xmlserialization.java

代码是一个分类器的实现,其中使用了部分weka的源代码。可以将项目导入eclipse运行

     
      result      = o;
      descriptors = getDescriptors(result);
      methodName  = child.getAttribute(ATT_NAME);

      // in ignore list?
      if (m_Properties.isIgnored(getPath(child)))
         return result;
      
      // in ignore list of class?
      if (m_Properties.isIgnored(result, getPath(child)))
        return result;
      
      // is it allowed?
      if (!m_Properties.isAllowed(result, methodName))
        return result;
      
      descriptor = (PropertyDescriptor) descriptors.get(methodName);

      // unknown property?
      if (descriptor == null) {
         if (!m_CustomMethods.read().contains(methodName))
            System.out.println("WARNING: unknown property '" + name + "." + methodName + "'!");
         return result;
      }
      
      method     = descriptor.getWriteMethod();
      methodArgs = new Object[1];
      tmpResult  = invokeReadFromXML(child);
      paramClass = method.getParameterTypes()[0];
      
      // array?
      if (paramClass.isArray()) {
         // no data?
         if (Array.getLength(tmpResult) == 0)
           return result;
         methodArgs[0] = (Object[]) tmpResult;
      }
      // non-array
      else {
         methodArgs[0] = tmpResult;
      }

      method.invoke(result, methodArgs);
     
      return result;
   }
   
   /**
    * returns an array with the dimensions of the array stored in XML
    * @param node the node to determine the dimensions for
    * @return the dimensions of the array
    */
   protected int[] getArrayDimensions(Element node) {
     Vector         children;
     Vector         tmpVector;      
     int[]          tmp;
     int[]          result;
     int            i;
     
     // have we reached the innermost dimension?
     if (stringToBoolean(node.getAttribute(ATT_ARRAY)))
       children = XMLDocument.getChildTags(node);
     else
       children = null;
     
     if (children != null) {
       tmpVector = new Vector();

       if (children.size() > 0) {
         // are children also arrays?
         tmp = getArrayDimensions((Element) children.get(0));
         
         // further dimensions
         if (tmp != null) {
           for (i = tmp.length - 1; i >= 0; i--)
             tmpVector.add(new Integer(tmp[i]));
         }
  
         // add current dimension
         tmpVector.add(0, new Integer(children.size()));
       }
       else {
         tmpVector.add(new Integer(0));
       }
       
       // generate result
       result = new int[tmpVector.size()];
       for (i = 0; i < result.length; i++)
         result[i] = ((Integer) tmpVector.get(tmpVector.size() - i - 1)).intValue();
     }
     else {
       result = null;
     }
     
     return result;
   }
   
   /**
    * builds the object from the given DOM node. 
    * (only public due to reflection) 
    * 
    * @param node the associated XML node
    * @return the instance created from the XML description
    * @throws Exception if instantiation fails 
    */
   public Object readFromXML(Element node) throws Exception {
      String               classname;
      String               name;
      boolean              primitive;
      boolean              array;
      boolean              isnull;
      Class                cls;
      Vector               children;
      Object               result;
      int                  i;
      Constructor          constructor;
      Class[]              methodClasses;
      Object[]             methodArgs;
      Element              child;
           
      // for debugging only
      if (DEBUG)
         trace(new Throwable(), node.getAttribute(ATT_NAME));

      m_CurrentNode = node;
      
      result    = null;
      
      name      = node.getAttribute(ATT_NAME);
      classname = node.getAttribute(ATT_CLASS);
      primitive = stringToBoolean(node.getAttribute(ATT_PRIMITIVE));
      array     = stringToBoolean(node.getAttribute(ATT_ARRAY));
      isnull    = stringToBoolean(node.getAttribute(ATT_NULL));

      // special handling of null
      if (isnull)
        return result;

      children  = XMLDocument.getChildTags(node);
      cls       = determineClass(classname);
      
      // array
      if (array) {
         result = Array.newInstance(cls, getArrayDimensions(node));
         for (i = 0; i < children.size(); i++) {
            child = (Element) children.get(i);
            Array.set(result, Integer.parseInt(child.getAttribute(ATT_NAME)), invokeReadFromXML(child));
         }
      }
      // non-array
      else {
         // primitive/String-constructor
         if (children.size() == 0) {
            // primitive
            if (primitive) {
               result = getPrimitive(node);
            }
            // assumed String-constructor
            else {
               methodClasses    = new Class[1];
               methodClasses[0] = String.class;
               methodArgs       = new Object[1];
               methodArgs[0]    = XMLDocument.getContent(node);
               try {
                  constructor   = cls.getConstructor(methodClasses);
                  result        = constructor.newInstance(methodArgs);
               }
               catch (Exception e) {
                  // if it's not a class with String constructor, let's try standard constructor
                  try {
                     result = cls.newInstance();
                  }
                  catch (Exception e2) {
                     // sorry, can't instantiate!
                     result = null;
                     System.out.println("ERROR: Can't instantiate '" + classname + "'!");
                  }
               }
            }
         }
         // normal get/set methods
         else {
            result = cls.newInstance();
            for (i = 0; i < children.size(); i++)
              result = readFromXML(result, name, (Element) children.get(i));
         }
      }
            
      return result;
   }
   
   /**
    * either invokes a custom method to read a specific property/class or the standard
    * method <code>readFromXML(Element)</code>
    * 
    * @param node the associated XML node
    * @return the instance created from the XML description
    * @throws Exception if instantiation fails
    */
   protected Object invokeReadFromXML(Element node) throws Exception {
      Method         method;
      Class[]        methodClasses;
      Object[]       methodArgs;
      boolean        array;
      boolean        useDefault;

      useDefault = false;
      method     = null;
      m_CurrentNode = node;
      
      try {
         // special handling of null values
         if (stringToBoolean(node.getAttribute(ATT_NULL)))
           useDefault = true;
        
         if (!useDefault) {
            array = stringToBoolean(node.getAttribute(ATT_ARRAY));
           
            // display name?
            if (m_CustomMethods.read().contains(node.getAttribute(ATT_NAME)))
               method = (Method) m_CustomMethods.read().get(node.getAttribute(ATT_NAME));
            else
            // class name?
            if ( (!array) && (m_CustomMethods.read().contains(determineClass(node.getAttribute(ATT_CLASS)))) )
               method = (Method) m_CustomMethods.read().get(determineClass(node.getAttribute(ATT_CLASS)));
            else
               method = null;
            
            useDefault = (method == null);
         }

         // custom method
         if (!useDefault) {
            methodClasses    = new Class[1];
            methodClasses[0] = Element.class;
            methodArgs       = new Object[1];
            methodArgs[0]    = node;
            return method.invoke(this, methodArgs);
         }
         // standard
         else {
            return readFromXML(node);
         }
      }
      catch (Exception e) {
         if (DEBUG)
            e.printStackTrace();
         
         if (m_CurrentNode != null) {
           System.out.println("Happened near: " + getPath(m_CurrentNode));
           // print it only once!
           m_CurrentNode = null;
         }
         System.out.println("PROBLEM (read): " + node.getAttribute("name"));

         throw (Exception) e.fillInStackTrace();
      }
   }
   
   /**
    * additional pre-processing can happen in derived classes before the 
    * actual reading from XML (working on the raw XML). right now it does 
    * nothing with the document.
    * 
    * @param document 	the document to pre-process
    * @return the processed object
    * @throws Exception if post-processing fails
    */
   protected Document readPreProcess(Document document) throws Exception {
      return document;
   }
   
   /**
    * additional post-processing can happen in derived classes after reading 
    * from XML. right now it only returns the object as it is.
    * 
    * @param o the object to perform some additional processing on
    * @return the processed object
    * @throws Exception if post-processing fails
    */
   protected Object readPostProcess(Object o) throws Exception {
      return o;
   }

   /**
    * returns the given DOM document as an instance of the specified class
    * 
    * @param document the parsed DOM document representing the object
    * @return the XML as object 
    * @throws Exception if object instantiation fails
    */
   public Object fromXML(Document document) throws Exception {
      if (!document.getDocumentElement().getNodeName().equals(ROOT_NODE))
         throw new Exception("Expected '" + ROOT_NODE + "' as root element, but found '" + document.getDocumentElement().getNodeName() + "'!");
      m_Document.setDocument(readPreProcess(document));
      checkVersion();
      return readPostProcess(invokeReadFromXML(m_Document.getDocument().getDocumentElement()));
   }
   
   /**
    * parses the given XML string (can be XML or a filename) and returns an
    * Object generated from the representation
    * 
    * @param xml the xml to parse (if "<?xml" is not found then it is considered a file)
    * @return the generated instance
    * @throws Exception if something goes wrong with the parsing
    */
   public Object read(String xml) throws Exception {
      return fromXML(m_Document.read(xml));
   }
   
   /**
    * parses the given file and returns a DOM document
    * 
    * @param file the XML file to parse
    * @return the parsed DOM document
    * @throws Exception if something goes wrong with the parsing
    */
   public Object read(File file) throws Exception {
      return fromXML(m_Document.read(file));
   }
   
   /**
    * parses the given stream and returns a DOM document
    * 
    * @param stream the XML stream to parse
    * @return the parsed DOM document
    * @throws Exception if something goes wrong with the parsing
    */
   public Object read(InputStream stream) throws Exception {
      return fromXML(m_Document.read(stream));
   }
   
   /**
    * parses the given reader and returns a DOM document
    * 
    * @param reader the XML reader to parse
    * @return the parsed DOM document
    * @throws Exception if something goes wrong with the parsing
    */
   public Object read(Reader reader) throws Exception {
      return fromXML(m_Document.read(reader));
   }
   
   
   /**
    * writes the given object into the file
    * 
    * @param file the filename to write to
    * @param o the object to serialize as XML
    * @throws Exception if something goes wrong with the parsing
    */
   public void write(String file, Object o) throws Exception {
      toXML(o).write(file);
   }
   
   /**
    * writes the given object into the file
    * 
    * @param file the filename to write to
    * @param o the object to serialize as XML
    * @throws Exception if something goes wrong with the parsing
    */
   public void write(File file, Object o) throws Exception {
      toXML(o).write(file);
   }
   
   /**
    * writes the given object into the stream
    * 
    * @param stream the filename to write to
    * @param o the object to serialize as XML
    * @throws Exception if something goes wrong with the parsing
    */
   public void write(OutputStream stream, Object o) throws Exception {
      toXML(o).write(stream);
   }
   
   /**
    * writes the given object into the writer
    * 
    * @param writer the filename to write to
    * @param o the object to serialize as XML
    * @throws Exception if something goes wrong with the parsing
    */
   public void write(Writer writer, Object o) throws Exception {
      toXML(o).write(writer);
   }
   
   /**
    * for testing only. if the first argument is a filename with ".xml"
    * as extension it tries to generate an instance from the XML description
    * and does a <code>toString()</code> of the generated object.
    */
   public static void main(String[] args) throws Exception {
      if (args.length > 0) {
         // read xml and print
         if (args[0].toLowerCase().endsWith(".xml")) {
            System.out.println(new XMLSerialization().read(args[0]).toString());
         }
         // read binary and print generated XML
         else {
            // read
            FileInputStream fi = new FileInputStream(args[0]);
            ObjectInputStream oi = new ObjectInputStream(
                                   new BufferedInputStream(fi));
            Object o = oi.readObject();
            oi.close();
            // print to stdout
            //new XMLSerialization().write(System.out, o);
            new XMLSerialization().write(new BufferedOutputStream(new FileOutputStream(args[0] + ".xml")), o);
            // print to binary file
            FileOutputStream fo = new FileOutputStream(args[0] + ".exp");
            ObjectOutputStream oo = new ObjectOutputStream(
                                   new BufferedOutputStream(fo));
            oo.writeObject(o);
            oo.close();
         }
      }
   }
}