Package org.apache.nutch.indexer.replace

Class FieldReplacer

java.lang.Object

org.apache.nutch.indexer.replace.FieldReplacer

public class FieldReplacer
extends Object

POJO to store a filename, its match pattern and its replacement string. A checkAndReplace method is provided where you can simultaneously check if the field matches this replacer and if the pattern matches your field value.

Author:

Peter Ciuffetti

Constructor Summary

Constructors

Constructor	Description
FieldReplacer(String fieldName, String pattern, String replacement, Integer flags)	Field replacer with the input and output field the same.
FieldReplacer(String fieldName, String toFieldName, String pattern, String replacement, Integer flags)	Create a FieldReplacer for a field.

Method Summary

Modifier and Type	Method	Description
String	checkAndReplace(String fieldName, String value)	Return a replacement value for a field.
String	getFieldName()
Pattern	getPattern()
String	getReplacement()
String	getToFieldName()
boolean	isValid()	Does this FieldReplacer have a valid fieldname and pattern?
String	replace(String value)	Return the replacement value for a field value.

Methods inherited from class java.lang.Object

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

Constructor Detail

FieldReplacer

public FieldReplacer(String fieldName,
                     String toFieldName,
                     String pattern,
                     String replacement,
                     Integer flags)

Create a FieldReplacer for a field. Any pattern exceptions are caught within this constructor and the object is marked inValid. The error will be logged. This prevents this caller from attempting invalid replacements.

Parameters:

fieldName - the name of the source field to operate on. Required.

toFieldName - the name of the target field. Required.

pattern - the pattern the field must match. Required.

replacement - the replacement string

flags - the Pattern flags value, or null if no flags are needed

FieldReplacer

public FieldReplacer(String fieldName,
                     String pattern,
                     String replacement,
                     Integer flags)

Field replacer with the input and output field the same.

Parameters:

fieldName - the name of the source field to operate on. Required.

pattern - the pattern the field must match. Required.

replacement - the replacement string

flags - the Integer flags value, or null if no flags are needed

Method Detail

getFieldName

public String getFieldName()

getToFieldName

public String getToFieldName()

getPattern

public Pattern getPattern()

getReplacement

public String getReplacement()

isValid

public boolean isValid()

Does this FieldReplacer have a valid fieldname and pattern?

Returns:

true if fieldname and pattern are valid, false otherwise

replace

public String replace(String value)

Return the replacement value for a field value. This does not check for a matching field; the caller must decide if this FieldReplacer should operate on this value by checking getFieldName(). The method returns the value with the replacement. If the value returned is not different then eiher the pattern didn't match or the replacement was a no-op.

Parameters:

value - the value to replace

Returns:

the replaced value

checkAndReplace

public String checkAndReplace(String fieldName,
                              String value)

Return a replacement value for a field. This is designed to fail fast and trigger a replacement only when necessary. If this method returns null, either the field does not match or the value does not match the pattern (or possibly the pattern is invalid). So only if the method returns a non-null value will you need to replace the value for the field.

Parameters:

fieldName - the name of the field you are checking

value - the value of the field you are checking

Returns:

a replacement value. If null, either the field does not match or the value does not match.