All Superinterfaces:

Function, Serializable

All Known Implementing Classes:

AbstractRichFunction, BulkIterationBase.TerminationCriterionMapper, NoOpFunction, RichAggregateFunction, RichCoGroupFunction, RichCrossFunction, RichFilterFunction, RichFlatJoinFunction, RichFlatMapFunction, RichGroupCombineFunction, RichGroupReduceFunction, RichJoinFunction, RichMapFunction, RichMapPartitionFunction, RichReduceFunction
```
@Public
public interface RichFunction
extends Function
```
An base interface for all rich user-defined functions. This class defines methods for the life cycle of the functions, as well as methods to access the context in which the functions are executed.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`close()`	Tear-down method for the user code.
`IterationRuntimeContext`	`getIterationRuntimeContext()`	Gets a specialized version of the `RuntimeContext`, which has additional information about the iteration in which the function is executed.
`RuntimeContext`	`getRuntimeContext()`	Gets the context that contains information about the UDF's runtime, such as the parallelism of the function, the subtask index of the function, or the name of the task that executes the function.
`void`	`open(Configuration parameters)`	Initialization method for the function.
`void`	`setRuntimeContext(RuntimeContext t)`	Sets the function's runtime context.

- Method Detail
  - open
```
void open(Configuration parameters)
   throws Exception
```
    Initialization method for the function. It is called before the actual working methods (like map or join) and thus suitable for one time setup work. For functions that are part of an iteration, this method will be invoked at the beginning of each iteration superstep.
    The configuration object passed to the function can be used for configuration and initialization. The configuration contains all parameters that were configured on the function in the program composition.
    public class MyFilter extends RichFilterFunction<String> { private String searchString; public void open(Configuration parameters) { this.searchString = parameters.getString("foo"); } public boolean filter(String value) { return value.equals(searchString); } }
    
    By default, this method does nothing.
    Parameters:
    
    parameters - The configuration containing the parameters attached to the contract.
    
    Throws:
    
    Exception - Implementations may forward exceptions, which are caught by the runtime. When the runtime catches an exception, it aborts the task and lets the fail-over logic decide whether to retry the task execution.
    
    See Also:
    
    Configuration
  - close
```
void close()
    throws Exception
```
    Tear-down method for the user code. It is called after the last call to the main working methods (e.g. map or join). For functions that are part of an iteration, this method will be invoked after each iteration superstep.
    This method can be used for clean up work.
    
    Throws:
    
    Exception - Implementations may forward exceptions, which are caught by the runtime. When the runtime catches an exception, it aborts the task and lets the fail-over logic decide whether to retry the task execution.
  - getRuntimeContext
```
RuntimeContext getRuntimeContext()
```
    Gets the context that contains information about the UDF's runtime, such as the parallelism of the function, the subtask index of the function, or the name of the task that executes the function.
    The RuntimeContext also gives access to the Accumulators and the DistributedCache.
    
    Returns:
    
    The UDF's runtime context.
  - getIterationRuntimeContext
```
IterationRuntimeContext getIterationRuntimeContext()
```
    Gets a specialized version of the RuntimeContext, which has additional information about the iteration in which the function is executed. This IterationRuntimeContext is only available if the function is part of an iteration. Otherwise, this method throws an exception.
    
    Returns:
    
    The IterationRuntimeContext.
    
    Throws:
    
    IllegalStateException - Thrown, if the function is not executed as part of an iteration.
  - setRuntimeContext
```
void setRuntimeContext(RuntimeContext t)
```
    Sets the function's runtime context. Called by the framework when creating a parallel instance of the function.
    
    Parameters:
    
    t - The runtime context.

Interface RichFunction

Method Summary

Method Detail

open

close

getRuntimeContext

getIterationRuntimeContext

setRuntimeContext