org.organicdesign.fp.oneOf

Class OneOf4<A,B,C,D>

java.lang.Object

org.organicdesign.fp.oneOf.OneOf4<A,B,C,D>

public abstract class OneOf4<A,B,C,D>
extends Object

Holds one of 4 values. See OneOf2 for a full description. If you're passing the same type, you probably want a tuple instead.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	OneOf4(Object o, Class<A> aClass, Class<B> bClass, Class<C> cClass, Class<D> dClass, int index) Protected constructor for subclassing.

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object other)
int	hashCode()
<R> R	match(Fn1<A,R> fa, Fn1<B,R> fb, Fn1<C,R> fc, Fn1<D,R> fd) Languages that have union types built in have a match statement that works like this method.
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

OneOf4

protected OneOf4(Object o,
                 Class<A> aClass,
                 Class<B> bClass,
                 Class<C> cClass,
                 Class<D> dClass,
                 int index)

Protected constructor for subclassing.

Parameters:

o - the item (may be null)

aClass - class 0 (to have at runtime for descriptive error messages and toString()).

bClass - class 1 (to have at runtime for descriptive error messages and toString()).

cClass - class 2 (to have at runtime for descriptive error messages and toString()).

dClass - class 3 (to have at runtime for descriptive error messages and toString()).

index - 0 means this represents an A, 1 represents a B, 2 represents a C, 3 means D

Method Detail

match

public <R> R match(Fn1<A,R> fa,
                   Fn1<B,R> fb,
                   Fn1<C,R> fc,
                   Fn1<D,R> fd)

Languages that have union types built in have a match statement that works like this method. Exactly one of these functions will be executed - determined by which type of item this object holds.

Parameters:

fa - the function to be executed if this OneOf stores the first type.

fb - the function to be executed if this OneOf stores the second type.

fc - the function to be executed if this OneOf stores the third type.

fd - the function to be executed if this OneOf stores the fourth type.

Returns:

the return value of whichever function is executed.

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object other)

Overrides:

equals in class Object

toString

public String toString()

Overrides:

toString in class Object