// Copyright (c) 2006- Facebook
// Distributed under the Thrift Software License
//
// See accompanying file LICENSE or visit the Thrift site at:
// http://developers.facebook.com/thrift/

package com.facebook.thrift;

import java.io.ByteArrayOutputStream;
import java.io.UnsupportedEncodingException;

import com.facebook.thrift.protocol.TBinaryProtocol;
import com.facebook.thrift.protocol.TProtocol;
import com.facebook.thrift.protocol.TProtocolFactory;
import com.facebook.thrift.transport.TIOStreamTransport;
import com.facebook.thrift.transport.TTransport;

/**
 * Generic utility for easily serializing objects into a byte array or Java
 * String.
 *
 * @author Mark Slee <mcslee@facebook.com>
 */
public class TSerializer {

  /**
   * This is the byte array that data is actually serialized into
   */
  private final ByteArrayOutputStream baos_ = new ByteArrayOutputStream();

  /**
   * This transport wraps that byte array
   */
  private final TIOStreamTransport transport_ = new TIOStreamTransport(baos_);

  /**
   * Internal protocol used for serializing objects.
   */
  private TProtocol protocol_;

  /**
   * Create a new TSerializer that uses the TBinaryProtocol by default.
   *
   * @param protocolFactory Factory to create a protocol
   */
  public TSerializer() {
    this(new TBinaryProtocol.Factory());
  }

  /**
   * Create a new TSerializer. It will use the TProtocol specified by the
   * factory that is passed in.
   *
   * @param protocolFactory Factory to create a protocol
   */
  public TSerializer(TProtocolFactory protocolFactory) {
    protocol_ = protocolFactory.getProtocol(transport_);
  }

  /**
   * Serialize the Thrift object into a byte array. The process is simple,
   * just clear the byte array output, write the object into it, and grab the
   * raw bytes.
   *
   * @param base The object to serialize
   * @return Serialized object in byte[] format
   */
  public byte[] serialize(TBase base) throws TException {
    baos_.reset();
    base.write(protocol_);
    return baos_.toByteArray();
  }

  /**
   * Serialize the Thrift object into a Java string, using a specified
   * character set for encoding.
   *
   * @param base The object to serialize
   * @param charset Valid JVM charset
   * @return Serialized object as a String
   */
  public String toString(TBase base, String charset) throws TException {
    try {
      return new String(serialize(base), charset);
    } catch (UnsupportedEncodingException uex) {
      throw new TException("JVM DOES NOT SUPPORT ENCODING: " + charset);
    }
  }

  /**
   * Serialize the Thrift object into a Java string, using the default JVM
   * charset encoding.
   *
   * @param base The object to serialize
   * @return Serialized object as a String
   */
  public String toString(TBase base) throws TException {
    return new String(serialize(base));
  }
}