org.apache.pig.builtin
Class STRSPLIT

java.lang.Object
  extended by org.apache.pig.EvalFunc<Tuple>
      extended by org.apache.pig.builtin.STRSPLIT
Direct Known Subclasses:
Split

public class STRSPLIT
extends EvalFunc<Tuple>

Wrapper around Java's String.split
input tuple: first column is assumed to have a string to split;
the optional second column is assumed to have the delimiter or regex to split on;
if not provided, it's assumed to be '\s' (space)
the optional third column may provide a limit to the number of results.
If limit is not provided, 0 is assumed, as per Java's split().


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
STRSPLIT()
           
 
Method Summary
 Tuple exec(Tuple input)
          Wrapper around Java's String.split
 List<FuncSpec> getArgToFuncMapping()
          Allow a UDF to specify type specific implementations of itself.
 Schema outputSchema(Schema input)
          Report the schema of the output of this UDF.
 
Methods inherited from class org.apache.pig.EvalFunc
finish, 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

STRSPLIT

public STRSPLIT()
Method Detail

exec

public Tuple exec(Tuple input)
           throws IOException
Wrapper around Java's String.split

Specified by:
exec in class EvalFunc<Tuple>
Parameters:
input - tuple; first column is assumed to have a string to split; the optional second column is assumed to have the delimiter or regex to split on;
if not provided, it's assumed to be '\s' (space) the optional third column may provide a limit to the number of results.
If limit is not provided, 0 is assumed, as per Java's split().
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<Tuple>
Parameters:
input - Schema of the input
Returns:
Schema of the output

getArgToFuncMapping

public List<FuncSpec> getArgToFuncMapping()
                                   throws FrontendException
Description copied from class: EvalFunc
Allow a UDF to specify type specific implementations of itself. For example, an implementation of arithmetic sum might have int and float implementations, since integer arithmetic performs much better than floating point arithmetic. Pig's typechecker will call this method and using the returned list plus the schema of the function's input data, decide which implementation of the UDF to use.

Overrides:
getArgToFuncMapping in class EvalFunc<Tuple>
Returns:
A List containing FuncSpec objects representing the EvalFunc class which can handle the inputs corresponding to the schema in the objects. Each FuncSpec should be constructed with a schema that describes the input for that implementation. For example, the sum function above would return two elements in its list:
  1. FuncSpec(this.getClass().getName(), new Schema(new Schema.FieldSchema(null, DataType.DOUBLE)))
  2. FuncSpec(IntSum.getClass().getName(), new Schema(new Schema.FieldSchema(null, DataType.INTEGER)))
This would indicate that the main implementation is used for doubles, and the special implementation IntSum is used for ints.
Throws:
FrontendException


Copyright © 2007-2012 The Apache Software Foundation