how to store TimeStamp into db4o database

Question

I am trying to store timestamps into a db4o database, but the stored timestamps which store a few mninutes ago are much different from the current date.

Here are example outputs:

1969-12-31 19:00:00.741
1969-12-31 19:00:00.772
2012-10-14 00:23:22.713

The two previous stored timestamp was stored as 1969-12-31 19:00:00.7xx after I run my code three times.

Here is the code.

import java.sql.Timestamp;

import com.db4o.Db4oEmbedded;
import com.db4o.ObjectContainer;
import com.db4o.ObjectSet;
import com.db4o.config.EmbeddedConfiguration;

public class dbTest {

  public static void listResults(ObjectSet<Timestamp> results) {

    for (Timestamp o : results) {
      System.out.println(o);
    }
  }

  public static void main(String[] args) {

    EmbeddedConfiguration config = Db4oEmbedded.newConfiguration();
    config.common().objectClass(Timestamp.class).storeTransientFields(true);

    ObjectContainer container = Db4oEmbedded
        .openFile(config, "timestamps.db4o");

    try {

      long now = System.currentTimeMillis();
      container.store(new Timestamp(now));

      final ObjectSet<Timestamp> results = container.query(Timestamp.class);
      listResults(results);
    }
    finally {
      container.close();
    }
  }
}

I read the two pieces of related article below but the issue has not been solved.

article 1 and article 2

Please advise me how to solve this issue. Thanks.

Answer 1

The solution to this problem by adding a line:

config.common().objectClass(Timestamp.class).translate(new TSerializable());

I got help from Vidisha & Claude at db4o forum. Here I share the answer, and hope to help other as well. Here is the new code.

import java.sql.Timestamp;   

import com.db4o.Db4oEmbedded;   
import com.db4o.ObjectContainer;   
import com.db4o.ObjectSet;   
import com.db4o.config.EmbeddedConfiguration;   

public class dbTest {   

  public static void listResults(ObjectSet<Timestamp> results) {   

    for (Timestamp o : results) {   
      System.out.println(o);   
    }   
  }   

  public static void main(String[] args) {   

    EmbeddedConfiguration config = Db4oEmbedded.newConfiguration();   
    config.common().objectClass(Timestamp.class).translate(new TSerializable());   
    ObjectContainer container = Db4oEmbedded   
        .openFile(config, "timestamps.db4o");   

    try {   

      long now = System.currentTimeMillis();   
      container.store(new Timestamp(now));   

      final ObjectSet<Timestamp> results = container.query(Timestamp.class);   
      listResults(results);   
    }   
    finally {   
      container.close();   
    }   
  }   
}   

You are recommanded to use JDK Date which can be handled properly by db4o.