Package io.github.kaststream.api.v2.facade

Interface KastRuntimeContext

public interface KastRuntimeContext

Method Summary

Modifier and Type	Method	Description
int	getAttemptNumber()	Gets the attempt number of this parallel subtask.
int	getIndexOfThisSubtask()	Gets the number of this parallel subtask.
String	getJobId()	The ID of the current job.
<UK,UV> KastMapState<UK,UV>	getMapState(String name, Class<UK> keyClass, Class<UV> valueClass)	Gets a handle to the system's key/value map state.
int	getMaxNumberOfParallelSubtasks()	Gets the number of max-parallelism with which the parallel task runs.
int	getNumberOfParallelSubtasks()	Gets the parallelism with which the parallel task runs.
String	getTaskName()	Returns the name of the task in which the UDF runs, as assigned during plan construction.
String	getTaskNameWithSubtasks()	Returns the name of the task, appended with the subtask indicator, such as "MyTask (3/6)#1", where 3 would be (getIndexOfThisSubtask() + 1), and 6 would be getNumberOfParallelSubtasks(), and 1 would be getAttemptNumber().
ClassLoader	getUserCodeClassLoader()	Gets the ClassLoader to load classes that are not in system's classpath, but are part of the jar file of a user job.
boolean	hasBroadcastVariable(String name)	Tests for the existence of the broadcast variable identified by the given name.

Method Detail

getJobId

String getJobId()

The ID of the current job. Note that Job ID can change in particular upon manual restart. The returned ID should NOT be used for any job management tasks.

getTaskName

String getTaskName()

Returns the name of the task in which the UDF runs, as assigned during plan construction.

Returns:

The name of the task in which the UDF runs.

getNumberOfParallelSubtasks

int getNumberOfParallelSubtasks()

Gets the parallelism with which the parallel task runs.

Returns:

The parallelism with which the parallel task runs.

getMaxNumberOfParallelSubtasks

int getMaxNumberOfParallelSubtasks()

Gets the number of max-parallelism with which the parallel task runs.

Returns:

The max-parallelism with which the parallel task runs.

getIndexOfThisSubtask

int getIndexOfThisSubtask()

Gets the number of this parallel subtask. The numbering starts from 0 and goes up to parallelism-1 (parallelism as returned by getNumberOfParallelSubtasks()).

Returns:

The index of the parallel subtask.

getAttemptNumber

int getAttemptNumber()

Gets the attempt number of this parallel subtask. First attempt is numbered 0.

Returns:

Attempt number of the subtask.

getTaskNameWithSubtasks

String getTaskNameWithSubtasks()

Returns the name of the task, appended with the subtask indicator, such as "MyTask (3/6)#1", where 3 would be (getIndexOfThisSubtask() + 1), and 6 would be getNumberOfParallelSubtasks(), and 1 would be getAttemptNumber().

Returns:

The name of the task, with subtask indicator.

getUserCodeClassLoader

ClassLoader getUserCodeClassLoader()

Gets the ClassLoader to load classes that are not in system's classpath, but are part of the jar file of a user job.

Returns:

The ClassLoader for user code classes.

hasBroadcastVariable

boolean hasBroadcastVariable(String name)

Tests for the existence of the broadcast variable identified by the given name.

Parameters:

name - The name under which the broadcast variable is registered;

Returns:

Whether a broadcast variable exists for the given name.

getMapState

<UK,UV> KastMapState<UK,UV> getMapState(String name,
                                                    Class<UK> keyClass,
                                                    Class<UV> valueClass)

Gets a handle to the system's key/value map state.

This state is only accessible if the function is executed on a KeyedStream.

 DataStream<MyType> stream = ...;
 KeyedStream<MyType> keyedStream = stream.keyBy("id");

 keyedStream.map(new RichMapFunction<MyType, List<MyType>>() {

     private MapState<MyType, Long> state;

     public void open(Configuration cfg) {
         state = getRuntimeContext().getMapState(
                 new MapStateDescriptor<>("sum", MyType.class, Long.class));
     }

     public Tuple2<MyType, Long> map(MyType value) {
         return new Tuple2<>(value, state.get(value));
     }
 });

 

Type Parameters:

UK - The type of the user keys stored in the state.

UV - The type of the user values stored in the state.

Returns:

The partitioned state object.

Throws:

UnsupportedOperationException - Thrown, if no partitioned state is available for the function (function is not part of a KeyedStream).