kodkod.instance

Class Tuple

java.lang.Object

kodkod.instance.Tuple

public abstract class Tuple
extends Object

Represents a sequence of atoms drawn from a given universe. Note that a Tuple of arity n whose atoms belong to a Universe u encodes an n-digit number in base u.size. The decimal representation of this number is taken to be the index of the tuple in an n-dimensional space over the Universe u.

Author:

Emina Torlak

Specfields:

arity: int

universe: Universe

atoms: [0..arity)->one Object

Invariants:

atoms[int] in universe.atoms[int]

Constructor Summary

Constructors

Constructor and Description
Tuple()

Method Summary

Modifier and Type	Method and Description
abstract int	arity() Returns the arity of this tuple.
abstract Object	atom(int i) Returns the atom at the specified index
abstract int	atomIndex(int i) Returns the index of the ith atom as given by this.universe.
abstract boolean	contains(Object atom) Returns true if atom is in this tuple, otherwise returns false.
boolean	equals(Object o) Returns true if o is a tuple with the same sequence of atoms as this, drawn from the same universe as this.
int	hashCode() Returns a hash code based on the tuple's arity, index, and the hash code of its universe, so that the general contract of Object.hashCode is obeyed.
abstract int	index() A Tuple encodes a number with this.arity digits in radix this.universe.size; a Tuple's index is the decimal representation of this number.
abstract Tuple	product(Tuple tuple) Returns the cross product of this and the specified tuple.
String	toString()
abstract Universe	universe() Returns the universe from which the atoms in this tuple are drawn.

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

Tuple

public Tuple()

Method Detail

arity

public abstract int arity()

Returns the arity of this tuple.

Returns:

this.arity

atom

public abstract Object atom(int i)

Returns the atom at the specified index

Returns:

this.atoms[i]

Throws:

IndexOutOfBoundsException - i < 0 || i >= this.arity

atomIndex

public abstract int atomIndex(int i)

Returns the index of the ith atom as given by this.universe. The effect of this method is the same as calling this.universe.index(this.atom(i)).

Returns:

this.universe.index(this.atoms[i])

Throws:

IndexOutOfBoundsException - i < 0 || i >= this.arity

contains

public abstract boolean contains(Object atom)

Returns true if atom is in this tuple, otherwise returns false.

Returns:

atom in this.atoms[int]

Throws:

IllegalArgumentException - atom !in this.universe.atoms[int]

equals

public boolean equals(Object o)

Returns true if o is a tuple with the same sequence of atoms as this, drawn from the same universe as this. Otherwise returns false.

Overrides:

equals in class Object

Returns:

o in Tuple && o.universe = this.universe && o.atoms = this.atoms

hashCode

public int hashCode()

Returns a hash code based on the tuple's arity, index, and the hash code of its universe, so that the general contract of Object.hashCode is obeyed.

Overrides:

hashCode in class Object

Returns:

the hashcode for this tuple

index

public abstract int index()

A Tuple encodes a number with this.arity digits in radix this.universe.size; a Tuple's index is the decimal representation of this number.

Returns:

sum({i: [0..arity) | universe.index(atoms[i]) * universe.size^(arity - 1 - i)})

product

public abstract Tuple product(Tuple tuple)

Returns the cross product of this and the specified tuple.

Returns:

{t : Tuple | t.atoms = this.atoms->tuple.atoms}

Throws:

NullPointerException - tuple = null

IllegalArgumentException - tuple.universe != this.universe

toString

public String toString()

Overrides:

toString in class Object

See Also:

Object.toString()

universe

public abstract Universe universe()

Returns the universe from which the atoms in this tuple are drawn.

Returns:

this.universe