Operator Serializer

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The Serlizer operator serializes input tuples in network byte order and emits tuples with an attribute of a blob or rstring to the output port.

All attributes of the input tuple are serialized by default. To control which attributes are serialized and emitted, use the inputAttributes parameter.

Beyond the attribute values, the serialization result emitted may include type information at the beginning of the payload to validate transmission configuration on the receiver side. By default, every 100th tuple emitted contains type information in the payload. The type information can be included in every payload by setting the activateTypeList parameter to true. Otherwise, the iterateTypeListCount parameter can be used to control how frequent the type information is present.

Examples 


use com.teracloud.streams.inet.util::*;
public composite Main {
  graph
    stream<rstring firstName, rstring lastName, uint8 age> Input = Beacon() {}

    // Serialize all input tuples
    stream<blob binaryData> AllStream = Serializer(Input) {
      output AllSerializedStream:
        binaryData = serialized();
    }

    // Serialize select tuples and include type info in every payload
    stream<uint64 sequence, blob binaryData> SelectStream = Serializer(Input) {
      param
        inputAttributes: firstName, age;
        activateTypeList: true;
      output SelectStream:
        sequence = sequence();
        binaryData = serialized();
    }
}

Summary

Ports
This operator has 1 input port and 1 output port.
Windowing
This operator does not accept any windowing configurations.
Parameters
This operator supports 3 parameters.

Optional: activateTypeList, inputAttributes, iterateTypeListCount

Metrics
This operator does not report any metrics.

Properties

Implementation
C++
Threading
Always - Operator always provides a single threaded execution context.

Input Ports

Ports (0)

The tuples of this single input port are serialized and the serialization result is emitted as a blob to the output port.

Properties

Output Ports

Assignments
This operator allows any SPL expression of the correct type to be assigned to output attributes. Attributes not assigned in the output clause will be automatically assigned from the attributes of the input ports that have the same name and type. If there is no such input attribute, an error is reported at compile-time.
Output Functions
SerializeFunctions
<any T> T AsIs(T)

The default function for output attributes. This function assigns the output attribute to the value of the input attribute with the same name.

<any T> T serialized()

Get the serialized data payload. The output attribute type must be rstring or blob.

uint64 sequence()

Sequence number of the output tuple. Starts with zero. Must be of type uint64.

Ports (0)

The output port with the serialized data. With output function serialized the serialized data can be assigned to output attributes. With output function sequence the sequence number can be assigned to an attribute. All other attributes are assigned from input tuple.

Properties

Parameters

This operator supports 3 parameters.

Optional: activateTypeList, inputAttributes, iterateTypeListCount

activateTypeList

If this parameter is true, a type list information is inserted into the serialized data block. Default is false.

Properties

inputAttributes

This parameter specifies the attributes of the input stream to serialize. If this parameter is absent, all input attributes will be included in the serialized output blob/rstring.

Note: The serialization sequence of the input attributes corresponds to the sequence of this parameter. If this parameter is absent, the attribute sequence of the input tuple is significant.

Properties

iterateTypeListCount

This parameter controls how often the type list information is embedded in the serialization data block. The operator inserts type information every iterateTypeListCount tuple. If the value is zero, no type list information is inserted. Default is 100.

Properties

Code Templates

Serializer

stream<${schema}> ${outputStream} = com.teracloud.streams.inet.util::Serializer(${inputStream}) {
  param
      ${parameter}: ${parameterExpression};
  output
      ${outputStream}: ${outputAttribute} = ${value};
}