public class FirstTupleFromBag extends SimpleEvalFunc<org.apache.pig.data.Tuple> implements org.apache.pig.Accumulator<org.apache.pig.data.Tuple>
define FirstTupleFromBag datafu.pig.bags.FirstTupleFromBag();
-- input:
-- ({(a,1)})
input = LOAD 'input' AS (B: bag {T: tuple(alpha:CHARARRAY, numeric:INT)});
output = FOREACH input GENERATE FirstTupleFromBag(B, null);
-- output:
-- (a,1)
Constructor and Description |
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FirstTupleFromBag() |
Modifier and Type | Method and Description |
---|---|
void |
accumulate(org.apache.pig.data.Tuple tuple) |
org.apache.pig.data.Tuple |
call(org.apache.pig.data.DataBag bag,
org.apache.pig.data.Tuple defaultValue) |
void |
cleanup() |
org.apache.pig.data.Tuple |
getValue() |
org.apache.pig.impl.logicalLayer.schema.Schema |
outputSchema(org.apache.pig.impl.logicalLayer.schema.Schema input)
Override outputSchema so we can verify the input schema at pig compile time, instead of runtime
|
exec, getReturnType
getContextProperties, getInstanceName, getInstanceProperties, onReady, setUDFContextSignature
public void accumulate(org.apache.pig.data.Tuple tuple) throws java.io.IOException
accumulate
in interface org.apache.pig.Accumulator<org.apache.pig.data.Tuple>
java.io.IOException
public void cleanup()
cleanup
in interface org.apache.pig.Accumulator<org.apache.pig.data.Tuple>
public org.apache.pig.data.Tuple getValue()
getValue
in interface org.apache.pig.Accumulator<org.apache.pig.data.Tuple>
public org.apache.pig.data.Tuple call(org.apache.pig.data.DataBag bag, org.apache.pig.data.Tuple defaultValue) throws java.io.IOException
java.io.IOException
public org.apache.pig.impl.logicalLayer.schema.Schema outputSchema(org.apache.pig.impl.logicalLayer.schema.Schema input)
SimpleEvalFunc
outputSchema
in class SimpleEvalFunc<org.apache.pig.data.Tuple>
input
- input schema