org.apache.pig.builtin
Class RollupDimensions

java.lang.Object
  extended by org.apache.pig.EvalFunc<DataBag>
      extended by org.apache.pig.builtin.RollupDimensions

public class RollupDimensions
extends EvalFunc<DataBag>

Produces a DataBag with hierarchy of values (from the most detailed level of aggregation to most general level of aggregation) of the specified dimensions For example, (a, b, c) will produce the following bag:

 { (a, b, c), (a, b, null), (a, null, null), (null, null, null) }
 


Nested Class Summary
 
Nested classes/interfaces inherited from class org.apache.pig.EvalFunc
EvalFunc.SchemaType
 
Field Summary
 
Fields inherited from class org.apache.pig.EvalFunc
log, pigLogger, reporter, returnType
 
Constructor Summary
RollupDimensions()
           
RollupDimensions(String allMarker)
           
 
Method Summary
 DataBag exec(Tuple tuple)
          This callback method must be implemented by all subclasses.
 Schema outputSchema(Schema input)
          Report the schema of the output of this UDF.
 
Methods inherited from class org.apache.pig.EvalFunc
finish, getArgToFuncMapping, getCacheFiles, getInputSchema, getLogger, getPigLogger, getReporter, getReturnType, getSchemaName, getSchemaType, isAsynchronous, progress, setInputSchema, setPigLogger, setReporter, setUDFContextSignature, warn
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

RollupDimensions

public RollupDimensions()

RollupDimensions

public RollupDimensions(String allMarker)
Method Detail

exec

public DataBag exec(Tuple tuple)
             throws IOException
Description copied from class: EvalFunc
This callback method must be implemented by all subclasses. This is the method that will be invoked on every Tuple of a given dataset. Since the dataset may be divided up in a variety of ways the programmer should not make assumptions about state that is maintained between invocations of this method.

Specified by:
exec in class EvalFunc<DataBag>
Parameters:
tuple - the Tuple to be processed.
Returns:
result, of type T.
Throws:
IOException

outputSchema

public Schema outputSchema(Schema input)
Description copied from class: EvalFunc
Report the schema of the output of this UDF. Pig will make use of this in error checking, optimization, and planning. The schema of input data to this UDF is provided.

The default implementation interprets the OutputSchema annotation, if one is present. Otherwise, it returns null (no known output schema).

Overrides:
outputSchema in class EvalFunc<DataBag>
Parameters:
input - Schema of the input
Returns:
Schema of the output


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