XMP metadata dumper

XMP is a metatdata format from Adobe. One way to add and edit XMP is with PixVue. This is a minimalist XMP extractor/dumper for the jpeg format.

import java.io.*;

public class XMPDumper {
  
   public static void main(String[] args) throws IOException {
      File f = new File("myimage.jpg");
      String xmp = new XMPDumper().getXMP(f);
      System.out.println(xmp);
   }

   public String getXMP(File f) 
      throws IOException {
     FileInputStream is = new FileInputStream(f);
     int i=0; String result=null;
     while ((i=is.read()) != -1)
       if (i==0xFF && is.read()==0xE1) {
         result = checkNamespace(is);
         if (result!=null) break;
       }
     return result;
   }

   public static final String namespace = 
     "http://ns.adobe.com/xap/1.0/";
   
   private String checkNamespace(FileInputStream is) 
      throws IOException {
     String s = getSegment(is);
     return (s.startsWith(namespace)) ? s.substring(29) : null;
   }
   
   private String getSegment(InputStream is) 
      throws IOException {
     DataInputStream dis = new DataInputStream(is);
     byte[] buffer = new byte[dis.readShort()-2];
     dis.read(buffer);
     return new String(buffer);
   }
}