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:
    Serialized Form

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static Factory` | `NULL_INSTANCE` Returns null each time

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `ConstantFactory(Object constantToReturn)` Constructor that performs no validation.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `Object` | `create()` Always return constant.
    `Object` | `getConstant()` Gets the constant.
    `static Factory` | `getInstance(Object constantToReturn)` Factory method that performs validation.

    - ### Methods inherited from class java.lang.Object

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

- - ### Field Detail

    - #### NULL_INSTANCE

          public static final Factory NULL_INSTANCE

      Returns null each time

  - ### Constructor Detail

    - #### 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 Detail

    - #### 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

Copyright © 2001–2015 The Apache Software Foundation. All rights reserved.