org.apache.pig.piggybank.evaluation.string
Class RegexExtract

java.lang.Object
  extended by org.apache.pig.EvalFunc<String>
      extended by org.apache.pig.piggybank.evaluation.string.RegexExtract

public class RegexExtract
extends EvalFunc<String>

Syntax:
String RegexExtract(String expression, String regex, int match_index).
Input:
expression-source string.
regex-regular expression.
match_index-index of the group to extract.
Output:
extracted group, if fail, return null.


Field Summary
 
Fields inherited from class org.apache.pig.EvalFunc
log, pigLogger, reporter, returnType
 
Constructor Summary
RegexExtract()
           
 
Method Summary
 String exec(Tuple input)
          This callback method must be implemented by all subclasses.
 List<FuncSpec> getArgToFuncMapping()
           
 Schema outputSchema(Schema input)
           
 
Methods inherited from class org.apache.pig.EvalFunc
finish, getLogger, getPigLogger, getReporter, getReturnType, getSchemaName, isAsynchronous, progress, setPigLogger, setReporter, warn
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

RegexExtract

public RegexExtract()
Method Detail

outputSchema

public Schema outputSchema(Schema input)
Overrides:
outputSchema in class EvalFunc<String>
Parameters:
input - Schema of the input
Returns:
Schema of the output

exec

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

getArgToFuncMapping

public List<FuncSpec> getArgToFuncMapping()
                                   throws FrontendException
Overrides:
getArgToFuncMapping in class EvalFunc<String>
Returns:
A List containing FuncSpec objects representing the Function class which can handle the inputs corresponding to the schema in the objects
Throws:
FrontendException


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