cascading.operation.regex
Class RegexParser

java.lang.Object
  cascading.operation.BaseOperation<C>
      cascading.operation.regex.RegexOperation<Matcher>
          cascading.operation.regex.RegexParser

All Implemented Interfaces:

Function<Matcher>, Operation<Matcher>, Serializable

public class RegexParser
extends RegexOperation<Matcher>
implements Function<Matcher>

Class RegexParser is used to extract a matched regex from an incoming argument value.

See Also:

Serialized Form

Field Summary

Fields inherited from class cascading.operation.regex.RegexOperation

patternString

Fields inherited from class cascading.operation.BaseOperation

fieldDeclaration, numArgs, trace

Fields inherited from interface cascading.operation.Operation

ANY

Constructor Summary

RegexParser(Fields fieldDeclaration, String patternString)
Constructor RegexParser creates a new RegexParser instance, where the argument Tuple value is matched and returned as the given Field.

RegexParser(Fields fieldDeclaration, String patternString, int[] groups)
Constructor RegexParser creates a new RegexParser instance, where the patternString is a regular expression with match groups and whose groups designated by groups are stored in the named fieldDeclarations.

RegexParser(String patternString)
Constructor RegexParser creates a new RegexParser instance, where the argument Tuple value is matched and returned in a new Tuple.

RegexParser(String patternString, int[] groups)
Constructor RegexParser creates a new RegexParser instance, where the patternString is a regular expression with match groups and whose groups designated by groups are stored in the appropriate number of new fields.

Method Summary

void	operate(FlowProcess flowProcess, FunctionCall<Matcher> functionCall) Method operate provides the implementation of this Function.
void	prepare(FlowProcess flowProcess, OperationCall<Matcher> operationCall) Method prepare does nothing, and may safely be overridden.

Methods inherited from class cascading.operation.regex.RegexOperation

getPattern

Methods inherited from class cascading.operation.BaseOperation

cleanup, getFieldDeclaration, getNumArgs, getTrace, printOperationInternal, toString, toStringInternal

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface cascading.operation.Operation

cleanup, getFieldDeclaration, getNumArgs

Constructor Detail

RegexParser

public RegexParser(String patternString)

Constructor RegexParser creates a new RegexParser instance, where the argument Tuple value is matched and returned in a new Tuple.

If the given patternString declares regular expression groups, each group will be returned as a value in the resulting Tuple. If no groups are declared, the match will be returned as the only value in the resulting Tuple.

The fields returned will be Fields.UNKNOWN, so a variable number of values may be emitted based on the regular expression given.

Parameters:

patternString - of type String

RegexParser

public RegexParser(Fields fieldDeclaration,
                   String patternString)

Constructor RegexParser creates a new RegexParser instance, where the argument Tuple value is matched and returned as the given Field.

If the given patternString declares regular expression groups, each group will be returned as a value in the resulting Tuple. If no groups are declared, the match will be returned as the only value in the resulting Tuple.

If the number of fields in the fieldDeclaration does not match the number of groups matched, an OperationException will be thrown during runtime.

To overcome this, either use the constructors that take an array of groups, or use the (?: ...) sequence to tell the regular expression matcher to not capture the group.

Parameters:

fieldDeclaration - of type Fields

patternString - of type String

RegexParser

public RegexParser(String patternString,
                   int[] groups)

Constructor RegexParser creates a new RegexParser instance, where the patternString is a regular expression with match groups and whose groups designated by groups are stored in the appropriate number of new fields.

The number of resulting fields will match the number of groups given (groups.length).

Parameters:

patternString - of type String

groups - of type int[]

RegexParser

public RegexParser(Fields fieldDeclaration,
                   String patternString,
                   int[] groups)

Constructor RegexParser creates a new RegexParser instance, where the patternString is a regular expression with match groups and whose groups designated by groups are stored in the named fieldDeclarations.

Parameters:

fieldDeclaration - of type Fields

patternString - of type String

groups - of type int[]

Method Detail

prepare

public void prepare(FlowProcess flowProcess,
                    OperationCall<Matcher> operationCall)

Description copied from class: BaseOperation

Method prepare does nothing, and may safely be overridden.

Specified by:

prepare in interface Operation<Matcher>

Overrides:

prepare in class BaseOperation<Matcher>

operate

public void operate(FlowProcess flowProcess,
                    FunctionCall<Matcher> functionCall)

Description copied from interface: Function

Method operate provides the implementation of this Function.

Specified by:

operate in interface Function<Matcher>

Parameters:

flowProcess - of type FlowProcess

functionCall - of type FunctionCall

See Also:

Function.operate(cascading.flow.FlowProcess,cascading.operation.FunctionCall)