Package org.apache.commons.codec.language

Class DoubleMetaphone

java.lang.Object

org.apache.commons.codec.language.DoubleMetaphone

All Implemented Interfaces:

Encoder, StringEncoder

public class DoubleMetaphone
extends Object
implements StringEncoder

Encodes a string into a Double Metaphone value. This Implementation is based on the algorithm by Lawrence Philips.

This class is conditionally thread-safe. The instance field for the maximum code length is mutable setMaxCodeLen(int) but is not volatile, and accesses are not synchronized. If an instance of the class is shared between threads, the caller needs to ensure that suitable synchronization is used to ensure safe publication of the value between threads, and must not invoke setMaxCodeLen(int) after initial setup.

See Also:

• Dr. Dobbs Original Article
• Wikipedia Metaphone
• Double Metaphone C++ source by Lawrence Philips

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
class	DoubleMetaphone.DoubleMetaphoneResult	Stores results, since there is the optional alternate encoding.

Constructor Summary

Constructors

Constructor	Description
DoubleMetaphone()	Constructs a new instance.

Method Summary

Modifier and Type	Method	Description
protected char	charAt(String value, int index)	Gets the character at index index if available, or Character.MIN_VALUE if out of bounds.
protected static boolean	contains(String value, int start, int length, String... criteria)	Tests whether value contains any of the criteria starting at index start and matching up to length length.
String	doubleMetaphone(String value)	Encodes a value with Double Metaphone.
String	doubleMetaphone(String value, boolean alternate)	Encodes a value with Double Metaphone, optionally using the alternate encoding.
Object	encode(Object obj)	Encodes the value using DoubleMetaphone.
String	encode(String value)	Encodes the value using DoubleMetaphone.
int	getMaxCodeLen()	Gets the maxCodeLen.
boolean	isDoubleMetaphoneEqual(String value1, String value2)	Tests whether the Double Metaphone values of two String values are equal.
boolean	isDoubleMetaphoneEqual(String value1, String value2, boolean alternate)	Tests whether the Double Metaphone values of two String values are equal, optionally using the alternate value.
void	setMaxCodeLen(int maxCodeLen)	Sets the maxCodeLen.

Methods inherited from class java.lang.Object

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

Constructor Details

DoubleMetaphone

public DoubleMetaphone()

Constructs a new instance.

Method Details

contains

protected static boolean contains(String value,
 int start,
 int length,
 String... criteria)

Tests whether value contains any of the criteria starting at index start and matching up to length length.

Parameters:

value - The value to test.

start - Where in value to start testing.

length - How many to test.

criteria - The search criteria.

Returns:

Whether there was a match.

charAt

protected char charAt(String value,
 int index)

Gets the character at index index if available, or Character.MIN_VALUE if out of bounds.

Parameters:

value - The String to query.

index - A string index.

Returns:

The character at the index or Character.MIN_VALUE if out of bounds.

doubleMetaphone

public String doubleMetaphone(String value)

Encodes a value with Double Metaphone.

Parameters:

value - String to encode.

Returns:

an encoded string.

doubleMetaphone

public String doubleMetaphone(String value,
 boolean alternate)

Encodes a value with Double Metaphone, optionally using the alternate encoding.

Parameters:

value - String to encode.

alternate - use alternate encode.

Returns:

an encoded string.

encode

public Object encode(Object obj)
              throws EncoderException

Encodes the value using DoubleMetaphone. It will only work if obj is a String (like Metaphone).

Specified by:

encode in interface Encoder

Parameters:

obj - Object to encode (should be of type String).

Returns:

An encoded Object (will be of type String).

Throws:

EncoderException - encode parameter is not of type String.

encode

public String encode(String value)

Encodes the value using DoubleMetaphone.

Specified by:

encode in interface StringEncoder

Parameters:

value - String to encode.

Returns:

An encoded String.

getMaxCodeLen

public int getMaxCodeLen()

Gets the maxCodeLen.

Returns:

the maxCodeLen.

isDoubleMetaphoneEqual

public boolean isDoubleMetaphoneEqual(String value1,
 String value2)

Tests whether the Double Metaphone values of two String values are equal.

Parameters:

value1 - The left-hand side of the encoded String.equals(Object).

value2 - The right-hand side of the encoded String.equals(Object).

Returns:

true if the encoded Strings are equal; false otherwise.

See Also:

• isDoubleMetaphoneEqual(String,String,boolean)

isDoubleMetaphoneEqual

public boolean isDoubleMetaphoneEqual(String value1,
 String value2,
 boolean alternate)

Tests whether the Double Metaphone values of two String values are equal, optionally using the alternate value.

Parameters:

value1 - The left-hand side of the encoded String.equals(Object).

value2 - The right-hand side of the encoded String.equals(Object).

alternate - use the alternate value if true.

Returns:

true if the encoded Strings are equal; false otherwise.

setMaxCodeLen

public void setMaxCodeLen(int maxCodeLen)

Sets the maxCodeLen.

Parameters:

maxCodeLen - The maxCodeLen to set.