org.jppf.utils
Class CollectionUtils

java.lang.Object
  org.jppf.utils.CollectionUtils

public final class CollectionUtils
extends Object

This class provides a set of utility methods for manipulating and converting collections and arrays.

Author:

Laurent Cohen

Method Summary

static <T> T[]	concatArrays(T[]... arrays) Concatenate a set of array into a single array.
static <T,U> String	formatSizeMapInfo(String name, Map<T,List<U>> map) Format a string with size information about a map whose values are lists of elements.
static <T> List<T>	getAllElements(List<T> source, int start, int size) Generate a list that contains the specified number of elements of the specified list, starting at the specified position in the specified list.
static <T> List<T>	list(T... array) Convert an array into a List.
static <T,U> void	putInListMap(T key, U value, Map<T,List<U>> map) Add an element in a map whose values are lists of elements.
static <T,U> void	removeFromListMap(T key, U value, Map<T,List<U>> map) Remove an element from a map whose values are lists of elements.
static <T> Set<T>	set(T... array) Convert an array into a Set.
static <T,U> int	sizeOfListMap(Map<T,List<U>> map) Get the total number of elements in a map whose values are lists of elements.

Methods inherited from class java.lang.Object

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

Method Detail

set

public static <T> Set<T> set(T... array)

Convert an array into a Set.

Type Parameters:

T - the type of the elements in the array.

Parameters:

array - the array to convert.

Returns:

a set of elements with the same type as that of the array element type.

list

public static <T> List<T> list(T... array)

Convert an array into a List.

Type Parameters:

T - the type of the elements in the array.

Parameters:

array - the array to convert.

Returns:

a list of elements with the same type as that of the array element type.

concatArrays

public static <T> T[] concatArrays(T[]... arrays)

Concatenate a set of array into a single array.

Type Parameters:

T - the element type of the arrays to concatenate.

Parameters:

arrays - the arrays to concatenate.

Returns:

an array whose size is the sum of the sizes of all the input arrays, and whose elements are all the elements found in all the input arrays.

putInListMap

public static <T,U> void putInListMap(T key,
                                      U value,
                                      Map<T,List<U>> map)

Add an element in a map whose values are lists of elements.

Type Parameters:

T - the type of the keys in the map.

U - the type of the elements in the lists.

Parameters:

key - the key for the value to add.

value - the value to add.

map - the map in which ot add the key/value pair.

removeFromListMap

public static <T,U> void removeFromListMap(T key,
                                           U value,
                                           Map<T,List<U>> map)

Remove an element from a map whose values are lists of elements.

Type Parameters:

T - the type of the keys in the map.

U - the type of the elements in the lists.

Parameters:

key - the key for the value to remove.

value - the value to remove.

map - the map from which to remove the key/value pair.

sizeOfListMap

public static <T,U> int sizeOfListMap(Map<T,List<U>> map)

Get the total number of elements in a map whose values are lists of elements.

Type Parameters:

T - the type of the keys in the map.

U - the type of the elements in the lists.

Parameters:

map - the map of which to get the size.

Returns:

the size of the map as an int value.

formatSizeMapInfo

public static <T,U> String formatSizeMapInfo(String name,
                                             Map<T,List<U>> map)

Format a string with size information about a map whose values are lists of elements.

Type Parameters:

T - the type of the keys in the map.

U - the type of the values in the map.

Parameters:

name - an arbitrary name given to the map.

map - the map from which to get size information.

Returns:

a string containing information about the number of elements in the map.

getAllElements

public static <T> List<T> getAllElements(List<T> source,
                                         int start,
                                         int size)

Generate a list that contains the specified number of elements of the specified list, starting at the specified position in the specified list.

Type Parameters:

T - the type of the elements in the list.

Parameters:

source - the list from which to get the elements.

start - the start position in the source list.

size - the number of elements to get from the source list.

Returns:

the resulting list.