edu.rice.cs.plt.iter
Class FiniteSequenceIterable<T>

java.lang.Object
  edu.rice.cs.plt.iter.AbstractIterable<T>
      edu.rice.cs.plt.iter.TruncatedIterable<T>
          edu.rice.cs.plt.iter.FiniteSequenceIterable<T>

All Implemented Interfaces:

SizedIterable<T>, Composite, Serializable, Iterable<T>

public class FiniteSequenceIterable<T>
extends TruncatedIterable<T>

An iterable representing a finite sequence. The sequence is defined by an initial value and a successor function (described by a Lambda), along with a size that truncates the (otherwise infinite) list. This is a trivial extension to TruncatedIterable, but does add optimized implementations of size() and hasFixedSize() (since the nature of the nested iterable is known).

See Also:

Serialized Form

Field Summary

Fields inherited from class edu.rice.cs.plt.iter.TruncatedIterable

_size

Constructor Summary

FiniteSequenceIterable(T initial, Lambda<? super T,? extends T> successor, int size)

Method Summary

boolean	hasFixedSize() true if this iterable is known to have a fixed size.
boolean	isStatic() Always false: results of a lambda may be arbitrary.
static <T> FiniteSequenceIterable<T>	make(T initial, Lambda<? super T,? extends T> successor, int size) Call the constructor (allows T to be inferred)
static <T> FiniteSequenceIterable<T>	makeCopies(T value, int copies) Create a sequence containing copies instances of the given value.
static FiniteSequenceIterable<Integer>	makeIntegerSequence(int start, int end) Create a simple sequence containing the numbers between start and end (inclusive).
static <T> SnapshotIterable<T>	makeSnapshot(T initial, Lambda<? super T,? extends T> successor, int size) Create a FiniteSequenceIterable and wrap it in a SnapshotIterable, forcing immediate evaluation of the sequence.
int	size() Return size, unless the nested iterable is smaller than size; in that case, returns the iterable's size.
int	size(int bound) Compute the number of elements in the iterable, up to the given bound.

Methods inherited from class edu.rice.cs.plt.iter.TruncatedIterable

compositeHeight, compositeSize, isEmpty, isInfinite, iterator, make, makeSnapshot

Methods inherited from class edu.rice.cs.plt.iter.AbstractIterable

equals, hashCode, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

FiniteSequenceIterable

public FiniteSequenceIterable(T initial,
                              Lambda<? super T,? extends T> successor,
                              int size)

Parameters:

initial - The first value in the sequence

successor - A function that, given the nth sequence value, produces the n+1st value

size - The number of elements in the sequence

Throws:

IllegalArgumentException - If size is less than 0

Method Detail

size

public int size()

Description copied from class: TruncatedIterable

Return size, unless the nested iterable is smaller than size; in that case, returns the iterable's size.

Specified by:

size in interface SizedIterable<T>

Overrides:

size in class TruncatedIterable<T>

size

public int size(int bound)

Description copied from interface: SizedIterable

Compute the number of elements in the iterable, up to the given bound. If the size is infinite or greater than bound, bound is returned.

Specified by:

size in interface SizedIterable<T>

Overrides:

size in class TruncatedIterable<T>

Parameters:

bound - Maximum result. Assumed to be nonnegative.

hasFixedSize

public boolean hasFixedSize()

Description copied from interface: SizedIterable

true if this iterable is known to have a fixed size. This is the case if the iterable is immutable, or if changes can only replace values, not remove or add them. An infinite iterable may be fixed if it is guaranteed to never become finite.

Specified by:

hasFixedSize in interface SizedIterable<T>

Overrides:

hasFixedSize in class TruncatedIterable<T>

isStatic

public boolean isStatic()

Always false: results of a lambda may be arbitrary.

Specified by:

isStatic in interface SizedIterable<T>

Overrides:

isStatic in class TruncatedIterable<T>

make

public static <T> FiniteSequenceIterable<T> make(T initial,
                                                 Lambda<? super T,? extends T> successor,
                                                 int size)

Call the constructor (allows T to be inferred)

makeSnapshot

public static <T> SnapshotIterable<T> makeSnapshot(T initial,
                                                   Lambda<? super T,? extends T> successor,
                                                   int size)

Create a FiniteSequenceIterable and wrap it in a SnapshotIterable, forcing immediate evaluation of the sequence.

makeIntegerSequence

public static FiniteSequenceIterable<Integer> makeIntegerSequence(int start,
                                                                  int end)

Create a simple sequence containing the numbers between start and end (inclusive). start may be less than or greater than end (or even equal to it); the resulting iterator will increment or decrement as necessary.

makeCopies

public static <T> FiniteSequenceIterable<T> makeCopies(T value,
                                                       int copies)

Create a sequence containing copies instances of the given value.