com.rubecula.darwin.examples.travelingsalesman
Class CircularLinkedList<E>

java.lang.Object
  java.util.AbstractCollection<E>
      java.util.AbstractList<E>
          java.util.AbstractSequentialList<E>
              com.rubecula.darwin.examples.travelingsalesman.CircularLinkedList<E>

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, java.lang.Iterable<E>, java.util.Collection<E>, java.util.Deque<E>, java.util.List<E>, java.util.Queue<E>

Direct Known Subclasses:

Route

public class CircularLinkedList<E>
extends java.util.AbstractSequentialList<E>
implements java.util.Deque<E>, java.lang.Cloneable, java.io.Serializable

Author:

Robin Hillyard Based on java.util.LinkedList which I would prefer to extend but it's full of private classes.

See Also:

Serialized Form

Field Summary

Fields inherited from class java.util.AbstractList

modCount

Constructor Summary

CircularLinkedList()
Constructs an empty list.

CircularLinkedList(java.util.Collection<? extends E> c)
Constructs a list containing the elements of the specified collection, in the order they are returned by the collection's iterator.

Method Summary

boolean	add(E e) Appends the specified element to the end of this list.
void	add(int index, E element) Inserts the specified element at the specified position in this list.
boolean	addAll(java.util.Collection<? extends E> c) Appends all of the elements in the specified collection to the end of this list, in the order that they are returned by the specified collection's iterator.
boolean	addAll(int index, java.util.Collection<? extends E> c) Inserts all of the elements in the specified collection into this list, starting at the specified position.
void	addFirst(E e) Inserts the specified element at the beginning of this list.
void	addLast(E e) Appends the specified element to the end of this list.
void	clear() Removes all of the elements from this list.
java.lang.Object	clone() Returns a shallow copy of this LinkedList.
boolean	contains(java.lang.Object o) Returns true if this list contains the specified element.
java.util.Iterator<E>	descendingIterator()
E	element() Retrieves, but does not remove, the head (first element) of this list.
E	get(int index) Returns the element at the specified position in this list.
E	getFirst() Returns the first element in this list.
E	getLast() Returns the last element in this list.
int	indexOf(java.lang.Object o) Returns the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element.
int	lastIndexOf(java.lang.Object o) Returns the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element.
java.util.ListIterator<E>	listIterator(int index) Returns a list-iterator of the elements in this list (in proper sequence), starting at the specified position in the list.
boolean	offer(E e) Adds the specified element as the tail (last element) of this list.
boolean	offerFirst(E e) Inserts the specified element at the front of this list.
boolean	offerLast(E e) Inserts the specified element at the end of this list.
E	peek() Retrieves, but does not remove, the head (first element) of this list.
E	peekFirst() Retrieves, but does not remove, the first element of this list, or returns null if this list is empty.
E	peekLast() Retrieves, but does not remove, the last element of this list, or returns null if this list is empty.
E	poll() Retrieves and removes the head (first element) of this list
E	pollFirst() Retrieves and removes the first element of this list, or returns null if this list is empty.
E	pollLast() Retrieves and removes the last element of this list, or returns null if this list is empty.
E	pop() Pops an element from the stack represented by this list.
void	push(E e) Pushes an element onto the stack represented by this list.
E	remove() Retrieves and removes the head (first element) of this list.
E	remove(int index) Removes the element at the specified position in this list.
boolean	remove(java.lang.Object o) Removes the first occurrence of the specified element from this list, if it is present.
E	removeFirst() Removes and returns the first element from this list.
boolean	removeFirstOccurrence(java.lang.Object o) Removes the first occurrence of the specified element in this list (when traversing the list from head to tail).
E	removeLast() Removes and returns the last element from this list.
boolean	removeLastOccurrence(java.lang.Object o) Removes the last occurrence of the specified element in this list (when traversing the list from head to tail).
E	set(int index, E element) Replaces the element at the specified position in this list with the specified element.
int	size() Returns the number of elements in this list.
java.lang.Object[]	toArray() Returns an array containing all of the elements in this list in proper sequence (from first to last element).
<T> T[]	toArray(T[] a) Returns an array containing all of the elements in this list in proper sequence (from first to last element); the runtime type of the returned array is that of the specified array.
java.lang.String	toString()
static int	usefulModulo(int top, int bottom)

Methods inherited from class java.util.AbstractSequentialList

iterator

Methods inherited from class java.util.AbstractList

equals, hashCode, listIterator, removeRange, subList

Methods inherited from class java.util.AbstractCollection

containsAll, isEmpty, removeAll, retainAll

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Deque

iterator

Methods inherited from interface java.util.Collection

containsAll, equals, hashCode, isEmpty, removeAll, retainAll

Methods inherited from interface java.util.List

containsAll, isEmpty, removeAll, retainAll

Constructor Detail

CircularLinkedList

public CircularLinkedList()

Constructs an empty list.

CircularLinkedList

public CircularLinkedList(java.util.Collection<? extends E> c)

Constructs a list containing the elements of the specified collection, in the order they are returned by the collection's iterator.

Parameters:

c - the collection whose elements are to be placed into this list

Throws:

java.lang.NullPointerException - if the specified collection is null

Method Detail

usefulModulo

public static int usefulModulo(int top,
                               int bottom)

add

public boolean add(E e)

Appends the specified element to the end of this list.

This method is equivalent to addLast(E).

Specified by:

add in interface java.util.Collection<E>

Specified by:

add in interface java.util.Deque<E>

Specified by:

add in interface java.util.List<E>

Specified by:

add in interface java.util.Queue<E>

Overrides:

add in class java.util.AbstractList<E>

Parameters:

e - element to be appended to this list

Returns:

true (as specified by Collection.add(E))

add

public void add(int index,
                E element)

Inserts the specified element at the specified position in this list. Shifts the element currently at that position (if any) and any subsequent elements to the right (adds one to their indices).

Specified by:

add in interface java.util.List<E>

Overrides:

add in class java.util.AbstractSequentialList<E>

Parameters:

index - index at which the specified element is to be inserted

element - element to be inserted

Throws:

java.lang.IndexOutOfBoundsException

addAll

public boolean addAll(java.util.Collection<? extends E> c)

Appends all of the elements in the specified collection to the end of this list, in the order that they are returned by the specified collection's iterator. The behavior of this operation is undefined if the specified collection is modified while the operation is in progress. (Note that this will occur if the specified collection is this list, and it's nonempty.)

Specified by:

addAll in interface java.util.Collection<E>

Specified by:

addAll in interface java.util.List<E>

Overrides:

addAll in class java.util.AbstractCollection<E>

Parameters:

c - collection containing elements to be added to this list

Returns:

true if this list changed as a result of the call

Throws:

java.lang.NullPointerException - if the specified collection is null

addAll

public boolean addAll(int index,
                      java.util.Collection<? extends E> c)

Inserts all of the elements in the specified collection into this list, starting at the specified position. Shifts the element currently at that position (if any) and any subsequent elements to the right (increases their indices). The new elements will appear in the list in the order that they are returned by the specified collection's iterator.

Specified by:

addAll in interface java.util.List<E>

Overrides:

addAll in class java.util.AbstractSequentialList<E>

Parameters:

index - index at which to insert the first element from the specified collection

c - collection containing elements to be added to this list

Returns:

true if this list changed as a result of the call

Throws:

java.lang.IndexOutOfBoundsException

java.lang.NullPointerException - if the specified collection is null

addFirst

public void addFirst(E e)

Inserts the specified element at the beginning of this list.

Specified by:

addFirst in interface java.util.Deque<E>

Parameters:

e - the element to add

addLast

public void addLast(E e)

Appends the specified element to the end of this list.

This method is equivalent to add(E).

Specified by:

addLast in interface java.util.Deque<E>

Parameters:

e - the element to add

clear

public void clear()

Removes all of the elements from this list.

Specified by:

clear in interface java.util.Collection<E>

Specified by:

clear in interface java.util.List<E>

Overrides:

clear in class java.util.AbstractList<E>

clone

public java.lang.Object clone()

Returns a shallow copy of this LinkedList. (The elements themselves are not cloned.)

Overrides:

clone in class java.lang.Object

Returns:

a shallow copy of this LinkedList instance

contains

public boolean contains(java.lang.Object o)

Returns true if this list contains the specified element. More formally, returns true if and only if this list contains at least one element e such that (o==null ? e==null : o.equals(e)).

Specified by:

contains in interface java.util.Collection<E>

Specified by:

contains in interface java.util.Deque<E>

Specified by:

contains in interface java.util.List<E>

Overrides:

contains in class java.util.AbstractCollection<E>

Parameters:

o - element whose presence in this list is to be tested

Returns:

true if this list contains the specified element

descendingIterator

public java.util.Iterator<E> descendingIterator()

Specified by:

descendingIterator in interface java.util.Deque<E>

Since:

1.6

element

public E element()

Retrieves, but does not remove, the head (first element) of this list.

Specified by:

element in interface java.util.Deque<E>

Specified by:

element in interface java.util.Queue<E>

Returns:

the head of this list

Throws:

java.util.NoSuchElementException - if this list is empty

Since:

1.5

get

public E get(int index)

Returns the element at the specified position in this list.

Specified by:

get in interface java.util.List<E>

Overrides:

get in class java.util.AbstractSequentialList<E>

Parameters:

index - index of the element to return

Returns:

the element at the specified position in this list

Throws:

java.lang.IndexOutOfBoundsException

getFirst

public E getFirst()

Returns the first element in this list.

Specified by:

getFirst in interface java.util.Deque<E>

Returns:

the first element in this list

Throws:

java.util.NoSuchElementException - if this list is empty

getLast

public E getLast()

Returns the last element in this list.

Specified by:

getLast in interface java.util.Deque<E>

Returns:

the last element in this list

Throws:

java.util.NoSuchElementException - if this list is empty

indexOf

public int indexOf(java.lang.Object o)

Returns the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element. More formally, returns the lowest index i such that (o==null ? get(i)==null : o.equals(get(i))), or -1 if there is no such index.

Specified by:

indexOf in interface java.util.List<E>

Overrides:

indexOf in class java.util.AbstractList<E>

Parameters:

o - element to search for

Returns:

the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element

lastIndexOf

public int lastIndexOf(java.lang.Object o)

Returns the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element. More formally, returns the highest index i such that (o==null ? get(i)==null : o.equals(get(i))), or -1 if there is no such index.

Specified by:

lastIndexOf in interface java.util.List<E>

Overrides:

lastIndexOf in class java.util.AbstractList<E>

Parameters:

o - element to search for

Returns:

the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element

listIterator

public java.util.ListIterator<E> listIterator(int index)

Returns a list-iterator of the elements in this list (in proper sequence), starting at the specified position in the list. Obeys the general contract of List.listIterator(int).

The list-iterator is fail-fast: if the list is structurally modified at any time after the Iterator is created, in any way except through the list-iterator's own remove or add methods, the list-iterator will throw a ConcurrentModificationException. Thus, in the face of concurrent modification, the iterator fails quickly and cleanly, rather than risking arbitrary, non-deterministic behavior at an undetermined time in the future.

Specified by:

listIterator in interface java.util.List<E>

Specified by:

listIterator in class java.util.AbstractSequentialList<E>

Parameters:

index - index of the first element to be returned from the list-iterator (by a call to next)

Returns:

a ListIterator of the elements in this list (in proper sequence), starting at the specified position in the list

Throws:

java.lang.IndexOutOfBoundsException

See Also:

List.listIterator(int)

offer

public boolean offer(E e)

Adds the specified element as the tail (last element) of this list.

Specified by:

offer in interface java.util.Deque<E>

Specified by:

offer in interface java.util.Queue<E>

Parameters:

e - the element to add

Returns:

true (as specified by Queue.offer(E))

Since:

1.5

offerFirst

public boolean offerFirst(E e)

Inserts the specified element at the front of this list.

Specified by:

offerFirst in interface java.util.Deque<E>

Parameters:

e - the element to insert

Returns:

true (as specified by Deque.offerFirst(E))

Since:

1.6

offerLast

public boolean offerLast(E e)

Inserts the specified element at the end of this list.

Specified by:

offerLast in interface java.util.Deque<E>

Parameters:

e - the element to insert

Returns:

true (as specified by Deque.offerLast(E))

Since:

1.6

peek

public E peek()

Retrieves, but does not remove, the head (first element) of this list.

Specified by:

peek in interface java.util.Deque<E>

Specified by:

peek in interface java.util.Queue<E>

Returns:

the head of this list, or null if this list is empty

Since:

1.5

peekFirst

public E peekFirst()

Retrieves, but does not remove, the first element of this list, or returns null if this list is empty.

Specified by:

peekFirst in interface java.util.Deque<E>

Returns:

the first element of this list, or null if this list is empty

Since:

1.6

peekLast

public E peekLast()

Retrieves, but does not remove, the last element of this list, or returns null if this list is empty.

Specified by:

peekLast in interface java.util.Deque<E>

Returns:

the last element of this list, or null if this list is empty

Since:

1.6

poll

public E poll()

Retrieves and removes the head (first element) of this list

Specified by:

poll in interface java.util.Deque<E>

Specified by:

poll in interface java.util.Queue<E>

Returns:

the head of this list, or null if this list is empty

Since:

1.5

pollFirst

public E pollFirst()

Retrieves and removes the first element of this list, or returns null if this list is empty.

Specified by:

pollFirst in interface java.util.Deque<E>

Returns:

the first element of this list, or null if this list is empty

Since:

1.6

pollLast

public E pollLast()

Retrieves and removes the last element of this list, or returns null if this list is empty.

Specified by:

pollLast in interface java.util.Deque<E>

Returns:

the last element of this list, or null if this list is empty

Since:

1.6

pop

public E pop()

Pops an element from the stack represented by this list. In other words, removes and returns the first element of this list.

This method is equivalent to removeFirst().

Specified by:

pop in interface java.util.Deque<E>

Returns:

the element at the front of this list (which is the top of the stack represented by this list)

Throws:

java.util.NoSuchElementException - if this list is empty

Since:

1.6

push

public void push(E e)

Pushes an element onto the stack represented by this list. In other words, inserts the element at the front of this list.

This method is equivalent to addFirst(E).

Specified by:

push in interface java.util.Deque<E>

Parameters:

e - the element to push

Since:

1.6

remove

public E remove()

Retrieves and removes the head (first element) of this list.

Specified by:

remove in interface java.util.Deque<E>

Specified by:

remove in interface java.util.Queue<E>

Returns:

the head of this list

Throws:

java.util.NoSuchElementException - if this list is empty

Since:

1.5

remove

public E remove(int index)

Removes the element at the specified position in this list. Shifts any subsequent elements to the left (subtracts one from their indices). Returns the element that was removed from the list.

Specified by:

remove in interface java.util.List<E>

Overrides:

remove in class java.util.AbstractSequentialList<E>

Parameters:

index - the index of the element to be removed

Returns:

the element previously at the specified position

Throws:

java.lang.IndexOutOfBoundsException

remove

public boolean remove(java.lang.Object o)

Removes the first occurrence of the specified element from this list, if it is present. If this list does not contain the element, it is unchanged. More formally, removes the element with the lowest index i such that (o==null ? get(i)==null : o.equals(get(i))) (if such an element exists). Returns true if this list contained the specified element (or equivalently, if this list changed as a result of the call).

Specified by:

remove in interface java.util.Collection<E>

Specified by:

remove in interface java.util.Deque<E>

Specified by:

remove in interface java.util.List<E>

Overrides:

remove in class java.util.AbstractCollection<E>

Parameters:

o - element to be removed from this list, if present

Returns:

true if this list contained the specified element

removeFirst

public E removeFirst()

Removes and returns the first element from this list.

Specified by:

removeFirst in interface java.util.Deque<E>

Returns:

the first element from this list

Throws:

java.util.NoSuchElementException - if this list is empty

removeFirstOccurrence

public boolean removeFirstOccurrence(java.lang.Object o)

Removes the first occurrence of the specified element in this list (when traversing the list from head to tail). If the list does not contain the element, it is unchanged.

Specified by:

removeFirstOccurrence in interface java.util.Deque<E>

Parameters:

o - element to be removed from this list, if present

Returns:

true if the list contained the specified element

Since:

1.6

removeLast

public E removeLast()

Removes and returns the last element from this list.

Specified by:

removeLast in interface java.util.Deque<E>

Returns:

the last element from this list

Throws:

java.util.NoSuchElementException - if this list is empty

removeLastOccurrence

public boolean removeLastOccurrence(java.lang.Object o)

Removes the last occurrence of the specified element in this list (when traversing the list from head to tail). If the list does not contain the element, it is unchanged.

Specified by:

removeLastOccurrence in interface java.util.Deque<E>

Parameters:

o - element to be removed from this list, if present

Returns:

true if the list contained the specified element

Since:

1.6

set

public E set(int index,
             E element)

Replaces the element at the specified position in this list with the specified element.

Specified by:

set in interface java.util.List<E>

Overrides:

set in class java.util.AbstractSequentialList<E>

Parameters:

index - index of the element to replace

element - element to be stored at the specified position

Returns:

the element previously at the specified position

Throws:

java.lang.IndexOutOfBoundsException

size

public int size()

Returns the number of elements in this list.

Specified by:

size in interface java.util.Collection<E>

Specified by:

size in interface java.util.Deque<E>

Specified by:

size in interface java.util.List<E>

Specified by:

size in class java.util.AbstractCollection<E>

Returns:

the number of elements in this list

toArray

public java.lang.Object[] toArray()

Returns an array containing all of the elements in this list in proper sequence (from first to last element).

The returned array will be "safe" in that no references to it are maintained by this list. (In other words, this method must allocate a new array). The caller is thus free to modify the returned array.

This method acts as bridge between array-based and collection-based APIs.

Specified by:

toArray in interface java.util.Collection<E>

Specified by:

toArray in interface java.util.List<E>

Overrides:

toArray in class java.util.AbstractCollection<E>

Returns:

an array containing all of the elements in this list in proper sequence

toArray

public <T> T[] toArray(T[] a)

Returns an array containing all of the elements in this list in proper sequence (from first to last element); the runtime type of the returned array is that of the specified array. If the list fits in the specified array, it is returned therein. Otherwise, a new array is allocated with the runtime type of the specified array and the size of this list.

If the list fits in the specified array with room to spare (i.e., the array has more elements than the list), the element in the array immediately following the end of the list is set to null. (This is useful in determining the length of the list only if the caller knows that the list does not contain any null elements.)

Like the toArray() method, this method acts as bridge between array-based and collection-based APIs. Further, this method allows precise control over the runtime type of the output array, and may, under certain circumstances, be used to save allocation costs.

Suppose x is a list known to contain only strings. The following code can be used to dump the list into a newly allocated array of String:

 String[] y = x.toArray(new String[0]);
 

Note that toArray(new Object[0]) is identical in function to toArray().

Specified by:

toArray in interface java.util.Collection<E>

Specified by:

toArray in interface java.util.List<E>

Overrides:

toArray in class java.util.AbstractCollection<E>

Parameters:

a - the array into which the elements of the list are to be stored, if it is big enough; otherwise, a new array of the same runtime type is allocated for this purpose.

Returns:

an array containing the elements of the list

Throws:

java.lang.ArrayStoreException - if the runtime type of the specified array is not a supertype of the runtime type of every element in this list

java.lang.NullPointerException - if the specified array is null

toString

public java.lang.String toString()

Overrides:

toString in class java.util.AbstractCollection<E>

See Also:

AbstractCollection.toString()