org.apache.pig.builtin
Class REPLACE

java.lang.Object
  extended by org.apache.pig.EvalFunc<String>
      extended by org.apache.pig.builtin.REPLACE
Direct Known Subclasses:
REPLACE

public class REPLACE
extends EvalFunc<String>

REPLACE implements eval function to replace part of a string. Example: A = load 'mydata' as (name); B = foreach A generate REPLACE(name, 'blabla', 'bla'); The first argument is a string on which to perform the operation. The second argument is treated as a regular expression. The third argument is the replacement string. This is a wrapper around Java's String.replaceAll(String, String);


Field Summary
 
Fields inherited from class org.apache.pig.EvalFunc
log, pigLogger, reporter, returnType
 
Constructor Summary
REPLACE()
           
 
Method Summary
 String exec(Tuple input)
          Method invoked on every tuple during foreach evaluation
 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, 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

REPLACE

public REPLACE()
Method Detail

exec

public String exec(Tuple input)
            throws IOException
Method invoked on every tuple during foreach evaluation

Specified by:
exec in class EvalFunc<String>
Parameters:
input - tuple; first column is assumed to have the column to convert
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.

Overrides:
outputSchema in class EvalFunc<String>
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<String>
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