CVS Update: xmlpull-api-v1/src/java/samples

aslom       04/02/13 16:06:02

  Added:       src/java/samples CloneableFileReader.java CloneParser.java
  Log:
  Sample that demonstrates how to XmlPullParser that implements Cloneable
  Sampe cloneable file reader (not tested!)
  
  Revision  Changes    Path
  1.1                  xmlpull-api-v1/src/java/samples/CloneableFileReader.java
  
  Index: CloneableFileReader.java
  ===================================================================
  /* -*-             c-basic-offset: 4; indent-tabs-mode: nil; -*-  //------100-columns-wide------>|*/
  // for license please see accompanying LICENSE.txt file (available also at http://www.xmlpull.org/)
  
  
  import java.io.FileNotFoundException;
  import java.io.FileReader;
  import java.io.IOException;
  import java.io.Reader;
  
  /**
   * Simple Cloneable File Reader to allow cloning pull parsers efficiently.
   *
   * @author <a href="http://www.extreme.indiana.edu/~aslom/">Aleksander Slominski</a>
   */
  public class CloneableFileReader extends Reader implements Cloneable
  {
      FileReader freader;
      String filename;
      long position;
      
      public CloneableFileReader(String filename) throws FileNotFoundException {
          this.freader = new FileReader(filename);
          this.filename = filename;
      }
      
      //JDK15 covariant public CloneableFileReader clone() throws CloneNotSupportedException {
      public Object clone() throws CloneNotSupportedException {
          CloneableFileReader clone;
          try {
              clone = new CloneableFileReader(filename);
              clone.skip(position);
          } catch (IOException e) {
              throw new CloneNotSupportedException("could not clone file reader "+e);
          }
          return clone;
      }
      
      public int read(char[] cbuf,
                      int offset,
                      int length)
          throws IOException
      {
          
          int actual = freader.read(cbuf, offset, length);
          if(actual > 0) {
              position += actual;
          }
          return actual;
      }
      
      // re-implement remaining functions similar to read above...
      public void close() throws IOException {
          freader.close();
      }
      
  }
  
  
  
  
  1.1                  xmlpull-api-v1/src/java/samples/CloneParser.java
  
  Index: CloneParser.java
  ===================================================================
  /* -*-             c-basic-offset: 4; indent-tabs-mode: nil; -*-  //------100-columns-wide------>|*/
  // for license please see accompanying LICENSE.txt file (available also at http://www.xmlpull.org/)
  
  //import CloneableMXParser;
  import java.io.CharArrayReader;
  import java.io.Reader;
  import org.xmlpull.v1.XmlPullParser;
  import org.xmlpull.v1.XmlPullParserException;
  import org.xmlpull.v1.XmlPullParserFactory;
  
  /**
   * An example to demonstrate how cloneable parser can be used.
   *
   * @author <a href="http://www.extreme.indiana.edu/~aslom/">Aleksander Slominski</a>
   */
  class CloneParser {
      
      public static class CloenableCharArrayReader extends CharArrayReader implements Cloneable {
          public CloenableCharArrayReader(char buf[]) {
              super(buf);
          }
          
          public Object clone() throws CloneNotSupportedException
          {
              CloenableCharArrayReader cloned = (CloenableCharArrayReader) super.clone();
              cloned.buf = buf.clone();
              //UGLY UGLY UGLY ...
              cloned.lock = cloned;
              return cloned;
          }
      }
      
      public static void main(String[] args) throws Exception
      {
          XmlPullParserFactory factory = XmlPullParserFactory.newInstance(
              System.getProperty(XmlPullParserFactory.PROPERTY_NAME), null);
          //factory.setNamespaceAware(true);
          factory.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, true);
          
          XmlPullParser mpp = factory.newPullParser();
          
          final String XML = "<foo><baz>bar</baz><moo>maz</moo></foo>";
          
          //RecordableXmlPullParser mpp = new RecordableXmlPullParser(xpp);
          //CloneableMXParser mpp = new CloneableMXParser();
          System.out.println("parser implementation class is "+mpp.getClass());
          Reader cpp = new CloenableCharArrayReader(XML.toCharArray());
          mpp.setInput(cpp);
          mpp.next(); print(mpp);
          mpp.next(); print(mpp);
          System.out.println(">>> SPLIT POINT "+mpp);
          //CloneableMXParser m2 = (CloneableMXParser) mpp.clone();
          XmlPullParser m2 = cloneParserIfCloneable(mpp);
          mpp.next(); print(mpp);
          mpp.next(); print(mpp);
          mpp.next(); print(mpp);
          while(mpp.getEventType() != XmlPullParser.END_DOCUMENT) {
              mpp.next(); print(mpp);
          }
          System.out.println(">>> CLONED PARSER "+m2);
          //mpp.rewind();
          while(m2.getEventType() != XmlPullParser.END_DOCUMENT) {
              m2.next(); print(m2);
          }
          System.out.println(">>> END");
      }
      
      private static XmlPullParser cloneParserIfCloneable(XmlPullParser pp)
          throws CloneNotSupportedException
      {
          
          if(pp instanceof java.lang.Cloneable) {
              // due to design decisions Cloneable is emtpy interface without clone() method
              //use reflection to call clone() -- this is getting ugly!!!!
              // more background on this in http://www.artima.com/intv/issues3.html "The clone Dilemma"
              Object o;
              try {
                  o = pp.getClass().getMethod("clone", null).invoke(pp, null);
              } catch (Exception e) {
                  CloneNotSupportedException ee =
                      new CloneNotSupportedException("failed to call clone() on  "+pp+":"+e);
                  ee.initCause(e);
                  throw ee;
              }
              return (XmlPullParser) o;
          }
          throw new CloneNotSupportedException(
              "could not clone pull parser as it does not implement Cloneable "+pp.getClass());
      }
      
      private static void print(XmlPullParser pp) throws XmlPullParserException {
          int type = pp.getEventType();
          System.out.print(XmlPullParser.TYPES[type]+" ");
          if(type == XmlPullParser.START_TAG || type == XmlPullParser.END_TAG) {
              System.out.print(pp.getName());
          } else if(type == XmlPullParser.TEXT) {
              System.out.print("'"+pp.getText()+"'");
          }
          System.out.println();
      }
      
  }
  
  
  
  



 
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