org.alfresco.util.collections

Class CollectionUtils

java.lang.Object

org.alfresco.util.collections.CollectionUtils

public abstract class CollectionUtils
extends java.lang.Object

Since:

4.0

Field Summary

Fields

Modifier and Type	Field and Description
static Function	TO_STRING_TRANSFORMER

Constructor Summary

Constructors

Constructor and Description
CollectionUtils()

Method Summary

Methods

Modifier and Type	Method and Description
static java.util.Set	asSet(java.lang.Class clazz, java.lang.Object[] objects) This utility method converts a vararg of Objects into a Set.
static Filter	containsFilter(java.util.Collection values)
static java.util.List	filter(java.util.Collection values, Function filter) Returns a filtered List of values.
static java.util.Map	filterKeys(java.util.Map map, Function filter) This method can be used to filter a Map.
static java.lang.Object	findFirst(java.util.Collection values, Function acceptor) Finds the first value for which acceptor returns true.
static java.util.List	flatten(java.util.Collection values)
static boolean	isEmpty(java.util.Collection items)
static java.util.List	nullSafeAppend(java.util.List first, java.util.List second) This method joins two lists returning the a single list consisting of the first followed by the second.
static java.util.List	nullSafeAppend(java.util.List first, java.util.List second, boolean emptyResultIsNull) This method joins two lists returning the a single list consisting of the first followed by the second.
static java.util.Map	nullSafeMerge(java.util.Map first, java.util.Map second) This method merges two maps returning the union of both maps.
static java.util.Map	nullSafeMerge(java.util.Map first, java.util.Map second, boolean emptyResultIsNull) This method merges two maps returning the union of both maps.
static java.util.Set	nullSafeMerge(java.util.Set first, java.util.Set second) This method merges two sets returning the union of both sets.
static java.util.Set	nullSafeMerge(java.util.Set first, java.util.Set second, boolean emptyResultIsNull) This method merges two sets returning the union of both sets.
static java.util.List	toListOfStrings(java.util.Collection values)
static java.util.List	transform(java.util.Collection values, Function transformer) Converts a Collection of values of type F to a Serializable List of values of type T.
static java.util.List	transform(Function transformer, java.lang.Object[] values) Converts a Collection of values of type F to a Serializable List of values of type T.
static java.util.Map	transform(java.util.Map map, Function transformer)
static java.util.List	transformFlat(java.util.Collection values, Function transformer)
static java.util.Map	transformToMap(java.util.Collection values, Function transformer)
static java.util.Set	unmodifiableSet(java.util.Collection values) Returns an immutable Serializable Set containing the values.
static java.util.Set	unmodifiableSet(java.lang.Object[] values) Returns an immutable Serializable Set containing the values.

Methods inherited from class java.lang.Object

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

Field Detail

TO_STRING_TRANSFORMER

public static final Function TO_STRING_TRANSFORMER

Constructor Detail

CollectionUtils

public CollectionUtils()

Method Detail

isEmpty

public static boolean isEmpty(java.util.Collection items)

nullSafeMerge

public static java.util.Set nullSafeMerge(java.util.Set first,
                          java.util.Set second)

This method merges two sets returning the union of both sets.

Parameters:

first - first set. can be null.

second - second set. can be null.

Returns:

the union of both sets. will not be null

nullSafeMerge

public static java.util.Set nullSafeMerge(java.util.Set first,
                          java.util.Set second,
                          boolean emptyResultIsNull)

This method merges two sets returning the union of both sets.

Parameters:

first - first set. can be null.

second - second set. can be null.

if - the result is empty, should we return null?

Returns:

the union of both sets or null.

nullSafeMerge

public static java.util.Map nullSafeMerge(java.util.Map first,
                          java.util.Map second)

This method merges two maps returning the union of both maps.

Parameters:

first - first map. can be null.

second - second map. can be null.

Returns:

the union of both maps. will not be null

nullSafeMerge

public static java.util.Map nullSafeMerge(java.util.Map first,
                          java.util.Map second,
                          boolean emptyResultIsNull)

This method merges two maps returning the union of both maps.

Parameters:

first - first map. can be null.

second - second map. can be null.

if - the result is empty, should we return null?

Returns:

the union of both maps, or null.

nullSafeAppend

public static java.util.List nullSafeAppend(java.util.List first,
                            java.util.List second)

This method joins two lists returning the a single list consisting of the first followed by the second.

Parameters:

first - first list. can be null.

second - second list. can be null.

Returns:

the concatenation of both lists. will not be null

nullSafeAppend

public static java.util.List nullSafeAppend(java.util.List first,
                            java.util.List second,
                            boolean emptyResultIsNull)

This method joins two lists returning the a single list consisting of the first followed by the second.

Parameters:

first - first list. can be null.

second - second list. can be null.

emptyResultIsNull - if the result is empty, should we return null?

Returns:

the concatenation of both lists or null

transform

public static java.util.List transform(java.util.Collection values,
                       Function transformer)

Converts a Collection of values of type F to a Serializable List of values of type T. Filters out all values converted to null.

Parameters:

values - the values to convert.

transformer - Used to convert values.

Returns:

transform

public static java.util.List transform(Function transformer,
                       java.lang.Object[] values)

Converts a Collection of values of type F to a Serializable List of values of type T. Filters out all values converted to null.

Parameters:

values - the values to convert.

transformer - Used to convert values.

Returns:

toListOfStrings

public static java.util.List toListOfStrings(java.util.Collection values)

asSet

public static java.util.Set asSet(java.lang.Class clazz,
                  java.lang.Object[] objects)

This utility method converts a vararg of Objects into a Set.

Parameters:

clazz - the Set type to return.

objects - the objects to be added to the set

Returns:

a Set of objects (any equal objects will of course not be duplicated)

Throws:

java.lang.ClassCastException - if any of the supplied objects are not of type T.

filter

public static java.util.List filter(java.util.Collection values,
                    Function filter)

Returns a filtered List of values. Only values for which filter.apply(T) returns true are included in the List or returned values.

Parameters:

values - the Collection to be filtered.

filter - the Function used to filter the Collection.

Returns:

the filtered List of values.

flatten

public static java.util.List flatten(java.util.Collection values)

transformFlat

public static java.util.List transformFlat(java.util.Collection values,
                           Function transformer)

findFirst

public static java.lang.Object findFirst(java.util.Collection values,
                         Function acceptor)

Finds the first value for which acceptor returns true.

Parameters:

values -

acceptor -

Returns:

returns accepted value or null.

unmodifiableSet

public static java.util.Set unmodifiableSet(java.lang.Object[] values)

Returns an immutable Serializable Set containing the values.

Parameters:

values -

Returns:

unmodifiableSet

public static java.util.Set unmodifiableSet(java.util.Collection values)

Returns an immutable Serializable Set containing the values.

Parameters:

values -

Returns:

transformToMap

public static java.util.Map transformToMap(java.util.Collection values,
                           Function transformer)

Parameters:

entries -

function -

Returns:

filterKeys

public static java.util.Map filterKeys(java.util.Map map,
                       Function filter)

This method can be used to filter a Map. Any keys in the supplied map, for which the supplied filter function returns true, will be included in the resultant Map, else they will not.

Parameters:

map - the map whose entries are to be filtered.

filter - the filter function which is applied to the key.

Returns:

a filtered map.

transform

public static java.util.Map transform(java.util.Map map,
                      Function transformer)

containsFilter

public static Filter containsFilter(java.util.Collection values)