net.sf.staccatocommons.lang.tuple
Class AbstractTuple

java.lang.Object
  net.sf.staccatocommons.lang.tuple.AbstractTuple

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

Pair, Quadruple, Triple

@Value
@Conditionally(value={net.sf.staccatocommons.restrictions.value.Immutable.class,java.io.Serializable.class})
public abstract class AbstractTuple
extends Object
implements Serializable

A AbstractTuple is a fixed size sequence of heterogeneous objects. They are ConditionallyImmutable and ConditionallySerializable . They are comparable, as long as they components are, too.

Tuples are aimed to be used in those situations where an object that just relates others together is needed. Such object does not encapsulate any business concept nor any specific behavior except of Object.toString(), Object.equals(Object), Object.hashCode() and Comparable#compareTo(Object, Object). Tuples are thus not intended to be used everywhere nor extended, but there are some concrete scenarios where they are useful:

• When immutable components are used, they are valid keys for hashed maps or elements of hashed sets
• When comparable components are used, they are valid keys for sorted maps or elements of sorted sets and sorted lists
• For debugging purposes, when it is needed to print to an string multiple objects.
• When a method needs to return a fixed amount of different results. For example, using 2-components tuple, it is easy to implement a divmod method that returns the quotient and modulus of an integral division, with the signature Tuple2<Integer, Integer> divMod(int x, int y)

Although it is possible to create tuples of arities from 2 to 4 invoking the appropriate constructor, the recommended way of instantiating tuples is using the family of class methods in Tuples named _. Although it looks odd at first glance, combining it with static imports produces quite clean code. For example, using again the divMod method:

  import static net.sf.staccatocommons.lang.tuple._;
  
  ...
  Tuple2<Integer, Integer> divMod(int x, int y)
   return _(x/y, x%y)
  ...
 
 

Author:

flbulgarelli

See Also:

Tuple2, Tuple3, Quadruple, Serialized Form

Nested Class Summary

protected static class

AbstractTuple.TupleState<A>

Method Summary

abstract Object[]	toArray() Converts this tuple into an array
List<Object>	toList() Gets an unmodifiable list containing each components of this tuple as elements

Methods inherited from class java.lang.Object

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

Method Detail

toArray

@NonNull
public abstract Object[] toArray()

Converts this tuple into an array

Returns:

an new Object[] containing each of the elements of this tuple

toList

@NonNull
public List<Object> toList()

Gets an unmodifiable list containing each components of this tuple as elements

Returns:

a non null, unmodifiable list