Tomcat example source code file (DOMWriter.java)

This example Tomcat source code file (DOMWriter.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Tomcat tags/keywords

attr, attr, default, dom, domwriter, encoding, encoding, io, mime2java_encodings, printwriter, printwriter_encoding, printwriter_encoding, string, string, utf-16, utf8

The Tomcat DOMWriter.java source 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.
 */

package org.apache.catalina.util;

import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.io.Writer;

import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

/**
 * A sample DOM writer. This sample program illustrates how to
 * traverse a DOM tree in order to print a document that is parsed.
 */
public class DOMWriter {

   //
   // Data
   //

   /** Default Encoding */
   private static  String
   PRINTWRITER_ENCODING = "UTF8";

   private static String MIME2JAVA_ENCODINGS[] =
    { "Default", "UTF-8", "US-ASCII", "ISO-8859-1", "ISO-8859-2", "ISO-8859-3", "ISO-8859-4",
      "ISO-8859-5", "ISO-8859-6", "ISO-8859-7", "ISO-8859-8", "ISO-8859-9", "ISO-2022-JP",
      "SHIFT_JIS", "EUC-JP","GB2312", "BIG5", "EUC-KR", "ISO-2022-KR", "KOI8-R", "EBCDIC-CP-US",
      "EBCDIC-CP-CA", "EBCDIC-CP-NL", "EBCDIC-CP-DK", "EBCDIC-CP-NO", "EBCDIC-CP-FI", "EBCDIC-CP-SE",
      "EBCDIC-CP-IT", "EBCDIC-CP-ES", "EBCDIC-CP-GB", "EBCDIC-CP-FR", "EBCDIC-CP-AR1",
      "EBCDIC-CP-HE", "EBCDIC-CP-CH", "EBCDIC-CP-ROECE","EBCDIC-CP-YU",
      "EBCDIC-CP-IS", "EBCDIC-CP-AR2", "UTF-16"
    };

   /** Output qualified names */
   private boolean qualifiedNames = true;

   /** Print writer. */
   protected PrintWriter out;

   /** Canonical output. */
   protected boolean canonical;


   public DOMWriter(String encoding, boolean canonical)
   throws UnsupportedEncodingException {
      out = new PrintWriter(new OutputStreamWriter(System.out, encoding));
      this.canonical = canonical;
   } // <init>(String,boolean)

   //
   // Constructors
   //

   /** Default constructor. */
   public DOMWriter(boolean canonical) throws UnsupportedEncodingException {
      this( getWriterEncoding(), canonical);
   }

    public DOMWriter(Writer writer, boolean canonical) {
        out = new PrintWriter(writer);
        this.canonical = canonical;
    }

   public boolean getQualifiedNames() {
      return this.qualifiedNames;
   }

   public void setQualifiedNames(boolean qualifiedNames) {
      this.qualifiedNames = qualifiedNames;
   }

   public static String getWriterEncoding( ) {
      return (PRINTWRITER_ENCODING);
   }// getWriterEncoding

   public static void  setWriterEncoding( String encoding ) {
      if( encoding.equalsIgnoreCase( "DEFAULT" ) )
         PRINTWRITER_ENCODING  = "UTF8";
      else if( encoding.equalsIgnoreCase( "UTF-16" ) )
         PRINTWRITER_ENCODING  = "Unicode";
      else
         PRINTWRITER_ENCODING = MIME2Java.convert( encoding );
   }// setWriterEncoding


   public static boolean isValidJavaEncoding( String encoding ) {
      for ( int i = 0; i < MIME2JAVA_ENCODINGS.length; i++ )
         if ( encoding.equals( MIME2JAVA_ENCODINGS[i] ) )
            return (true);

      return (false);
   }// isValidJavaEncoding


   /** Prints the specified node, recursively. */
   public void print(Node node) {

      // is there anything to do?
      if ( node == null ) {
         return;
      }

      int type = node.getNodeType();
      switch ( type ) {
         // print document
         case Node.DOCUMENT_NODE: {
               if ( !canonical ) {
                  String  Encoding = getWriterEncoding();
                  if( Encoding.equalsIgnoreCase( "DEFAULT" ) )
                     Encoding = "UTF-8";
                  else if( Encoding.equalsIgnoreCase( "Unicode" ) )
                     Encoding = "UTF-16";
                  else
                     Encoding = MIME2Java.reverse( Encoding );

                  out.println("<?xml version=\"1.0\" encoding=\""+
                           Encoding + "\"?>");
               }
               print(((Document)node).getDocumentElement());
               out.flush();
               break;
            }

            // print element with attributes
         case Node.ELEMENT_NODE: {
               out.print('<');
               if (this.qualifiedNames) { 
                  out.print(node.getNodeName());
               } else {
                  out.print(node.getLocalName());
               }
               Attr attrs[] = sortAttributes(node.getAttributes());
               for ( int i = 0; i < attrs.length; i++ ) {
                  Attr attr = attrs[i];
                  out.print(' ');
                  if (this.qualifiedNames) {
                     out.print(attr.getNodeName());
                  } else {
                     out.print(attr.getLocalName());
                  }
                  
                  out.print("=\"");
                  out.print(normalize(attr.getNodeValue()));
                  out.print('"');
               }
               out.print('>');
               NodeList children = node.getChildNodes();
               if ( children != null ) {
                  int len = children.getLength();
                  for ( int i = 0; i < len; i++ ) {
                     print(children.item(i));
                  }
               }
               break;
            }

            // handle entity reference nodes
         case Node.ENTITY_REFERENCE_NODE: {
               if ( canonical ) {
                  NodeList children = node.getChildNodes();
                  if ( children != null ) {
                     int len = children.getLength();
                     for ( int i = 0; i < len; i++ ) {
                        print(children.item(i));
                     }
                  }
               } else {
                  out.print('&');
                  if (this.qualifiedNames) {
                     out.print(node.getNodeName());
                  } else {
                     out.print(node.getLocalName());
                  }
                  out.print(';');
               }
               break;
            }

            // print cdata sections
         case Node.CDATA_SECTION_NODE: {
               if ( canonical ) {
                  out.print(normalize(node.getNodeValue()));
               } else {
                  out.print("<![CDATA[");
                  out.print(node.getNodeValue());
                  out.print("]]>");
               }
               break;
            }

            // print text
         case Node.TEXT_NODE: {
               out.print(normalize(node.getNodeValue()));
               break;
            }

            // print processing instruction
         case Node.PROCESSING_INSTRUCTION_NODE: {
               out.print("<?");
               if (this.qualifiedNames) {
                  out.print(node.getNodeName());
               } else {
                  out.print(node.getLocalName());
               }
               
               String data = node.getNodeValue();
               if ( data != null && data.length() > 0 ) {
                  out.print(' ');
                  out.print(data);
               }
               out.print("?>");
               break;
            }
      }

      if ( type == Node.ELEMENT_NODE ) {
         out.print("</");
         if (this.qualifiedNames) {
            out.print(node.getNodeName());
         } else {
            out.print(node.getLocalName());
         }
         out.print('>');
      }

      out.flush();

   } // print(Node)

   /** Returns a sorted list of attributes. */
   protected Attr[] sortAttributes(NamedNodeMap attrs) {

      int len = (attrs != null) ? attrs.getLength() : 0;
      Attr array[] = new Attr[len];
      for ( int i = 0; i < len; i++ ) {
         array[i] = (Attr)attrs.item(i);
      }
      for ( int i = 0; i < len - 1; i++ ) {
         String name = null;
         if (this.qualifiedNames) {
            name  = array[i].getNodeName();
         } else {
            name  = array[i].getLocalName();
         }
         int    index = i;
         for ( int j = i + 1; j < len; j++ ) {
            String curName = null;
            if (this.qualifiedNames) {
               curName = array[j].getNodeName();
            } else {
               curName = array[j].getLocalName();
            }
            if ( curName.compareTo(name) < 0 ) {
               name  = curName;
               index = j;
            }
         }
         if ( index != i ) {
            Attr temp    = array[i];
            array[i]     = array[index];
            array[index] = temp;
         }
      }

      return (array);

   } // sortAttributes(NamedNodeMap):Attr[]


   /** Normalizes the given string. */
   protected String normalize(String s) {
      StringBuffer str = new StringBuffer();

      int len = (s != null) ? s.length() : 0;
      for ( int i = 0; i < len; i++ ) {
         char ch = s.charAt(i);
         switch ( ch ) {
            case '<': {
                  str.append("<");
                  break;
               }
            case '>': {
                  str.append(">");
                  break;
               }
            case '&': {
                  str.append("&");
                  break;
               }
            case '"': {
                  str.append(""");
                  break;
               }
            case '\r':
            case '\n': {
                  if ( canonical ) {
                     str.append("&#");
                     str.append(Integer.toString(ch));
                     str.append(';');
                     break;
                  }
                  // else, default append char
               }
            default: {
                  str.append(ch);
               }
         }
      }

      return (str.toString());

   } // normalize(String):String

   private static void printValidJavaEncoding() {
      System.err.println( "    ENCODINGS:" );
      System.err.print( "   " );
      for( int i = 0;
                     i < MIME2JAVA_ENCODINGS.length; i++) {
         System.err.print( MIME2JAVA_ENCODINGS[i] + " " );
      if( (i % 7 ) == 0 ){
         System.err.println();
         System.err.print( "   " );
         }
      }

   } // printJavaEncoding()

}