org.apache.commons.collections4.functors

## Class ConstantFactory<T>

- java.lang.Object
- - org.apache.commons.collections4.functors.ConstantFactory<T>

- All Implemented Interfaces:
    Serializable, Factory<T>

      public class ConstantFactory<T>
      extends Object
      implements Factory<T>, 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:
    3.0
  Version:
    $Id: ConstantFactory.java 1543950 2013-11-20 21:13:35Z tn $
  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(T constantToReturn)` Constructor that performs no validation.

  - ### Method Summary

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

    - ### 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(T constantToReturn)

      Constructor that performs no validation. Use `constantFactory` if you want that.
      Parameters:
        `constantToReturn` - the constant to return each time

  - ### Method Detail

    - #### constantFactory

          public static <T> Factory<T> constantFactory(T constantToReturn)

      Factory method that performs validation.
      Type Parameters:
        `T` - the type of the constant
      Parameters:
        `constantToReturn` - the constant object to return each time in the factory
      Returns:
        the `constant` factory.

    - #### create

          public T create()

      Always return constant.
      Specified by:
        `create` in interface `Factory<T>`
      Returns:
        the stored constant value

    - #### getConstant

          public T getConstant()

      Gets the constant.
      Returns:
        the constant
      Since:
        3.1

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