org.apache.beam.sdk.transforms.display

Class DisplayData.Item<T>

java.lang.Object

org.apache.beam.sdk.transforms.display.DisplayData.Item<T>

All Implemented Interfaces:

Serializable

Enclosing class:

DisplayData

public abstract static class DisplayData.Item<T>
extends Object
implements Serializable

Items are the unit of display data. Each item is identified by a given key and namespace from the component the display item belongs to.

Items are registered via DisplayData.Builder.add(org.apache.beam.sdk.transforms.display.DisplayData.Item<?>) within HasDisplayData.populateDisplayData(org.apache.beam.sdk.transforms.display.DisplayData.Builder) implementations.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
Item()

Method Summary

Modifier and Type	Method and Description
abstract String	getKey() The key for the display item.
abstract String	getLabel() Retrieve the optional label for an item.
abstract String	getLinkUrl() Retrieve the optional link URL for an item.
abstract String	getNamespace() The namespace for the display item.
abstract Object	getShortValue() Return the optional short value for an item, or null if none is provided.
abstract DisplayData.Type	getType() Retrieve the DisplayData.Type of display data.
abstract Object	getValue() Retrieve the value of the display item.
String	toString()
DisplayData.Item<T>	withLabel(String label) Set the item label.
DisplayData.Item<T>	withLinkUrl(String url) Set the item link url.
DisplayData.Item<T>	withNamespace(Class<?> namespace) Set the item namespace from the given Class.
DisplayData.Item<T>	withNamespace(String namespace)

Methods inherited from class java.lang.Object

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

Constructor Detail

Item

public Item()

Method Detail

getNamespace

@Nullable
public abstract String getNamespace()

The namespace for the display item. The namespace defaults to the component which the display item belongs to.

getKey

public abstract String getKey()

The key for the display item. Each display item is created with a key and value via {@link DisplayData#item).

getType

public abstract DisplayData.Type getType()

Retrieve the DisplayData.Type of display data. All metadata conforms to a predefined set of allowed types.

getValue

@Nullable
public abstract Object getValue()

Retrieve the value of the display item. The value is translated from the input to DisplayData.item(java.lang.String, java.lang.String) into a format suitable for display. Translation is based on the item's type.

The value will only be null if the input value during creation was null.

getShortValue

@Nullable
public abstract Object getShortValue()

Return the optional short value for an item, or null if none is provided.

The short value is an alternative display representation for items having a long display value. For example, the value for DisplayData.Type.JAVA_CLASS items contains the full class name with package, while the short value contains just the class name. A value will be provided for each display item, and some types may also provide a short-value. If a short value is provided, display data consumers may choose to display it instead of or in addition to the value.

getLabel

@Nullable
public abstract String getLabel()

Retrieve the optional label for an item. The label is a human-readable description of what the metadata represents. UIs may choose to display the label instead of the item key.

If no label was specified, this will return null.

getLinkUrl

@Nullable
public abstract String getLinkUrl()

Retrieve the optional link URL for an item. The URL points to an address where the reader can find additional context for the display data.

If no URL was specified, this will return null.

withNamespace

public DisplayData.Item<T> withNamespace(Class<?> namespace)

Set the item namespace from the given Class.

This method does not alter the current instance, but instead returns a new DisplayData.Item with the namespace set.

withNamespace

public DisplayData.Item<T> withNamespace(String namespace)

See Also:

withNamespace(Class)

withLabel

public DisplayData.Item<T> withLabel(String label)

Set the item label.

Specifying a null value will clear the label if it was previously defined.

This method does not alter the current instance, but instead returns a new DisplayData.Item with the label set.

withLinkUrl

public DisplayData.Item<T> withLinkUrl(String url)

Set the item link url.

Specifying a null value will clear the link url if it was previously defined.

This method does not alter the current instance, but instead returns a new DisplayData.Item with the link url set.

toString

public String toString()

Overrides:

toString in class Object