public final class CollectionUtils extends Object
Modifier and Type | Class and Description |
---|---|
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.
|
Modifier and Type | Method and Description |
---|---|
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>> |
unmodifiableCopyOfEnumSet(Set<E> s)
Returns an unmodifiable versions of the Set of Enums.
|
public static <T> ArrayList<T> arrayList(Iterator<T> iterator)
iterator
- Iterator to copy the contexts ofpublic static <T> T[] toArray(Iterator<? extends T> iterator, Class<T> type)
iterator
- Iterator to copy the contexts ofpublic static <T> Queue<T> emptyQueue()
public static <T> Iterator<T> emptyIterator()
public static <T> ListIterator<T> emptyListIterator()
public static <T> Set<T> asSet(T... a)
T
- a
- The elements to add to the SetasUnmodifiableSet(T...)
public static <T> Set<T> asUnmodifiableSet(T... a)
T
- a
- The elements to add to the SetasSet(T...)
public static <E extends Enum<E>> Set<E> unmodifiableCopyOfEnumSet(Set<E> s)
s
- Set to get the tamper-proof version ofpublic static <T> Set<T> compositeSet(Set<T> primarySet, Set<T> secondarySet)
primarySet
- The Set that modifications will be applied tosecondarySet
- The other Set. Modifications will be applied in response to changes
to the primary set to ensure that the disjoint invariant is maintainedNullPointerException
- of primarySet or secondarySet are null
overlappingCompositeSet(java.util.Set<T>, java.util.Set<T>)
public static <T> Set<T> overlappingCompositeSet(Set<T> primarySet, Set<T> secondarySet)
compositeSet
should be used instead.
The returned Set implementation is
not thread safe.primarySet
- The Set that modifications will be applied tosecondarySet
- 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.NullPointerException
- of primarySet or secondarySet are null
compositeSet(java.util.Set<T>, java.util.Set<T>)
public static <T> Collection<T> getSerializableCollection(Collection<T> c)
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.
c
- The Collection to get a Serializable version ofc
getSerializableList(java.util.List<T>)
public static <T> List<T> newSerializableList(List<T> l)
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.
l
- The List to get a Serializable version ofl
getSerializableList(java.util.List<T>)
,
getSerializableCollection(java.util.Collection<T>)
public static <T> List<T> getSerializableList(List<T> l)
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.
l
- The List to get a Serializable version ofl
newSerializableList(java.util.List<T>)
,
getSerializableCollection(java.util.Collection<T>)
public static <K,V> Map<K,V> newMutationHookedMap(Map<K,V> map, CollectionUtils.MapMutationHooks<K,V> hooks)
K
- type of the keys of the MapV
- type of the values of the Mapmap
- Underlying map to trap mutations ofhooks
- MapMutationHooks to inform of mutations to the returned MapNullPointerException
- if map or hooks are nullpublic static <K,V> Map<K,V> getCheckedSerializationMap(Map<K,V> map)
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.
map
- Map to wrap for Serialization validationpublic static <K,V> Map<K,V> getCheckedSerializationMap(Map<K,V> map, boolean requireSerializable)
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.
map
- Map to wrap for Serialization validationrequireSerializable
- if true
, require that all values in the map implement
Serializable.public static <E> int getUnionSize(Collection<? extends E> firstCollection, Collection<? extends E> secondCollection)
firstCollection
- The first collection. null
is allowed.secondCollection
- The second collection. null
is allowed.protected static <T> T[] copyOf(T[] original, int newLength)
protected static <T,U> T[] copyOf(U[] original, int newLength, Class<? extends T[]> newType)
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