Package org.apache.commons.collections.functors

Class ConstantFactory

java.lang.Object
org.apache.commons.collections.functors.ConstantFactory
All Implemented Interfaces:
Serializable, Factory
public class ConstantFactory extends Object implements Factory, Serializable
Factory 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
Version:
$Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $
Author:
Stephen Colebourne
See Also:

  • Field Details

    • NULL_INSTANCE

      public static final Factory NULL_INSTANCE
      Returns null each time

  • Constructor Details

    • ConstantFactory

      public ConstantFactory(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 Factory getInstance(Object constantToReturn)
      Factory method that performs validation.
      Parameters:
      constantToReturn - the constant object to return each time in the factory
      Returns:
      the constant factory.

    • create

      public Object create()
      Always return constant.
      Specified by:
      create in interface Factory
      Returns:
      the stored constant value

    • getConstant

      public Object getConstant()
      Gets the constant.
      Returns:
      the constant
      Since:
      Commons Collections 3.1