Re: [Simple-support] can't serialize an object which uses aparametrized hashmap

[<Nia...@ub...>]

Hi,

This is because T does not exist. In java the generic type T used to
parameterize MyMap disappears after compilation. It's a process called
erasure and it means that the type can not be acquired reflectively at
runtime. There is talk of Java 7 resolving this issue but for Java 5 and
6 you will not be able to execute the code you have provided.

Niall 

-----Original Message-----
From: Joe [mailto:fis...@ya...] 
Sent: 01 April 2009 15:45
To: sim...@li...
Subject: [Simple-support] can't serialize an object which uses
aparametrized hashmap

Hi,

the following code throws an exception.
But if i replace T by String, serialization is no problem.

Why the parametrized version doesn't work?

Version: 2.0.4

import java.io.File;
import java.util.HashMap;

import org.simpleframework.xml.ElementMap;
import org.simpleframework.xml.Serializer;
import org.simpleframework.xml.core.Persister;

public class MyMap<T>
{
  @ElementMap
  private HashMap<T, String> map = new HashMap<T, String>();

  public static void main(String[] args)
  {
    try
    {
      serialize(new MyMap<String>());
      System.out.println("done");
    }
    catch (Exception e)
    {
      e.printStackTrace();
    }
  }

  private static void serialize(Object data) throws Exception
  {
    Serializer serializer = new Persister();
    File xmlFile = new File("test.xml");
    serializer.write(data, xmlFile);
  }
}


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