@Override
  public boolean equals(Object obj) {
    if (this == obj)
      return true;
    if (obj == null)
      return false;
    if (getClass() != obj.getClass())
      return false;
    SystemStream other = (SystemStream) obj;
    if (stream == null) {
      if (other.stream != null)
        return false;
    } else if (!stream.equals(other.stream))
      return false;
    if (system == null) {
      if (other.system != null)
        return false;
    } else if (!system.equals(other.system))
      return false;
    return true;
  }
Constructs a Samza stream object based upon an existing Samza stream.
@param other Reference to an already existing Samza stream.
samza-api/src/main/java/org/apache/samza/system/SystemStream.java