edu.colorado.collections

Class DoubleLinkedSeq

java.lang.Object

edu.colorado.collections.DoubleLinkedSeq

All Implemented Interfaces:

java.lang.Cloneable

public class DoubleLinkedSeq
extends java.lang.Object
implements java.lang.Cloneable

This class is a homework assignment; A DoubleLinkedSeq is a collection of double numbers. The sequence can have a special "current element," which is specified and accessed through four methods that are not available in the sequence class (start, getCurrent, advance and isCurrent). Limitations: Beyond Int.MAX_VALUE elements, the size method does not work. Note: This file contains only blank implementations ("stubs") because this is a Programming Project for my students.

Constructor Summary

Constructors

Constructor and Description
DoubleLinkedSeq() Initialize an empty sequence.

Method Summary

Modifier and Type	Method and Description
void	addAfter(int element) Add a new element to this sequence, after the current element.
void	addAll(DoubleLinkedSeq addend) Place the contents of another sequence at the end of this sequence.
void	addBefore(int element) Add a new element to this sequence, before the current element.
void	advance() Move forward, so that the current element is now the next element in this sequence.
static DoubleLinkedSeq	catenation(DoubleLinkedSeq s1, DoubleLinkedSeq s2) Create a new sequence that contains all the elements from one sequence followed by another.
java.lang.Object	clone() Generate a copy of this sequence.
double	getCurrent() Accessor method to get the current element of this sequence.
double	isCurrent() Accessor method to determine whether this sequence has a specified current element that can be retrieved with the getCurrent method.
void	removeCurrent() Remove the current element from this sequence.
int	size() Determine the number of elements in this sequence.
void	start() Set the current element at the front of this sequence.

Methods inherited from class java.lang.Object

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

Constructor Detail

DoubleLinkedSeq

public DoubleLinkedSeq()

Initialize an empty sequence. Postcondition: This sequence is empty.

Method Detail

addAfter

public void addAfter(int element)

Add a new element to this sequence, after the current element.

Parameters:

element - the new element that is being added Postcondition: A new copy of the element has been added to this sequence. If there was a current element, then the new element is placed after the current element. If there was no current element, then the new element is placed at the end of the sequence. In all cases, the new element becomes the new current element of this sequence.

Throws:

java.lang.OutOfMemoryError - Indicates insufficient memory for a new node.

addBefore

public void addBefore(int element)

Add a new element to this sequence, before the current element.

Parameters:

element - the new element that is being added Postcondition: A new copy of the element has been added to this sequence. If there was a current element, then the new element is placed before the current element. If there was no current element, then the new element is placed at the start of the sequence. In all cases, the new element becomes the new current element of this sequence.

Throws:

java.lang.OutOfMemoryError - Indicates insufficient memory for a new node.

addAll

public void addAll(DoubleLinkedSeq addend)

Place the contents of another sequence at the end of this sequence.

Parameters:

addend - a sequence whose contents will be placed at the end of this sequence Precondition: The parameter, addend, is not null. Postcondition: The elements from addend have been placed at the end of this sequence. The current element of this sequence remains where it was, and the addend is also unchanged.

Throws:

java.lang.NullPointerException - Indicates that addend is null.

java.lang.OutOfMemoryError - Indicates insufficient memory to increase the size of this sequence.

advance

public void advance()

Move forward, so that the current element is now the next element in this sequence. Precondition: isCurrent() returns true. Postcondition: If the current element was already the end element of this sequence (with nothing after it), then there is no longer any current element. Otherwise, the new element is the element immediately after the original current element.

Throws:

java.lang.IllegalStateException - Indicates that there is no current element, so advance may not be called.

clone

public java.lang.Object clone()

Generate a copy of this sequence.

Overrides:

clone in class java.lang.Object

Returns:

The return value is a copy of this sequence. Subsequent changes to the copy will not affect the original, nor vice versa. Note that the return value must be type cast to a DoubleLinkedSeq before it can be used.

Throws:

java.lang.OutOfMemoryError - Indicates insufficient memory for creating the clone.

catenation

public static DoubleLinkedSeq catenation(DoubleLinkedSeq s1,
                                         DoubleLinkedSeq s2)

Create a new sequence that contains all the elements from one sequence followed by another.

Parameters:

s1 - the first of two sequences

s2 - the second of two sequences Precondition: Neither s1 nor s2 is null.

Returns:

a new sequence that has the elements of s1 followed by the elements of s2 (with no current element)

Throws:

java.lang.NullPointerException - Indicates that one of the arguments is null.

java.lang.OutOfMemoryError - Indicates insufficient memory for the new sequence.

getCurrent

public double getCurrent()

Accessor method to get the current element of this sequence. Precondition: isCurrent() returns true.

Returns:

the current capacity of this sequence

Throws:

java.lang.IllegalStateException - Indicates that there is no current element, so getCurrent may not be called.

isCurrent

public double isCurrent()

Accessor method to determine whether this sequence has a specified current element that can be retrieved with the getCurrent method.

Returns:

true (there is a current element) or false (there is no current element at the moment)

removeCurrent

public void removeCurrent()

Remove the current element from this sequence. Precondition: isCurrent() returns true. Postcondition: The current element has been removed from this sequence, and the following element (if there is one) is now the new current element. If there was no following element, then there is now no current element.

Throws:

java.lang.IllegalStateException - Indicates that there is no current element, so removeCurrent may not be called.

size

public int size()

Determine the number of elements in this sequence.

Returns:

the number of elements in this sequence

start

public void start()

Set the current element at the front of this sequence. Postcondition: The front element of this sequence is now the current element (but if this sequence has no elements at all, then there is no current element).