org.deegree.framework.util
Class CollectionUtils

java.lang.Object
  org.deegree.framework.util.CollectionUtils

public class CollectionUtils
extends java.lang.Object

CollectionUtils contains some functionality missing in Arrays and Collections.

Version:

$Revision: 20893 $, $Date: 2009-11-19 14:31:51 +0100 (Do, 19 Nov 2009) $

Author:

Andreas Schmitz, last edited by: $Author: aschmitz $

Nested Class Summary

static interface	CollectionUtils.Folder<T> Folder
static interface	CollectionUtils.Mapper<T,U> Mapper gives a name to a simple function.
static interface	CollectionUtils.Predicate<T> Predicate defines a boolean predicate function interface.

Field Summary

static CollectionUtils.Mapper<java.lang.String,java.lang.Object>

TOSTRINGS

Constructor Summary

CollectionUtils()

Method Summary

static java.util.LinkedList<java.lang.Integer>	asList(int[] vals)
static <T> java.lang.String	collectionToString(java.util.Collection<T> col, java.lang.String sep)
static <T> boolean	contains(java.util.Collection<T> col, T obj)
static <T> boolean	contains(T[] array, T obj)
static <T> boolean	containsAllEqual(java.util.Collection<T> col, java.util.Collection<T> other) Attention: runs in n*n
static <T> boolean	containsEqual(java.util.Collection<T> col, T obj)
static <T> java.util.LinkedList<T>	filter(java.util.Collection<T> col, CollectionUtils.Predicate<T> pred)
static <T> T	find(java.util.Collection<T> col, CollectionUtils.Predicate<T> pred)
static <T> T	find(T[] array, CollectionUtils.Predicate<T> pred)
static <T> T	fold(T identity, java.util.Collection<T> col, CollectionUtils.Folder<T> folder)
static <T> T	last(T[] ts)
static <T,U> java.util.LinkedList<T>	map(java.util.Collection<U> col, CollectionUtils.Mapper<T,U> mapper) Wraps a for loop and the creation of a new list.
static <T,U> java.util.LinkedList<T>	map(U[] col, CollectionUtils.Mapper<T,U> mapper) Wraps a for loop and the creation of a new list.
static <T,U> java.util.LinkedHashMap<T,U>	unzip(java.util.Collection<Pair<T,U>> col) Not quite zip...
static <T,U> java.util.LinkedList<Pair<T,U>>	zip(java.util.Map<T,U> map) Not quite unzip...

Methods inherited from class java.lang.Object

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

Field Detail

TOSTRINGS

public static final CollectionUtils.Mapper<java.lang.String,java.lang.Object> TOSTRINGS

Constructor Detail

CollectionUtils

public CollectionUtils()

Method Detail

collectionToString

public static <T> java.lang.String collectionToString(java.util.Collection<T> col,
                                                      java.lang.String sep)

Type Parameters:

T -

Parameters:

col - may not contain null values

sep - the separating string

Returns:

a comma separated list of #toString values

map

public static <T,U> java.util.LinkedList<T> map(U[] col,
                                                CollectionUtils.Mapper<T,U> mapper)

Wraps a for loop and the creation of a new list.

Type Parameters:

T -

U -

Parameters:

col -

mapper -

Returns:

a list where the mapper has been applied to each element in the map

map

public static <T,U> java.util.LinkedList<T> map(java.util.Collection<U> col,
                                                CollectionUtils.Mapper<T,U> mapper)

Wraps a for loop and the creation of a new list.

Type Parameters:

T -

U -

Parameters:

col -

mapper -

Returns:

a list where the mapper has been applied to each element in the map

contains

public static <T> boolean contains(T[] array,
                                   T obj)

Type Parameters:

T -

Parameters:

array -

obj -

Returns:

true, if the object is contained within the array

contains

public static <T> boolean contains(java.util.Collection<T> col,
                                   T obj)

Type Parameters:

T -

Parameters:

col -

obj -

Returns:

true, if the object is contained within the collection

containsEqual

public static <T> boolean containsEqual(java.util.Collection<T> col,
                                        T obj)

Type Parameters:

T -

Parameters:

col -

obj -

Returns:

true, if an equal object is contained

containsAllEqual

public static <T> boolean containsAllEqual(java.util.Collection<T> col,
                                           java.util.Collection<T> other)

Attention: runs in n*n

Type Parameters:

T -

Parameters:

col -

other -

Returns:

true, if all elements in col have an equal in other

find

public static <T> T find(T[] array,
                         CollectionUtils.Predicate<T> pred)

Type Parameters:

T -

Parameters:

array -

pred -

Returns:

the first object for which the predicate is true, or null

find

public static <T> T find(java.util.Collection<T> col,
                         CollectionUtils.Predicate<T> pred)

Type Parameters:

T -

Parameters:

col -

pred -

Returns:

the first object for which the predicate is true, or null

filter

public static <T> java.util.LinkedList<T> filter(java.util.Collection<T> col,
                                                 CollectionUtils.Predicate<T> pred)

Type Parameters:

T -

Parameters:

col -

pred -

Returns:

only those T, for which the pred is true

fold

public static <T> T fold(T identity,
                         java.util.Collection<T> col,
                         CollectionUtils.Folder<T> folder)

Type Parameters:

T -

Parameters:

identity -

col -

folder -

Returns:

the folded value

asList

public static java.util.LinkedList<java.lang.Integer> asList(int[] vals)

Parameters:

vals -

Returns:

the array as list

unzip

public static <T,U> java.util.LinkedHashMap<T,U> unzip(java.util.Collection<Pair<T,U>> col)

Not quite zip...

Type Parameters:

T -

U -

Parameters:

col -

Returns:

a map with the first pair components mapping to the second

zip

public static <T,U> java.util.LinkedList<Pair<T,U>> zip(java.util.Map<T,U> map)

Not quite unzip...

Type Parameters:

T -

U -

Parameters:

map -

Returns:

a list with the keys paired with their values

last

public static <T> T last(T[] ts)

Type Parameters:

T -

Parameters:

ts -

Returns:

the last element or null