CoderFactories (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 CoderFactories

• java.lang.Object
• • com.google.cloud.dataflow.sdk.coders.CoderFactories

• ---

  
  

  public final class CoderFactories
  extends Object

  Static utility methods for creating and working with Coders.

• • Method Summary

    All Methods Static Methods Concrete Methods 

    Modifier and Type	Method and Description
    static <T> CoderFactory	forCoder(Coder<T> coder) Creates a CoderFactory that always returns the given coder.
    static <T> CoderFactory	fromStaticMethods(Class<T> clazz) Creates a CoderFactory built from particular static methods of a class that implements Coder.

    • Methods inherited from class java.lang.Object

      clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

• • Method Detail

    • fromStaticMethods

      public static <T> CoderFactory fromStaticMethods(Class<T> clazz)

      Creates a CoderFactory built from particular static methods of a class that implements Coder.

      The class must have the following static methods:

      • public static Coder<T> of(Coder<X> argCoder1, Coder<Y> argCoder2, ...)
      • public static List<Object> getInstanceComponents(T exampleValue);

      The of(...) method will be used to construct a Coder<T> from component Coders. It must accept one Coder argument for each generic type parameter of T. If T takes no generic type parameters, then the of() factory method should take no arguments.

      The getInstanceComponents method will be used to decompose a value during the Coder inference process, to automatically choose coders for the components.

      Note that the class T to be coded may be a not-yet-specialized generic class. For a generic class MyClass<X> and an actual type parameter Foo, the CoderFactoryFromStaticMethods will accept any Coder<Foo> and produce a Coder<MyClass<Foo>>.

      For example, the CoderFactory returned by fromStaticMethods(ListCoder.class) will produce a Coder<List<X>> for any Coder Coder<X>.

    • forCoder

      public static <T> CoderFactory forCoder(Coder<T> coder)

      Creates a CoderFactory that always returns the given coder.

      The getInstanceComponents method of this CoderFactory always returns an empty list.