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org.apache.commons.collections.functors

Class ConstantTransformer

java.lang.Object
|
+--org.apache.commons.collections.functors.ConstantTransformer

All Implemented Interfaces:
Transformer, Serializable


public class ConstantTransformer
extends java.lang.Object
implements Transformer, Serializable

Transformer implementation that returns the same constant each time.

No check is made that the object is immutable. In general, only immutable objects should use the constant factory. Mutable objects should use the prototype factory.

Since:
Commons Collections 3.0
Author:
Stephen Colebourne

Field Summary

static Transformer

NULL_INSTANCE

Returns null each time

Constructor Summary

ConstantTransformer(Object constantToReturn)

Constructor that performs no validation.

Method Summary

static Transformer

getInstance(Object constantToReturn)

Transformer method that performs validation.

Object

transform(Object input)

Always return constant.

Field Details

NULL_INSTANCE

public static final Transformer NULL_INSTANCE

Returns null each time

Constructor Details

ConstantTransformer

public ConstantTransformer(Object constantToReturn)

Constructor that performs no validation. Use getInstance if you want that.

Parameters:
constantToReturn - the constant to return each time

Method Details

getInstance

public static Transformer getInstance(Object constantToReturn)

Transformer method that performs validation.

Parameters:
constantToReturn - the constant object to return each time in the factory
Returns:
the constant factory.

transform

public Object transform(Object input)

Always return constant.

Parameters:
input