co.cask.cdap.etl.api

Interface StageContext

All Known Subinterfaces:

ActionContext, BatchActionContext, BatchAggregatorContext, BatchContext, BatchJoinerContext, BatchJoinerRuntimeContext, BatchRuntimeContext, BatchSinkContext, BatchSourceContext, RealtimeContext, TransformContext

@Beta
public interface StageContext

Context for a pipeline stage, providing access to information about the stage, metrics, and plugins.

Method Summary

Methods

Modifier and Type	Method and Description
StageMetrics	getMetrics() Get an instance of StageMetrics, used to collect metrics for this stage.
PluginProperties	getPluginProperties() Gets the PluginProperties associated with the stage.
PluginProperties	getPluginProperties(String pluginId) Gets the PluginProperties associated with the given plugin id.
String	getStageName() Gets the unique stage name of the transform, useful for setting the context of logging in transforms.
<T> Class<T>	loadPluginClass(String pluginId) Loads and returns a plugin class as specified by the given plugin id.
<T> T	newPluginInstance(String pluginId) Creates a new instance of a plugin.

Method Detail

getStageName

String getStageName()

Gets the unique stage name of the transform, useful for setting the context of logging in transforms.

Returns:

stage name

getMetrics

StageMetrics getMetrics()

Get an instance of StageMetrics, used to collect metrics for this stage. Metrics emitted from one stage are independent from metrics emitted in another.

Returns:

StageMetrics for collecting metrics

getPluginProperties

PluginProperties getPluginProperties()

Gets the PluginProperties associated with the stage.

Returns:

the PluginProperties.

getPluginProperties

PluginProperties getPluginProperties(String pluginId)

Gets the PluginProperties associated with the given plugin id.

Parameters:

pluginId - the unique identifier provide when declaring plugin usage in the program.

Returns:

the PluginProperties.

Throws:

IllegalArgumentException - if pluginId is not found

UnsupportedOperationException - if the program does not support plugin

loadPluginClass

<T> Class<T> loadPluginClass(String pluginId)

Loads and returns a plugin class as specified by the given plugin id.

Type Parameters:

T - the class type of the plugin

Parameters:

pluginId - the unique identifier provide when declaring plugin usage in the program.

Returns:

the resulting plugin Class.

Throws:

IllegalArgumentException - if pluginId is not found

UnsupportedOperationException - if the program does not support plugin

newPluginInstance

<T> T newPluginInstance(String pluginId)
                    throws InstantiationException

Creates a new instance of a plugin. The instance returned will have the PluginConfig setup with PluginProperties provided at the time when the PluginConfigurer.usePlugin(String, String, String, PluginProperties) was called during the program configuration time.

Type Parameters:

T - the class type of the plugin

Parameters:

pluginId - the unique identifier provide when declaring plugin usage in the program.

Returns:

A new instance of the plugin being specified by the arguments

Throws:

InstantiationException - if failed create a new instance

IllegalArgumentException - if pluginId is not found

UnsupportedOperationException - if the program does not support plugin