org.apache.pig.builtin
Class BagToString

java.lang.Object
  extended by org.apache.pig.EvalFunc<String>
      extended by org.apache.pig.builtin.BagToString

public class BagToString
extends EvalFunc<String>

Flatten a bag into a string. This UDF will use the character '_' as the default delimiter if one is not provided. Example: bag = {(a),(b),(c)} BagToString(bag) -> 'a_b_c' BagToString(bag, '+') -> 'a+b+c' bag = {(a,b), (c,d), (e,f)} BagToString(bag) --> 'a_b_c_d_e_f' If input bag is null, this UTF will return 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
BagToString()
           
 
Method Summary
 String exec(Tuple inputTuple)
          This callback method must be implemented by all subclasses.
 Schema outputSchema(Schema inputSchema)
          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

BagToString

public BagToString()
Method Detail

exec

public String exec(Tuple inputTuple)
            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<String>
Parameters:
inputTuple - the Tuple to be processed.
Returns:
result, of type T.
Throws:
IOException

outputSchema

public Schema outputSchema(Schema inputSchema)
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<String>
Parameters:
inputSchema - Schema of the input
Returns:
Schema of the output


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