Using the IPdxSerializable Interface

When you write objects using PDX serialization, they are distributed to the server tier in PDX serialized form. When you run queries against the objects on the servers, only the fields you specify are deserialized.

Use this procedure to program your domain object for PDX serialization using the IPdxSerializable Interface.

1. In your domain class, implement Apache.Geode.Client.IPdxSerializable. Example:

   using Apache.Geode.Client;
          ...
          public class PortfolioPdx : IPdxSerializable
   

2. If your domain class does not have a zero-arg constructor, create one for it.

   If you also use PDX serialization in Java for the object, serialize the object in the same way for each language. Serialize the same fields in the same order and mark the same identify fields.

3. Program the IPdxSerializable ToData function to serialize your object as required by your application.

   1. Write your domain class’s standard .NET Framework data fields using the IPdxWriter write methods. GemFire automatically provides IPdxWriter to the ToData function for IPdxSerializable objects.

   2. Call the ToData MarkIdentifyField function for each field GemFire should use to identify your object. This is used to compare objects for operations like DISTINCT queries. The MarkIdentifyField call must come after the associated field write methods.

      Example:

      // object fields
      private int m_id;
      private string m_pkid;
      private PositionPdx m_position1;
      private PositionPdx m_position2;
      private Hashtable m_positions;
      private string m_type;
      private string m_status;
      private string[] m_names;
      private byte[] m_newVal;
      private DateTime m_creationDate;
      private byte[] m_arrayZeroSize;
      private byte[] m_arrayNull;
      // ToData
      public void ToData(IPdxWriter writer)
      {
         writer.WriteInt("id", m_id)
         //identity field
            .MarkIdentityField("id")
            .WriteString("pkid", m_pkid)
            .WriteObject("position1", m_position1)
            .WriteObject("position2", m_position2)
      .WriteObject("positions", m_positions)
      .WriteString("type", m_type)
      .WriteString("status", m_status)
      .WriteStringArray("names", m_names)
      .WriteByteArray("newVal", m_newVal)
      .WriteDate("creationDate", m_creationDate)
      .WriteByteArray("arrayNull", m_arrayNull)
      .WriteByteArray("arrayZeroSize", m_arrayZeroSize);
      }
      

4. Program IPdxSerializable FromData to read your data fields from the serialized form into the object’s fields using the IPdxReader read methods. GemFire automatically provides IPdxReader to the FromData function for IPdxSerializable objects.

   Use the same names as you did in ToData and call the read operations in the same order as you called the write operations in your ToData implementation.

   Example:

   public void FromData(IPdxReader reader)
      {
         m_id = reader.ReadInt("id");
   
         bool isIdentity = reader.IsIdentityField("id");
   
         if (isIdentity == false)
            throw new IllegalStateException("Portfolio id is identity field");
   
         bool isId = reader.HasField("id");
   
         if (isId == false)
            throw new IllegalStateException("Portfolio id field not found");
   
         bool isNotId = reader.HasField("ID");
   
         if (isNotId == true)
            throw new IllegalStateException("Portfolio isNotId field found");
   
         m_pkid = reader.ReadString("pkid");
         m_position1 = (PositionPdx)reader.ReadObject("position1");
         m_position2 = (PositionPdx)reader.ReadObject("position2");
         m_positions = (Hashtable)reader.ReadObject("positions");
         m_type = reader.ReadString("type");
         m_status = reader.ReadString("status");
         m_names = reader.ReadStringArray("names");
         m_newVal = reader.ReadByteArray("newVal");
         m_creationDate = reader.ReadDate("creationDate");
         m_arrayNull = reader.ReadByteArray("arrayNull");
         m_arrayZeroSize = reader.ReadByteArray("arrayZeroSize");
   }
   

5. Optionally, program your domain object’s Equals and Hashcode methods.