Re: object dumper

From:

ram@zedat.fu-berlin.de (Stefan Ram)

Newsgroups:

comp.lang.java.programmer

Date:

3 Dec 2006 00:05:25 GMT

Message-ID:

"Matt Humphrey" <matth@ivizNOSPAM.com> writes:

"tom arnall" <kloro2006@gmail.com> wrote in message
news:457202cb$0$20558$88260bb3@free.teranews.com...

does anyone know of an object dumper that enables easy output of fields
and
values info to stdout?

I've used the XStream serializer at xstream.codehaus.org Drop in the jar
file and you can get output as easy as
XStream xs = new XStream ();
System.out.println (xs.toXML (yourObject));

  I have written a dumper, which dumps to my custom format as the
  following example shows:

class Ship
{ Ship ship;
  final java.lang.String a0 = "abc";
  final java.lang.String a1 = "abc";
  final java.lang.String a2 = new java.lang.String( a1 ); }

public class Main
{ public static void main( final java.lang.String[] args )
  { Ship ship = new Ship(); ship.ship = ship; // add self reference
    java.lang.System.out.println
    ( new de.dclj.ram.notation.junobjects.Junobjects().dump( ship )); }}

< &objectmap
  object =
  < &Ship
    a0 =
    < &java.lang.String zz0 >
    a1 =
    < &java.lang.String zz0 >
    a2 =
    < &java.lang.String zz1 >
    ship =
    < &Ship object >>
  zz0 =
  < &java.lang.String
    count =
    < &int 3 >
    hash =
    < &int 0 >
    offset =
    < &int 0 >
    value =
    < &[char[]] a b c >>
  zz1 =
  < &java.lang.String
    count =
    < &int 3 >
    hash =
    < &int 0 >
    offset =
    < &int 0 >
    value =
    < &[char[]] a b c >>>

  The dumper is available as part of ram.jar:

http://www.purl.org/stefan_ram/pub/ram-jar

  XStream, however, has custom code to handle some special types
  of objects, like enums, which Junobjects is missing. The point
  is that the value of an enum is not a field of that enum. So,
  while Junobjects dumps all the fields, sometimes this is not
  what might be wanted.

  Another means with only Jave SE is the inbuilt XML Beans encoder:

public class ExampleBean
{ private java.util.Map data;
  public ExampleBean(){ data = null; }
  public ExampleBean( final java.util.Map value ){ this.data = value; }
  public java.util.Map getProperty(){ return data; }
  public void setProperty( final java.util.Map value ){ this.data = value; }}

public class Main
{ public static void main( final java.lang.String[] _ )
  { final ExampleBean a = new ExampleBean();
    java.util.Map map = new java.util.HashMap();
    map.put( "alpha", new java.lang.String[][]{{ "1", "2" },{ "a" }} );
    map.put( new java.lang.Integer( 0 ), new java.lang.Double( 1 ));
    a.setProperty( map );
    final java.beans.XMLEncoder output = new java.beans.XMLEncoder
    ( new java.io.BufferedOutputStream
      ( new java.io.FileOutputStream( java.io.FileDescriptor.out )));
    try{ output.writeObject( a ); }
    finally{ output.close(); }}}

<?xml version="1.0" encoding="UTF-8"?>
<java version="1.6.0" class="java.beans.XMLDecoder">
<object class="ExampleBean">
  <void property="property">
   <object class="java.util.HashMap">
    <void method="put">
     <int>0</int>
     <double>1.0</double>
    </void>
    <void method="put">
     <string>alpha</string>
     <array class="[Ljava.lang.String;" length="2">
      <void index="0">
       <array class="java.lang.String" length="2">
        <void index="0">
         <string>1</string>
        </void>
        <void index="1">
         <string>2</string>
        </void>
       </array>
      </void>
      <void index="1">
       <array class="java.lang.String" length="1">
        <void index="0">
         <string>a</string>
        </void>
       </array>
      </void>
     </array>
    </void>
   </object>
  </void>
</object>
</java>

  However, one needs to get used to the behavior of the beans
  encoder, too. For example, it will omit fields if they
  have their default value as given by the required default
  constructor.