org.apache.tez.runtime.api

Interface Input

All Known Subinterfaces:

LogicalInput

All Known Implementing Classes:

AbstractLogicalInput, MergedLogicalInput

@InterfaceAudience.Public
public interface Input

Represents an input through which a Processor receives data on an edge.

This interface has methods which can be used by a Processor to control execution of this Input and read data from it. Actual implementations are expected to derive from AbstractLogicalInput

Method Summary

Modifier and Type	Method and Description
Reader	getReader() Gets an instance of the Reader for this Output
void	start() Start any processing that the Input may need to perform.

Method Detail

start

void start()
    throws Exception

Start any processing that the Input may need to perform. It is the responsibility of the Processor to start Inputs. This typically acts as a signal to Inputs to start any Processing that they may require. A blocking implementation of this method should not be used as a mechanism to determine when an Input is actually ready. This method may be invoked by the framework under certain circumstances, and as such requires the implementation to be non-blocking. Inputs must be written to handle multiple start invocations - typically honoring only the first one.

Throws:

Exception

getReader

Reader getReader()
          throws Exception

Gets an instance of the Reader for this Output

Returns:

Gets an instance of the Reader for this Output

Throws:

Exception - if an error occurs