Formatter.java

package org.simpleframework.xml.util;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStreamWriter;
import java.io.Reader;
import java.io.StringReader;
import java.io.StringWriter;
import java.io.Writer;
import java.util.ArrayList;
import java.util.List;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.DOMConfiguration;
import org.w3c.dom.DOMImplementation;
import org.w3c.dom.Document;
import org.w3c.dom.ls.DOMImplementationLS;
import org.w3c.dom.ls.LSOutput;
import org.w3c.dom.ls.LSSerializer;
import org.xml.sax.InputSource;

public class Formatter {
   
   private static final String LS_FEATURE_KEY = "LS";
   private static final String LS_FEATURE_VERSION = "3.0";
   private static final String CORE_FEATURE_KEY = "Core";
   private static final String CORE_FEATURE_VERSION = "2.0";

   private final boolean preserveComments;
   
   public Formatter() {
      this(false);
   }
   
   public Formatter(boolean preserveComments) {
      this.preserveComments = preserveComments;
   }
   
   public String format(String source) {
      StringWriter writer = new StringWriter();
      format(source, writer);
      return writer.toString();
   }

   public void format(String source, Writer writer) {
      try {
         DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
         factory.setValidating(false);
         DocumentBuilder builder = factory.newDocumentBuilder();       
         Reader reader = new StringReader(source);
         InputSource input = new InputSource(reader);
         Document document = builder.parse(input);

         format(document, writer);
     } catch (Exception e) {
         throw new RuntimeException(e);
     }
   }

   private void format(Document document, Writer writer) {
      DOMImplementation implementation = document.getImplementation();

      if(implementation.hasFeature(LS_FEATURE_KEY, LS_FEATURE_VERSION) && implementation.hasFeature(CORE_FEATURE_KEY, CORE_FEATURE_VERSION)) {
         DOMImplementationLS implementationLS = (DOMImplementationLS) implementation.getFeature(LS_FEATURE_KEY, LS_FEATURE_VERSION);
         LSSerializer serializer = implementationLS.createLSSerializer();
         DOMConfiguration configuration = serializer.getDomConfig();
         
         configuration.setParameter("format-pretty-print", Boolean.TRUE);
         configuration.setParameter("comments", preserveComments);
         
         LSOutput output = implementationLS.createLSOutput();
         output.setEncoding("UTF-8");
         output.setCharacterStream(writer);
         serializer.write(document, output);
      }
   }
  
  private String read(File file) throws IOException {
     ByteArrayOutputStream buffer = new ByteArrayOutputStream();
     InputStream source = new FileInputStream(file);
     byte[] chunk = new byte[1024];
     int count = 0;
     
     while((count = source.read(chunk)) != -1) {
        buffer.write(chunk, 0, count);
     }
     return buffer.toString("UTF-8");     
  }
  
  /**
   * Scripts to execute the XML formatter.
   * 
   * #!/bin/bash
   * xml.bat $1 $2 $3    
   * 
   * echo off
   * java -jar c:/start/bin/xml.jar %1 %2 %3 %4
   * 
   * @param list arguments to the formatter
   */
  public static void main(String list[]) throws Exception {   
     List<String> values = new ArrayList<String>();
     
     for(String argument : list) {
        if(argument != null && argument.trim().length() > 0) {
           values.add(argument.trim());
        }
     }
     if(values.size() == 0) {
        throw new FileNotFoundException("File needs to be specified as an argument");
     }  
     Formatter formatter = new Formatter();
     File file = new File(values.get(0));     
     String source = formatter.read(file); // read before opening for write
     
     if(values.size() == 1) {
        formatter.format(source, new OutputStreamWriter(System.out));
     }
     else if(values.size() == 2) {
        formatter.format(source, new OutputStreamWriter(new FileOutputStream(new File(values.get(1)))));     
     }
     else {
        StringBuilder builder = new StringBuilder();
        for(String value : values) {
           builder.append("'").append(value).append("'");
        }
        throw new IllegalArgumentException("At most two arguments can be specified, you specified "+builder);
     }
  }
}