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 Summary

Modifier and Type	Method and Description
DisplayData.Builder	add(DisplayData.ItemSpec<?> item) Register the given display item.
<T> DisplayData.Builder	addIfNotDefault(DisplayData.ItemSpec<T> item, T defaultValue) Register the given display item if the value is different than the specified default.
DisplayData.Builder	addIfNotNull(DisplayData.ItemSpec<?> item) Register the given display item if the value is not null.
DisplayData.Builder	delegate(HasDisplayData component) Register display data from the specified component on behalf of the current component.
DisplayData.Builder	include(java.lang.String path, HasDisplayData subComponent) Register display data from the specified subcomponent at the given path.

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);
 }
 

add

DisplayData.Builder add(DisplayData.ItemSpec<?> item)

Register the given display item.

addIfNotNull

DisplayData.Builder addIfNotNull(DisplayData.ItemSpec<?> item)

Register the given display item if the value is not null.

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.