param xpathnode
     * @return the string for the node.
     */
    public static String getStrFromNode(Node xpathnode) {

       if (xpathnode.getNodeType() == Node.TEXT_NODE) {

          // we iterate over all siblings of the context node because eventually,
          // the text is "polluted" with pi's or comments
          StringBuffer sb = new StringBuffer();

          for (Node currentSibling = xpathnode.getParentNode().getFirstChild();
               currentSibling != null;
               currentSibling = currentSibling.getNextSibling()) {
             if (currentSibling.getNodeType() == Node.TEXT_NODE) {
                sb.append(((Text) currentSibling).getData());
             }
          }

          return sb.toString();
       } else if (xpathnode.getNodeType() == Node.ATTRIBUTE_NODE) {
          return ((Attr) xpathnode).getNodeValue();
       } else if (xpathnode.getNodeType() == Node.PROCESSING_INSTRUCTION_NODE) {
          return ((ProcessingInstruction) xpathnode).getNodeValue();
       }

       return null;
    }

    private static void fixupFunctionTable() {
        boolean installed = false;
        if (log.isLoggable(java.util.logging.Level.INFO))                                  log.log(java.util.logging.Level.INFO, "Registering Here function");
        /**
         * Try to register our here() implementation as internal function.
         */
        try {
            Class []args = {String.class, Expression.class};
            Method installFunction = FunctionTable.class.getMethod("installFunction", args);
            if ((installFunction.getModifiers() & Modifier.STATIC) != 0) {
                Object []params = {"here", new FuncHere()};
                installFunction.invoke(null, params);
                installed = true;
            }
        } catch (Throwable t) {
            if (log.isLoggable(java.util.logging.Level.FINE))                                     log.log(java.util.logging.Level.FINE, "Error installing function using the static installFunction method", t);
        }
        if(!installed) {
            try {
                _funcTable = new FunctionTable();
                Class []args = {String.class, Class.class};
                Method installFunction = FunctionTable.class.getMethod("installFunction", args);
                Object []params = {"here", FuncHere.class};
                installFunction.invoke(_funcTable, params);
                installed = true;
            } catch (Throwable t) {
                if (log.isLoggable(java.util.logging.Level.FINE))                                     log.log(java.util.logging.Level.FINE, "Error installing function using the static installFunction method", t);
            }
        }
        if (true) {
            if (installed) {
                if (log.isLoggable(java.util.logging.Level.FINE))                                     log.log(java.util.logging.Level.FINE, "Registered class " + FuncHere.class.getName()
                        + " for XPath function 'here()' function in internal table");
            } else {
                if (log.isLoggable(java.util.logging.Level.FINE))                                     log.log(java.util.logging.Level.FINE, "Unable to register class " + FuncHere.class.getName()
                        + " for XPath function 'here()' function in internal table");
            }
        }
    }
}