ConstantFactory (Apache Commons Collections 4.2 API)

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

See Also:

Serialized Form

Field Summary

Fields
Modifier and Type Field Description

static Factory NULL_INSTANCE
Returns null each time

Constructor Summary

Constructors
Constructor Description

ConstantFactory(T constantToReturn)
Constructor that performs no validation.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	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