Package org.apache.beam.sdk.transforms.display

Interface DisplayData.Builder

  • Enclosing class:
    DisplayData
    public static interface DisplayData.Builder
    Utility to build up display data from a component and its included subcomponents.

    • Method Detail

      • include

        DisplayData.Builder include​(java.lang.String path,
                            HasDisplayData subComponent)
        Register display data from the specified subcomponent at the given path. For example, a PTransform which delegates to a user-provided function can implement HasDisplayData on the function and include it from the PTransform: 
        @Override
 public void populateDisplayData(DisplayData.Builder builder) {
   super.populateDisplayData(builder);

   builder
     // To register the class name of the userFn
     .add(DisplayData.item("userFn", userFn.getClass()))
     // To allow the userFn to register additional display data
     .include("userFn", userFn);
 }

        Using include(path, subComponent) will associate each of the registered items with the namespace of the subComponent being registered, with the specified path element relative to the current path. To register display data in the current path and namespace, such as from a base class implementation, use subComponent.populateDisplayData(builder) instead.

        See Also:
        HasDisplayData.populateDisplayData(DisplayData.Builder)

      • delegate

        DisplayData.Builder delegate​(HasDisplayData component)
        Register display data from the specified component on behalf of the current component. Display data items will be added with the subcomponent namespace but the current component path.

        This is useful for components which simply wrap other components and wish to retain the display data from the wrapped component. Such components should implement populateDisplayData as: 

        @Override
 public void populateDisplayData(DisplayData.Builder builder) {
   builder.delegate(wrapped);
 }

      • addIfNotDefault

        <T> DisplayData.Builder addIfNotDefault​(DisplayData.ItemSpec<T> item,
                                        @Nullable T defaultValue)
        Register the given display item if the value is different than the specified default.