uk.co.strangeskies.collection.tuple

Class Tuple<H,T extends Tuple<?,?>>

java.lang.Object

uk.co.strangeskies.collection.tuple.Tuple<H,T>

Type Parameters:

H - The type of the head item.

T - The fully qualified type of the tail Tuple.

Direct Known Subclasses:

EmptyTuple, Pair, Quadruple, Quintuple, Triple, Unit

public class Tuple<H,T extends Tuple<?,?>>
extends java.lang.Object

A tuple entry, parameterised recursively with type information for each subsequent entry. Currently entries must be non-null.

Constructor Summary

Constructors

Constructor and Description
Tuple(H head, T tail) Create a Tuple instance with the given values for its head and tail entries.

Method Summary

Modifier and Type	Method and Description
boolean	equals(java.lang.Object other)
H	getHead() Return the value of the head entry.
int	getSize() The number of entries in this tuple, including the head and every entry in the tail.
T	getTail() Return the value of the tail entry.
boolean	hasTail() Does this tuple have a tail, or is it terminating.
<I> Tuple<I,T>	mapHead(java.util.function.Function<? super H,? extends I> headMap) Map the value of the head entry.
<U extends Tuple<?,?>> Tuple<H,U>	mapTail(java.util.function.Function<T,U> tailMap) Map the value of the tail entry.
T	next(H head)
<P> Tuple<P,Tuple<H,T>>	prepend(P prepend) This method prepends the tuple with another tuple entry with the given value, resulting in a tuple one extra in size.
void	setHead(H head) Set the value of the head entry.
void	setTail(T tail) Set the tuple entry which represents the tail of this tuple.
protected int	tailCounter(int size)
java.lang.String	toString()
protected java.lang.String	toSubStrings()

Methods inherited from class java.lang.Object

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

Constructor Detail

Tuple

public Tuple(H head,
             T tail)

Create a Tuple instance with the given values for its head and tail entries.

Parameters:

head - The head item.

tail - The tail Tuple.

Method Detail

getHead

public H getHead()

Return the value of the head entry.

Returns:

Head entry/

setHead

public void setHead(H head)

Set the value of the head entry.

Parameters:

head - New head value. This parameter should be non-null.

mapHead

public <I> Tuple<I,T> mapHead(java.util.function.Function<? super H,? extends I> headMap)

Map the value of the head entry.

Type Parameters:

I - The type of the head of the new Tuple.

Parameters:

headMap - A mapping to a new head value. The result should be non-null.

Returns:

A new derived tuple with the head value transformed by the given mapping.

mapTail

public <U extends Tuple<?,?>> Tuple<H,U> mapTail(java.util.function.Function<T,U> tailMap)

Map the value of the tail entry.

Type Parameters:

U - The type of the tail of the new Tuple.

Parameters:

tailMap - A mapping to a new tail value. The result should be non-null.

Returns:

A new derived tuple with the tail value transformed by the given mapping.

getTail

public T getTail()

Return the value of the tail entry.

Returns:

Tail value, which is itself a tuple.

setTail

public void setTail(T tail)

Set the tuple entry which represents the tail of this tuple.

Parameters:

tail - A new tuple of the exact expected type of the tail of this tuple.

hasTail

public boolean hasTail()

Does this tuple have a tail, or is it terminating.

Returns:

True if the tuple has a tail, false otherwise.

getSize

public int getSize()

The number of entries in this tuple, including the head and every entry in the tail.

Returns:

The number of entries.

tailCounter

protected int tailCounter(int size)

prepend

public <P> Tuple<P,Tuple<H,T>> prepend(P prepend)

This method prepends the tuple with another tuple entry with the given value, resulting in a tuple one extra in size. The receiving tuple remains unchanged.

Type Parameters:

P - The type of the item to prepend.

Parameters:

prepend - The head value of the new tuple.

Returns:

A new tuple instance with the given value as its head, and this tuple as its tail.

next

public T next(H head)

Parameters:

head - The value to set head with.

Returns:

The tail of the tuple, ready to be chained with another invocation of next(Object) such that every value can be set.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

toSubStrings

protected java.lang.String toSubStrings()

equals

public boolean equals(java.lang.Object other)

Overrides:

equals in class java.lang.Object