org.apache.pig.backend.hadoop.executionengine.physicalLayer
Class POStatus

java.lang.Object
  extended by org.apache.pig.backend.hadoop.executionengine.physicalLayer.POStatus

public class POStatus
extends Object

POStatus is a set of flags used to communicate the status of Pig's operator pipeline to consumers.


Field Summary
static byte STATUS_BATCH_OK
          Successful processing of a batch.
static byte STATUS_EARLY_TERMINATION
          This signals that an accumulative UDF has already finished.
static byte STATUS_EOP
          STATUS_EOP indicates that no output was produced, and no further outputs will be produced (e.g.
static byte STATUS_EOS
          This is currently only used in communications between ExecutableManager and POStream.
static byte STATUS_ERR
          STATUS_ERR indicates that there was a problem while trying to produce a result.
static byte STATUS_NULL
          STATUS_NULL indicates that no output was produced, but there may be more results.
static byte STATUS_OK
          STATUS_OK indicates that the pull on the operator pipeline resulted in a valid output.
 
Constructor Summary
POStatus()
           
 
Method Summary
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

STATUS_OK

public static final byte STATUS_OK
STATUS_OK indicates that the pull on the operator pipeline resulted in a valid output.

See Also:
Constant Field Values

STATUS_NULL

public static final byte STATUS_NULL
STATUS_NULL indicates that no output was produced, but there may be more results. This can happen if a value is filtered out or an empty bag is flattened. A caller will typically ignore the output and try again after seeing STATUS_NULL. This does NOT indicate that the output is the value 'null' (which is possible in expressions). This is represented as 'null' with STATUS_OK.

See Also:
Constant Field Values

STATUS_ERR

public static final byte STATUS_ERR
STATUS_ERR indicates that there was a problem while trying to produce a result. This should be remembered and fed back to the user.

See Also:
Constant Field Values

STATUS_EOP

public static final byte STATUS_EOP
STATUS_EOP indicates that no output was produced, and no further outputs will be produced (e.g. all attached inputs have been consumed or a limit has reached its threshold). A caller will typically terminate or attach new inputs on seeing this status.

See Also:
Constant Field Values

STATUS_EOS

public static final byte STATUS_EOS
This is currently only used in communications between ExecutableManager and POStream. It indicates the end of Streaming output (i.e. output from streaming binary).

See Also:
Constant Field Values

STATUS_BATCH_OK

public static final byte STATUS_BATCH_OK
Successful processing of a batch. This is used for accumulative UDFs.

See Also:
Constant Field Values

STATUS_EARLY_TERMINATION

public static final byte STATUS_EARLY_TERMINATION
This signals that an accumulative UDF has already finished.

See Also:
Constant Field Values
Constructor Detail

POStatus

public POStatus()


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