com.ge.research.utils
Class CollectionUtils

java.lang.Object
  com.ge.research.utils.CollectionUtils

Direct Known Subclasses:

ListUtils

public class CollectionUtils

extends java.lang.Object

A utility class with common, useful methods for dealing with Collections.

Version:

$Revision: 1.1 $ $Date: 2006/08/11 00:17:39 $

Author:

garbiras

Created on:

Aug 20, 2002

Constructor Summary

CollectionUtils()

Method Summary

static boolean	allElementsOfType(java.util.Collection c, java.lang.Class type) Checks each entry in the Collection to see if the entry is assignable to the argument class type.
static void	moveItem(java.util.Collection c, int moveFrom, int moveTo) Moves the element in the collection c from the position moveFrom to the position moveTo, and preserves the order of the collection.
static void	moveItem(java.util.Collection c, java.lang.Object element, int moveTo) Moves the element in the collection c from its current position to the position moveTo, and preserves the order of the collection.
static void	moveItemAfter(java.util.Collection c, java.lang.Object elementToMove, java.lang.Object referenceElement) Moves the elementToMove and places it directly after the referenceElement in the collection c, and preserves the order of the collection.
static void	moveItemBefore(java.util.Collection c, java.lang.Object elementToMove, java.lang.Object referenceElement) Moves the elementToMove and places it directly before the referenceElement in the collection c, and preserves the order of the collection.
static void	moveItemToEnd(java.util.Collection c, int moveFrom) Moves the element in the collection c currently at position moveFrom to the end of the collection, and preserves the order of the collection.
static void	moveItemToEnd(java.util.Collection c, java.lang.Object element) Moves the element in the collection c to the end of the collection, and preserves the order of the collection.
static void	moveItemToStart(java.util.Collection c, int moveFrom) Moves the element in the collection c currently at position moveFrom to the beginning of the collection, and preserves the order of the collection.
static void	moveItemToStart(java.util.Collection c, java.lang.Object element) Moves the element in the collection c to the beginning of the collection, and preserves the order of the collection.
static void	orderItems(java.util.Collection c, boolean orderAscending) Orders the elements of the collection based upon the collection elements object types.
static void	removeDuplicates(java.util.Collection c) Eliminates duplicate elements from the colection, and only retains a single instance of each unique element.
static void	reverseOrder(java.util.Collection c) Reverses the order of the elements of the Collection.
static void	swapItems(java.util.Collection c, java.lang.Object elementOne, java.lang.Object elementTwo) Moves two elements of the collection such that each element occupies the others original position.

Methods inherited from class java.lang.Object

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

Constructor Detail

CollectionUtils

public CollectionUtils()

Method Detail

allElementsOfType

public static boolean allElementsOfType(java.util.Collection c,
                                        java.lang.Class type)

Checks each entry in the Collection to see if the entry is assignable to the argument class type.

Parameters:

c - the datastructure that extends Collection and contains the elements of interest

type - the Class type to check each entry in the Collection against, to see if the entries are an instance of that class or one of its subclasses.

Returns:

true if all entries are of the type specified, or if the Collection is null or empty; false otherwise

moveItem

public static void moveItem(java.util.Collection c,
                            int moveFrom,
                            int moveTo)

Moves the element in the collection c from the position moveFrom to the position moveTo, and preserves the order of the collection.

Parameters:

c - the datastructure that extends Collection and contains the elements of interest

moveFrom - the index within the collection the element to move currently resides at

moveTo - the index within the collection the element is to be moved to

moveItem

public static void moveItem(java.util.Collection c,
                            java.lang.Object element,
                            int moveTo)

Moves the element in the collection c from its current position to the position moveTo, and preserves the order of the collection.

Parameters:

c - the datastructure that extends Collection and contains the elements of interest

element - the collection element to move

moveTo - the index within the collection the element is to be moved to

moveItemAfter

public static void moveItemAfter(java.util.Collection c,
                                 java.lang.Object elementToMove,
                                 java.lang.Object referenceElement)

Moves the elementToMove and places it directly after the referenceElement in the collection c, and preserves the order of the collection.

Parameters:

c - the datastructure that extends Collection and contains the elements of interest

elementToMove - the element to move

referenceElement - the element that marks the position within the collection that the moving element should immediately follow

moveItemToStart

public static void moveItemToStart(java.util.Collection c,
                                   int moveFrom)

Moves the element in the collection c currently at position moveFrom to the beginning of the collection, and preserves the order of the collection.

Parameters:

c - the datastructure that extends Collection and contains the elements of interest

moveFrom - the index within the collection the element to move currently resides at

See Also:

moveItem(java.util.Collection, int, int)

moveItemBefore

public static void moveItemBefore(java.util.Collection c,
                                  java.lang.Object elementToMove,
                                  java.lang.Object referenceElement)

Moves the elementToMove and places it directly before the referenceElement in the collection c, and preserves the order of the collection.

Parameters:

c - the datastructure that extends Collection and contains the elements of interest

elementToMove - the element to move

referenceElement - the element that marks the position within the collection that the moving element should immediately precede

moveItemToEnd

public static void moveItemToEnd(java.util.Collection c,
                                 int moveFrom)

Moves the element in the collection c currently at position moveFrom to the end of the collection, and preserves the order of the collection.

Parameters:

c - the datastructure that extends Collection and contains the elements of interest

moveFrom - the index within the collection the element to move currently resides at

See Also:

moveItem(java.util.Collection, int, int)

moveItemToEnd

public static void moveItemToEnd(java.util.Collection c,
                                 java.lang.Object element)

Moves the element in the collection c to the end of the collection, and preserves the order of the collection.

Parameters:

c - the datastructure that extends Collection and contains the elements of interest

element - the element to move to the end of the collection

See Also:

moveItem(java.util.Collection, java.lang.Object, int)

moveItemToStart

public static void moveItemToStart(java.util.Collection c,
                                   java.lang.Object element)

Moves the element in the collection c to the beginning of the collection, and preserves the order of the collection.

Parameters:

c - the datastructure that extends Collection and contains the elements of interest

element - the element to move to the beginning of the collection

See Also:

moveItem(java.util.Collection, java.lang.Object, int)

orderItems

public static void orderItems(java.util.Collection c,
                              boolean orderAscending)

Orders the elements of the collection based upon the collection elements object types. The collection can be ordered ascending or descending depending on the value of the orderAscending parameter. Each element of the collection must be of the same type and must implement the Comparable interface. If the collection type is determined to be String, then an attempt is made to see if the Strings represent numbers, and if so the collection is sorted by the numerical values, otherwise by the lexigraphical values.

Parameters:

c - the datastructure that extends Collection and contains the elements of interest

orderAscending - true if the collection should be sorting in ASCending fashion; false if the collection should be sorted in DESCending fasion

removeDuplicates

public static void removeDuplicates(java.util.Collection c)

Eliminates duplicate elements from the colection, and only retains a single instance of each unique element. The element uniqueness is determined by using the Object.equals(java.lang.Object) method as the comparison operator.

Parameters:

c - the datastructure that extends Collection and contains the elements of interest

reverseOrder

public static void reverseOrder(java.util.Collection c)

Reverses the order of the elements of the Collection.

Parameters:

c - the datastructure that extends Collection and contains the elements of interest

swapItems

public static void swapItems(java.util.Collection c,
                             java.lang.Object elementOne,
                             java.lang.Object elementTwo)

Moves two elements of the collection such that each element occupies the others original position.

Parameters:

c - the datastructure that extends Collection and contains the elements of interest

elementOne - the first element to move. Its current position will be occupied by elementTwo after the swap is performed

elementTwo - the second element to move Its current position will be occupied by elementOne after the swap is performed