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

Class DisplayData

java.lang.Object

org.apache.beam.sdk.transforms.display.DisplayData

All Implemented Interfaces:

Serializable

public class DisplayData
extends Object
implements Serializable

Static display data associated with a pipeline component. Display data is useful for pipeline runner UIs and diagnostic dashboards to display details about PTransforms that make up a pipeline.

Components specify their display data by implementing the HasDisplayData interface.

See Also:

• Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	DisplayData.Builder	Utility to build up display data from a component and its included subcomponents.
static class	DisplayData.Identifier	Unique identifier for a display data item within a component.
static class	DisplayData.Item	Items are the unit of display data.
static class	DisplayData.ItemSpec<T>	Specifies an DisplayData.Item to register as display data.
static class	DisplayData.Path	Structured path of registered display data within a component hierarchy.
static enum	DisplayData.Type	Display data type.

Method Summary

Modifier and Type	Method	Description
Map<DisplayData.Identifier,DisplayData.Item>	asMap()
boolean	equals(@Nullable Object obj)
static DisplayData	from(HasDisplayData component)	Collect the DisplayData from a component.
int	hashCode()
static @Nullable DisplayData.Type	inferType(@Nullable Object value)	Infer the DisplayData.Type for the given object.
static DisplayData.ItemSpec<Boolean>	item(String key, @Nullable Boolean value)	Create a display item for the specified key and boolean value.
static <T> DisplayData.ItemSpec<Class<T>>	item(String key, @Nullable Class<T> value)	Create a display item for the specified key and class value.
static DisplayData.ItemSpec<Double>	item(String key, @Nullable Double value)	Create a display item for the specified key and floating point value.
static DisplayData.ItemSpec<Float>	item(String key, @Nullable Float value)	Create a display item for the specified key and floating point value.
static DisplayData.ItemSpec<Integer>	item(String key, @Nullable Integer value)	Create a display item for the specified key and integer value.
static DisplayData.ItemSpec<Long>	item(String key, @Nullable Long value)	Create a display item for the specified key and integer value.
static DisplayData.ItemSpec<String>	item(String key, @Nullable String value)	Create a display item for the specified key and string value.
static DisplayData.ItemSpec<?>	item(String key, @Nullable ValueProvider<?> value)	Create a display item for the specified key and ValueProvider.
static <T> DisplayData.ItemSpec<T>	item(String key, DisplayData.Type type, @Nullable T value)	Create a display item for the specified key, type, and value.
static DisplayData.ItemSpec<Duration>	item(String key, @Nullable Duration value)	Create a display item for the specified key and duration value.
static DisplayData.ItemSpec<Instant>	item(String key, @Nullable Instant value)	Create a display item for the specified key and timestamp value.
Collection<DisplayData.Item>	items()
static DisplayData	none()	Default empty DisplayData instance.
String	toString()

Methods inherited from class java.lang.Object

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

Method Details

none

public static DisplayData none()

Default empty DisplayData instance.

from

public static DisplayData from(HasDisplayData component)

Collect the DisplayData from a component. This will traverse all subcomponents specified via DisplayData.Builder.include(java.lang.String, org.apache.beam.sdk.transforms.display.HasDisplayData) in the given component. Data in this component will be in a namespace derived from the component.

inferType

public static @Nullable DisplayData.Type inferType(@Nullable Object value)

Infer the DisplayData.Type for the given object.

Use this method if the type of metadata is not known at compile time. For example:

@Override
 public void populateDisplayData(DisplayData.Builder builder) {
   Optional<DisplayData.Type> type = DisplayData.inferType(foo);
   if (type.isPresent()) {
     builder.add(DisplayData.item("foo", type.get(), foo));
   }
 }
 

Returns:

The inferred DisplayData.Type, or null if the type cannot be inferred,

items

public Collection<DisplayData.Item> items()

asMap

public Map<DisplayData.Identifier,DisplayData.Item> asMap()

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(@Nullable Object obj)

Overrides:

equals in class Object

toString

public String toString()

Overrides:

toString in class Object

item

public static DisplayData.ItemSpec<String> item(String key,
 @Nullable String value)

Create a display item for the specified key and string value.

item

public static DisplayData.ItemSpec<?> item(String key,
 @Nullable ValueProvider<?> value)

Create a display item for the specified key and ValueProvider.

item

public static DisplayData.ItemSpec<Integer> item(String key,
 @Nullable Integer value)

Create a display item for the specified key and integer value.

item

public static DisplayData.ItemSpec<Long> item(String key,
 @Nullable Long value)

Create a display item for the specified key and integer value.

item

public static DisplayData.ItemSpec<Float> item(String key,
 @Nullable Float value)

Create a display item for the specified key and floating point value.

item

public static DisplayData.ItemSpec<Double> item(String key,
 @Nullable Double value)

Create a display item for the specified key and floating point value.

item

public static DisplayData.ItemSpec<Boolean> item(String key,
 @Nullable Boolean value)

Create a display item for the specified key and boolean value.

item

public static DisplayData.ItemSpec<Instant> item(String key,
 @Nullable Instant value)

Create a display item for the specified key and timestamp value.

item

public static DisplayData.ItemSpec<Duration> item(String key,
 @Nullable Duration value)

Create a display item for the specified key and duration value.

item

public static <T> DisplayData.ItemSpec<Class<T>> item(String key,
 @Nullable Class<T> value)

Create a display item for the specified key and class value.

item

public static <T> DisplayData.ItemSpec<T> item(String key,
 DisplayData.Type type,
 @Nullable T value)

Create a display item for the specified key, type, and value. This method should be used if the type of the input value can only be determined at runtime. Otherwise, HasDisplayData implementors should call one of the typed factory methods, such as item(String, String) or item(String, Integer).

Throws:

ClassCastException - if the value cannot be formatted as the given type.

See Also:

• inferType(Object)