org.apache.myfaces.trinidad.util
Class CollectionUtils

java.lang.Object
  extended by org.apache.myfaces.trinidad.util.CollectionUtils

public final class CollectionUtils
extends Object

This class contains Collection utilities.


Nested Class Summary
protected static class CollectionUtils.AccessHookMap<K,V>
           
protected static class CollectionUtils.CompositeCollection<E>
          Note: Requires contents to be disjoint!
protected static class CollectionUtils.CompositeSet<E>
          Note: Requires contents to be disjoint!
protected static class CollectionUtils.DelegatingCollection<E>
           
protected static class CollectionUtils.DelegatingEntry<K,V>
           
protected static class CollectionUtils.DelegatingMap<K,V>
           
protected static class CollectionUtils.ExternalAccessHookMap<K,V>
           
protected static class CollectionUtils.LenientCompositeSet<E>
          Live composite set where both sets are allowed to be disjoint.
static interface CollectionUtils.MapMutationHooks<K,V>
          Interface for trapping mutations to a Map.
 
Method Summary
static
<T> ArrayList<T>
arrayList(Iterator<T> iterator)
          Returns an ArrayList containing all of the elements of the Iterator
static
<T> Set<T>
asSet(T... a)
          Returns a minimal Set containing the elements passed in.
static
<T> Set<T>
asUnmodifiableSet(T... a)
          Returns an unmodifiable Set containing the elements passed in.
static
<T> Set<T>
compositeSet(Set<T> primarySet, Set<T> secondarySet)
          Given two disjoint sets, returns a live composition of the two Sets that maintains the disjoint invariant.
protected static
<T> T[]
copyOf(T[] original, int newLength)
           
protected static
<T,U> T[]
copyOf(U[] original, int newLength, Class<? extends T[]> newType)
           
static
<T> Iterator<T>
emptyIterator()
          Returns an empty, unmodifiable, Iterator.
static
<T> ListIterator<T>
emptyListIterator()
          Returns an empty, unmodifiable, ListIterator.
static
<T> Queue<T>
emptyQueue()
          Returns an empty, unmodifiable, Serializable Queue.
static
<K,V> Map<K,V>
getCheckedSerializationMap(Map<K,V> map)
          Creates a Map that dynamically verifies that all keys and values added to it will succeed Serialization.
static
<K,V> Map<K,V>
getCheckedSerializationMap(Map<K,V> map, boolean requireSerializable)
          Creates a Map that dynamically verifies that all keys and values added to it will succeed Serialization.
static
<T> Collection<T>
getSerializableCollection(Collection<T> c)
          Returns a Collection based on the passed in Collection c, guaranteed to be Serializable.
static
<T> List<T>
getSerializableList(List<T> l)
          Returns a List based on the passed in List l, guaranteed to be Serializable.
static
<E> int
getUnionSize(Collection<? extends E> firstCollection, Collection<? extends E> secondCollection)
          Given two Collections, return the size of their union
static
<K,V> Map<K,V>
newMutationHookedMap(Map<K,V> map, CollectionUtils.MapMutationHooks<K,V> hooks)
          Creates a new Map that informs the MapMutationHooks of any direct mutations.
static
<T> List<T>
newSerializableList(List<T> l)
          Returns a List based on the passed in List l, guaranteed to be Serializable.
static
<T> Set<T>
overlappingCompositeSet(Set<T> primarySet, Set<T> secondarySet)
          Given two possibly overlapping sets, returns a live composition of the two Sets.
static
<T> T[]
toArray(Iterator<? extends T> iterator, Class<T> type)
          Returns an array containing all of the elements of the Iterator
static
<E extends Enum<E>>
Set<E>
unmodifiableCopyOfEnumSet(Set<E> s)
          Returns an unmodifiable versions of the Set of Enums.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Method Detail

arrayList

public static <T> ArrayList<T> arrayList(Iterator<T> iterator)
Returns an ArrayList containing all of the elements of the Iterator

Parameters:
iterator - Iterator to copy the contexts of
Returns:
an ArrayList containing a copy of the iterator contents

toArray

public static <T> T[] toArray(Iterator<? extends T> iterator,
                              Class<T> type)
Returns an array containing all of the elements of the Iterator

Parameters:
iterator - Iterator to copy the contexts of
Returns:
an array containing a copy of the iterator contents

emptyQueue

public static <T> Queue<T> emptyQueue()
Returns an empty, unmodifiable, Serializable Queue.

Returns:
an empty, unmodifiable, Serializable Queue.

emptyIterator

public static <T> Iterator<T> emptyIterator()
Returns an empty, unmodifiable, Iterator.

Returns:
an empty, unmodifiable, Iterator.

emptyListIterator

public static <T> ListIterator<T> emptyListIterator()
Returns an empty, unmodifiable, ListIterator.

Returns:
an empty, unmodifiable, ListIterator.

asSet

public static <T> Set<T> asSet(T... a)
Returns a minimal Set containing the elements passed in. There is no guarantee that the returned set is mutable or immutable.

Type Parameters:
T -
Parameters:
a - The elements to add to the Set
Returns:
A set containing the elements passed in.
See Also:
asUnmodifiableSet(T...)

asUnmodifiableSet

public static <T> Set<T> asUnmodifiableSet(T... a)
Returns an unmodifiable Set containing the elements passed in.

Type Parameters:
T -
Parameters:
a - The elements to add to the Set
Returns:
A set containing the elements passed in.
See Also:
asSet(T...)

unmodifiableCopyOfEnumSet

public static <E extends Enum<E>> Set<E> unmodifiableCopyOfEnumSet(Set<E> s)
Returns an unmodifiable versions of the Set of Enums. If the contents of the set are known to be unmodifiable by the caller in any way, the set itself will be retured, otherwise an unmodifiable copy of the Set will be returned.

Parameters:
s - Set to get the tamper-proof version of
Returns:
An unmodifiable tamper-proof version of the set

compositeSet

public static <T> Set<T> compositeSet(Set<T> primarySet,
                                      Set<T> secondarySet)
Given two disjoint sets, returns a live composition of the two Sets that maintains the disjoint invariant. If both Sets are Serializable, the returned implementation will be Serializable as well. The returned Set implementation is not thread safe.

Parameters:
primarySet - The Set that modifications will be applied to
secondarySet - The other Set. Modifications will be applied in response to changes to the primary set to ensure that the disjoint invariant is maintained
Returns:
The composition of the two disjoint Sets
Throws:
NullPointerException - of primarySet or secondarySet are null
See Also:
overlappingCompositeSet(java.util.Set, java.util.Set)

overlappingCompositeSet

public static <T> Set<T> overlappingCompositeSet(Set<T> primarySet,
                                                 Set<T> secondarySet)
Given two possibly overlapping sets, returns a live composition of the two Sets. If both Sets are Serializable, the returned implementation will be Serializable as well. The lack of the disjoint invariant makes operations such as calculating the size of the Set expensive. If the disjoint invariant can be guaranteed, compositeSet should be used instead. The returned Set implementation is not thread safe.

Parameters:
primarySet - The Set that modifications will be applied to
secondarySet - The other Set. If a removal is performed on the primarySet, it will also be applied to the secondarySet to ensure that the element is logically removed from the Set.
Returns:
The composition of the two possibly overallping Sets
Throws:
NullPointerException - of primarySet or secondarySet are null
See Also:
compositeSet(java.util.Set, java.util.Set)

getSerializableCollection

public static <T> Collection<T> getSerializableCollection(Collection<T> c)
Returns a Collection based on the passed in Collection c, guaranteed to be Serializable. If c is Serializable, c will be returned, otherwise, c will be wrapped in a Collection that implements Serializable and upon Serialization the contents of c will be copied into the result.

The results is very similar to creating a new ArrayList with the contents of c, but no wrapper is created unless necessary and the actual creation of the Serializable copy is deferred until Serialization occurs.

Parameters:
c - The Collection to get a Serializable version of
Returns:
A Serializable version of Collection c
See Also:
getSerializableList(java.util.List)

newSerializableList

public static <T> List<T> newSerializableList(List<T> l)
Returns a List based on the passed in List l, guaranteed to be Serializable. List l will be wrapped in a List that implements Serializable and upon Serialization the contents of l will be copied into the result.

If l implements RandomAccess, any returned List will also implement RandomAccess.

The results is very similar to creating a new ArrayList with the contents of l, but no wrapper is created unless necessary and the actual creation of the Serializable copy is deferred until Serialization occurs.

Code that calls List.subList() and needs the result to be Serializable should always use newSerializableList rather than getSerializableList because the java.util.Collections implementations of checkedList, unmodifiableList, and synchronizedList all lie and always implement Serializable, regardless of the serializability of their backing List.

Parameters:
l - The List to get a Serializable version of
Returns:
A Serializable version of List l
See Also:
getSerializableList(java.util.List), getSerializableCollection(java.util.Collection)

getSerializableList

public static <T> List<T> getSerializableList(List<T> l)
Returns a List based on the passed in List l, guaranteed to be Serializable. If l is Serializable, l will be returned, otherwise, l will be wrapped in a List that implements Serializable and upon Serialization the contents of l will be copied into the result.

If l implements RandomAccess, any returned List will also implement RandomAccess.

The results is very similar to creating a new ArrayList with the contents of l, but no wrapper is created unless necessary and the actual creation of the Serializable copy is deferred until Serialization occurs.

Code that calls List.subList() and needs the result to be Serializable should always use newSerializableList rather than getSerializableList because the java.util.Collections implementations of checkedList, unmodifiableList, and synchronizedList all lie and always implement Serializable, regardless of the serializability of their backing List.

Parameters:
l - The List to get a Serializable version of
Returns:
A Serializable version of List l
See Also:
newSerializableList(java.util.List), getSerializableCollection(java.util.Collection)

newMutationHookedMap

public static <K,V> Map<K,V> newMutationHookedMap(Map<K,V> map,
                                                  CollectionUtils.MapMutationHooks<K,V> hooks)
Creates a new Map that informs the MapMutationHooks of any direct mutations. Mutations to the underlying Map will not be caught. If the base map is Serializable, the returned Map will be Serializable

Type Parameters:
K - type of the keys of the Map
V - type of the values of the Map
Parameters:
map - Underlying map to trap mutations of
hooks - MapMutationHooks to inform of mutations to the returned Map
Returns:
a new Map that traps the mutations to the underlying Map
Throws:
NullPointerException - if map or hooks are null

getCheckedSerializationMap

public static <K,V> Map<K,V> getCheckedSerializationMap(Map<K,V> map)
Creates a Map that dynamically verifies that all keys and values added to it will succeed Serialization. The validations checks not only that the keys and values added to the Map implement Serializable, but that these instances will actually succeed Serialization.

This checking can be defeated by either modifying the backing map directly or by modifying an object added to the checked Map after adding it.

Parameters:
map - Map to wrap for Serialization validation
Returns:
Map where all modifications are checked to ensure that they will succeeed if serialized

getCheckedSerializationMap

public static <K,V> Map<K,V> getCheckedSerializationMap(Map<K,V> map,
                                                        boolean requireSerializable)
Creates a Map that dynamically verifies that all keys and values added to it will succeed Serialization. The validations checks not only that the keys and values added to the Map implement Serializable, but that these instances will actually succeed Serialization.

This checking can be defeated by either modifying the backing map directly or by modifying an object added to the checked Map after adding it.

Parameters:
map - Map to wrap for Serialization validation
requireSerializable - if true, require that all values in the map implement Serializable.
Returns:
Map where modifications are checked to ensure that they will succeeed if serialized

getUnionSize

public static <E> int getUnionSize(Collection<? extends E> firstCollection,
                                   Collection<? extends E> secondCollection)
Given two Collections, return the size of their union

Parameters:
firstCollection - The first collection. null is allowed.
secondCollection - The second collection. null is allowed.
Returns:

copyOf

protected static <T> T[] copyOf(T[] original,
                                int newLength)

copyOf

protected static <T,U> T[] copyOf(U[] original,
                                  int newLength,
                                  Class<? extends T[]> newType)


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