CustomCoder (Google Cloud Dataflow SDK 1.9.1 API)

Google Cloud Dataflow SDK for Java, version 1.9.1

Warning: Dataflow SDK 1.x for Java is unsupported as of October 16, 2018. See Migrating from Dataflow SDK 1.x for Java for migration guidance.

Note: If you are using Cloud Dataflow SDK version 2.x, see the Apache Beam API reference documentation.

com.google.cloud.dataflow.sdk.coders

Class CustomCoder<T>

• java.lang.Object
• • com.google.cloud.dataflow.sdk.coders.StandardCoder<T>
  • • com.google.cloud.dataflow.sdk.coders.DeterministicStandardCoder<T>
    • • com.google.cloud.dataflow.sdk.coders.AtomicCoder<T>
      • • com.google.cloud.dataflow.sdk.coders.CustomCoder<T>

• Type Parameters:

  T - the type of elements handled by this coder

  All Implemented Interfaces:

  Coder<T>, Serializable

  Direct Known Subclasses:

  DelegateCoder

  ---

  
  

  public abstract class CustomCoder<T>
  extends AtomicCoder<T>
  implements Serializable

  An abstract base class for writing a Coder class that encodes itself via Java serialization.

  To complete an implementation, subclasses must implement Coder.encode(T, java.io.OutputStream, com.google.cloud.dataflow.sdk.coders.Coder.Context) and Coder.decode(java.io.InputStream, com.google.cloud.dataflow.sdk.coders.Coder.Context) methods. Anonymous subclasses must furthermore override getEncodingId().

  Not to be confused with SerializableCoder that encodes objects that implement the Serializable interface.

  See Also:

  Serialized Form

• • Nested Class Summary

    • Nested classes/interfaces inherited from interface com.google.cloud.dataflow.sdk.coders.Coder

      Coder.Context, Coder.NonDeterministicException

  • Constructor Summary

    Constructors 

    Constructor and Description
    CustomCoder()

  • Method Summary

    All Methods Static Methods Instance Methods Concrete Methods 

    Modifier and Type	Method and Description
    com.google.cloud.dataflow.sdk.util.CloudObject	asCloudObject() Returns the CloudObject that represents this Coder.
    String	getEncodingId() An identifier for the binary format written by Coder.encode(T, java.io.OutputStream, com.google.cloud.dataflow.sdk.coders.Coder.Context).
    static CustomCoder<?>	of(String typeId, String encodingId, String type, String serializedCoder)
    void	verifyDeterministic() Throw Coder.NonDeterministicException if the coding is not deterministic.

    • Methods inherited from class com.google.cloud.dataflow.sdk.coders.AtomicCoder

      getCoderArguments, getInstanceComponents

    • Methods inherited from class com.google.cloud.dataflow.sdk.coders.StandardCoder

      consistentWithEquals, equals, getAllowedEncodings, getComponents, getEncodedElementByteSize, hashCode, isRegisterByteSizeObserverCheap, registerByteSizeObserver, structuralValue, toString, verifyDeterministic, verifyDeterministic

    • Methods inherited from class java.lang.Object

      clone, finalize, getClass, notify, notifyAll, wait, wait, wait

    • Methods inherited from interface com.google.cloud.dataflow.sdk.coders.Coder

      decode, encode

• • Constructor Detail

    • CustomCoder

      public CustomCoder()

  • Method Detail

    • of

      public static CustomCoder<?> of(String typeId,
                                      String encodingId,
                                      String type,
                                      String serializedCoder)

    • asCloudObject

      public com.google.cloud.dataflow.sdk.util.CloudObject asCloudObject()

      Returns the CloudObject that represents this Coder.

      Specified by:

      asCloudObject in interface Coder<T>

      Overrides:

      asCloudObject in class StandardCoder<T>

      Returns:

      A thin CloudObject wrapping of the Java serialization of this.

    • verifyDeterministic

      public void verifyDeterministic()
                               throws Coder.NonDeterministicException

      Throw Coder.NonDeterministicException if the coding is not deterministic.

      In order for a Coder to be considered deterministic, the following must be true:

      • two values that compare as equal (via Object.equals() or Comparable.compareTo(), if supported) have the same encoding.
      • the Coder always produces a canonical encoding, which is the same for an instance of an object even if produced on different computers at different times.

      Specified by:

      verifyDeterministic in interface Coder<T>

      Overrides:

      verifyDeterministic in class DeterministicStandardCoder<T>

      Throws:

      NonDeterministicException - a CustomCoder is presumed nondeterministic.

      Coder.NonDeterministicException - if this coder is not deterministic.

    • getEncodingId

      public String getEncodingId()

      An identifier for the binary format written by Coder.encode(T, java.io.OutputStream, com.google.cloud.dataflow.sdk.coders.Coder.Context).

      This value, along with the fully qualified class name, forms an identifier for the binary format of this coder. Whenever this value changes, the new encoding is considered incompatible with the prior format: It is presumed that the prior version of the coder will be unable to correctly read the new format and the new version of the coder will be unable to correctly read the old format.

      If the format is changed in a backwards-compatible way (the Coder can still accept data from the prior format), such as by adding optional fields to a Protocol Buffer or Avro definition, and you want Dataflow to understand that the new coder is compatible with the prior coder, this value must remain unchanged. It is then the responsibility of Coder.decode(java.io.InputStream, com.google.cloud.dataflow.sdk.coders.Coder.Context) to correctly read data from the prior format.

      Specified by:

      getEncodingId in interface Coder<T>

      Overrides:

      getEncodingId in class StandardCoder<T>

      Returns:

      The canonical class name for this coder. For stable data formats that are independent of class name, it is recommended to override this method.

      Throws:

      UnsupportedOperationException - when an anonymous class is used, since they do not have a stable canonical class name.