Class ListView<E>
- java.lang.Object
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- one.microstream.collections.ListView<E>
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- All Implemented Interfaces:
Iterable<E>
,CapacityCarrying
,ExtendedBag<E>
,ExtendedCollection<E>
,ExtendedList<E>
,ExtendedSequence<E>
,Sized
,XGettingBag<E>
,XGettingCollection<E>
,XGettingList<E>
,XGettingSequence<E>
,XIndexIterable<E>
,XIterable<E>
,XJoinable<E>
,Copyable
public class ListView<E> extends Object implements XGettingList<E>
Wrapper class that reduces the services provided by any wrappedXGettingList
to only those ofXGettingList
, effectively making the wrappedXGettingList
instance immutable (or read-only) if used through an instance of this class.All methods declared in
XGettingList
are transparently passed to the wrapped list.
All modifying methods declared inCollection
andList
(all variations of add~(), remove~() and retain~() as well as set() and clear()) immediately throw anUnsupportedOperationException
when called.This concept can be very useful if a class wants to provide public read access to an internal list without either the danger of the list being modified from the outside or the need to copy the whole list on every access.
This is one of many useful concepts that are missing in the JDK Collections Framework and thus so far lead to either inefficient or unneccessary verbose program code (or both).
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
ListView.OldListView<E>
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Nested classes/interfaces inherited from interface one.microstream.typing.Copyable
Copyable.Static
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Nested classes/interfaces inherited from interface one.microstream.collections.interfaces.ExtendedCollection
ExtendedCollection.Creator<E,C extends ExtendedCollection<E>>
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Nested classes/interfaces inherited from interface one.microstream.collections.types.XGettingCollection
XGettingCollection.Creator<E>
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Nested classes/interfaces inherited from interface one.microstream.collections.types.XGettingList
XGettingList.Factory<E>
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Nested classes/interfaces inherited from interface one.microstream.collections.types.XIterable
XIterable.Executor<E>
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Constructor Summary
Constructors Constructor Description ListView(XGettingList<E> list)
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Method Summary
Modifier and Type Method Description boolean
applies(Predicate<? super E> predicate)
E
at(long index)
boolean
contains(E element)
boolean
containsAll(XGettingCollection<? extends E> elements)
boolean
containsId(E element)
Special version of contains() that guarantees to use identity comparison (" == ") when searching for the given element regardless of the collection's internal logic.
This method has the same behavior asXGettingCollection.containsSearched(Predicate)
with aPredicate
implementation that checks for object identity.boolean
containsSearched(Predicate<? super E> predicate)
ListView<E>
copy()
Creates a true copy of this list which references th same elements in the same order as this list does at the time the method is called.<C extends Consumer<? super E>>
CcopySelection(C target, long... indices)
<C extends Consumer<? super E>>
CcopyTo(C target)
long
count(E element)
long
countBy(Predicate<? super E> predicate)
<C extends Consumer<? super E>>
Cdistinct(C target)
<C extends Consumer<? super E>>
Cdistinct(C target, Equalator<? super E> equalator)
Equalator<? super E>
equality()
boolean
equals(Object o)
Deprecated.boolean
equals(XGettingCollection<? extends E> samples, Equalator<? super E> equalator)
Returnstrue
if the passed collection is of the same type as this collection andthis.equalsContent(list, equalator)
yieldstrue
.boolean
equalsContent(XGettingCollection<? extends E> samples, Equalator<? super E> equalator)
Returnstrue
if all elements of this list and the passed list are sequentially equal as defined by the passed equalator.<C extends Consumer<? super E>>
Cexcept(XGettingCollection<? extends E> other, Equalator<? super E> equalator, C target)
<C extends Consumer<? super E>>
CfilterTo(C target, Predicate<? super E> predicate)
E
first()
E
get()
Gets the first element in the collection.int
hashCode()
Deprecated.boolean
hasVolatileElements()
Tells if this collection contains volatile elements.
An element is volatile, if it can become no longer reachable by the collection without being removed from the collection.XImmutableList<E>
immure()
Provides an instance of an immutable collection type with equal behavior and data as this instance.long
indexBy(Predicate<? super E> predicate)
long
indexOf(E element)
<C extends Consumer<? super E>>
Cintersect(XGettingCollection<? extends E> other, Equalator<? super E> equalator, C target)
boolean
isEmpty()
boolean
isFull()
Returns true if the current capacity cannot be increased any more.boolean
isSorted(Comparator<? super E> comparator)
<P extends Consumer<? super E>>
Piterate(P procedure)
<P extends IndexedAcceptor<? super E>>
PiterateIndexed(P procedure)
Iterator<E>
iterator()
<A> A
join(BiConsumer<? super E,? super A> joiner, A aggregate)
E
last()
long
lastIndexBy(Predicate<? super E> predicate)
long
lastIndexOf(E element)
ListIterator<E>
listIterator()
ListIterator<E>
listIterator(long index)
E
max(Comparator<? super E> comparator)
long
maximumCapacity()
Returns the maximum amount of elements this carrier instance can contain.
The actual value may be depend on the configuration of the concrete instance or may depend only on the implementation of the carrier (meaning it is constant for all instances of the implementation, e.g.long
maxIndex(Comparator<? super E> comparator)
E
min(Comparator<? super E> comparator)
long
minIndex(Comparator<? super E> comparator)
boolean
nullAllowed()
boolean
nullContained()
ListView.OldListView<E>
old()
E
peek()
E
poll()
XGettingList<E>
range(long fromIndex, long toIndex)
long
remainingCapacity()
Returns the amount of elements this carrier instance can collect before reaching its maximimum capacity.long
scan(Predicate<? super E> predicate)
Iterates through the collection and returns the index of the last element that the passedPredicate
applied to ("scanning").E
search(Predicate<? super E> predicate)
E
seek(E sample)
Returns the first contained element matching the passed sample as defined by the collection's equality logic or null, if no fitting element is contained.long
size()
Object[]
toArray()
E[]
toArray(Class<E> type)
ListView<E>
toReversed()
String
toString()
<C extends Consumer<? super E>>
Cunion(XGettingCollection<? extends E> other, Equalator<? super E> equalator, C target)
ListView<E>
view()
SubListView<E>
view(long lowIndex, long highIndex)
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Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
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Methods inherited from interface java.lang.Iterable
forEach, spliterator
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Methods inherited from interface one.microstream.collections.types.XGettingCollection
intSize
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Methods inherited from interface one.microstream.collections.types.XGettingSequence
hasIndex
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Constructor Detail
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ListView
public ListView(XGettingList<E> list)
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Method Detail
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immure
public XImmutableList<E> immure()
Description copied from interface:XGettingList
Provides an instance of an immutable collection type with equal behavior and data as this instance.If this instance already is of an immutable collection type, it returns itself.
- Specified by:
immure
in interfaceXGettingBag<E>
- Specified by:
immure
in interfaceXGettingCollection<E>
- Specified by:
immure
in interfaceXGettingList<E>
- Specified by:
immure
in interfaceXGettingSequence<E>
- Returns:
- an immutable copy of this collection instance.
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equality
public Equalator<? super E> equality()
- Specified by:
equality
in interfaceXGettingCollection<E>
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hasVolatileElements
public boolean hasVolatileElements()
Description copied from interface:XGettingCollection
Tells if this collection contains volatile elements.
An element is volatile, if it can become no longer reachable by the collection without being removed from the collection. Examples areWeakReference
ofSoftReference
or implementations of collection entries that remove the element contained in an entry by some means outside the collection.
Note thatWeakReference
instances that are added to a a simple (non-volatile) implementation of a collection do NOT make the collection volatile, as the elements themselves (the reference instances) are still strongly referenced.- Specified by:
hasVolatileElements
in interfaceExtendedCollection<E>
- Specified by:
hasVolatileElements
in interfaceXGettingCollection<E>
- Returns:
true
if the collection contains volatile elements.
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containsSearched
public boolean containsSearched(Predicate<? super E> predicate)
- Specified by:
containsSearched
in interfaceXGettingCollection<E>
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applies
public boolean applies(Predicate<? super E> predicate)
- Specified by:
applies
in interfaceXGettingCollection<E>
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nullAllowed
public boolean nullAllowed()
- Specified by:
nullAllowed
in interfaceExtendedCollection<E>
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nullContained
public boolean nullContained()
- Specified by:
nullContained
in interfaceXGettingCollection<E>
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containsAll
public boolean containsAll(XGettingCollection<? extends E> elements)
- Specified by:
containsAll
in interfaceXGettingCollection<E>
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contains
public boolean contains(E element)
- Specified by:
contains
in interfaceXGettingCollection<E>
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containsId
public boolean containsId(E element)
Description copied from interface:XGettingCollection
Special version of contains() that guarantees to use identity comparison (" == ") when searching for the given element regardless of the collection's internal logic.
This method has the same behavior asXGettingCollection.containsSearched(Predicate)
with aPredicate
implementation that checks for object identity. The only difference is a performance and usability advantage- Specified by:
containsId
in interfaceXGettingCollection<E>
- Parameters:
element
- the element to be searched in the collection by identity.- Returns:
- whether this collection contains exactely the given element.
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copy
public ListView<E> copy()
Description copied from interface:XGettingSequence
Creates a true copy of this list which references th same elements in the same order as this list does at the time the method is called. The elements themselves are NOT copied (no deep copying).
The type of the returned list is the same as of this list if possible (i.e.: a SubList can not meaningful return a true copy that references its elements but still is a SubList)- Specified by:
copy
in interfaceCopyable
- Specified by:
copy
in interfaceXGettingBag<E>
- Specified by:
copy
in interfaceXGettingCollection<E>
- Specified by:
copy
in interfaceXGettingList<E>
- Specified by:
copy
in interfaceXGettingSequence<E>
- Returns:
- a copy of this list
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filterTo
public <C extends Consumer<? super E>> C filterTo(C target, Predicate<? super E> predicate)
- Specified by:
filterTo
in interfaceXGettingCollection<E>
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copyTo
public <C extends Consumer<? super E>> C copyTo(C target)
- Specified by:
copyTo
in interfaceXGettingCollection<E>
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count
public long count(E element)
- Specified by:
count
in interfaceXGettingCollection<E>
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countBy
public long countBy(Predicate<? super E> predicate)
- Specified by:
countBy
in interfaceXGettingCollection<E>
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distinct
public <C extends Consumer<? super E>> C distinct(C target, Equalator<? super E> equalator)
- Specified by:
distinct
in interfaceXGettingCollection<E>
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distinct
public <C extends Consumer<? super E>> C distinct(C target)
- Specified by:
distinct
in interfaceXGettingCollection<E>
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equals
public boolean equals(XGettingCollection<? extends E> samples, Equalator<? super E> equalator)
Description copied from interface:XGettingCollection
Returnstrue
if the passed collection is of the same type as this collection andthis.equalsContent(list, equalator)
yieldstrue
.- Specified by:
equals
in interfaceXGettingCollection<E>
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equalsContent
public boolean equalsContent(XGettingCollection<? extends E> samples, Equalator<? super E> equalator)
Description copied from interface:XGettingCollection
Returnstrue
if all elements of this list and the passed list are sequentially equal as defined by the passed equalator.Note that for colletion types that don't have a defined order of elements, this method is hardly usable (as is
XGettingCollection.equals(Object)
for them as defined inCollection
). The core problem of comparing collections that have no defined order is that they aren't really reliably comparable to any other collection.- Specified by:
equalsContent
in interfaceXGettingCollection<E>
equalator
- the equalator to use to determine the equality of each element- Returns:
true
if this list is equal to the passed list, false otherwise
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except
public <C extends Consumer<? super E>> C except(XGettingCollection<? extends E> other, Equalator<? super E> equalator, C target)
- Specified by:
except
in interfaceXGettingCollection<E>
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join
public final <A> A join(BiConsumer<? super E,? super A> joiner, A aggregate)
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iterateIndexed
public final <P extends IndexedAcceptor<? super E>> P iterateIndexed(P procedure)
- Specified by:
iterateIndexed
in interfaceXIndexIterable<E>
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get
public E get()
Description copied from interface:XGettingSequence
Gets the first element in the collection. This is a parameterless alias vorat(0)
.first() is an alias for this method for consistency reasons with last()
.- Specified by:
get
in interfaceXGettingCollection<E>
- Specified by:
get
in interfaceXGettingSequence<E>
- Returns:
- the first element.
- See Also:
XGettingSequence.at(long)
,XGettingSequence.first()
,XGettingSequence.last()
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first
public E first()
- Specified by:
first
in interfaceXGettingSequence<E>
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last
public E last()
- Specified by:
last
in interfaceXGettingSequence<E>
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poll
public E poll()
- Specified by:
poll
in interfaceXGettingSequence<E>
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peek
public E peek()
- Specified by:
peek
in interfaceXGettingSequence<E>
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indexBy
public long indexBy(Predicate<? super E> predicate)
- Specified by:
indexBy
in interfaceXGettingSequence<E>
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indexOf
public long indexOf(E element)
- Specified by:
indexOf
in interfaceXGettingSequence<E>
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intersect
public <C extends Consumer<? super E>> C intersect(XGettingCollection<? extends E> other, Equalator<? super E> equalator, C target)
- Specified by:
intersect
in interfaceXGettingCollection<E>
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isSorted
public boolean isSorted(Comparator<? super E> comparator)
- Specified by:
isSorted
in interfaceXGettingSequence<E>
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lastIndexBy
public long lastIndexBy(Predicate<? super E> predicate)
- Specified by:
lastIndexBy
in interfaceXGettingSequence<E>
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lastIndexOf
public long lastIndexOf(E element)
- Specified by:
lastIndexOf
in interfaceXGettingSequence<E>
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max
public E max(Comparator<? super E> comparator)
- Specified by:
max
in interfaceXGettingCollection<E>
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maxIndex
public long maxIndex(Comparator<? super E> comparator)
- Specified by:
maxIndex
in interfaceXGettingSequence<E>
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min
public E min(Comparator<? super E> comparator)
- Specified by:
min
in interfaceXGettingCollection<E>
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minIndex
public long minIndex(Comparator<? super E> comparator)
- Specified by:
minIndex
in interfaceXGettingSequence<E>
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scan
public long scan(Predicate<? super E> predicate)
Description copied from interface:XGettingSequence
Iterates through the collection and returns the index of the last element that the passedPredicate
applied to ("scanning").- Specified by:
scan
in interfaceXGettingSequence<E>
- Returns:
- the index of the last positively tested element.
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seek
public E seek(E sample)
Description copied from interface:XGettingCollection
Returns the first contained element matching the passed sample as defined by the collection's equality logic or null, if no fitting element is contained. (For collections using referential equality, this method is basically just a variation ofXGettingCollection.contains(Object)
with a different return type. For collections with data-dependant equality, the returned element might be the same as the passed one or a data-wise equal one, depending on the content of the collection)- Specified by:
seek
in interfaceXGettingCollection<E>
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search
public E search(Predicate<? super E> predicate)
- Specified by:
search
in interfaceXGettingCollection<E>
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view
public ListView<E> view()
- Specified by:
view
in interfaceXGettingBag<E>
- Specified by:
view
in interfaceXGettingCollection<E>
- Specified by:
view
in interfaceXGettingList<E>
- Specified by:
view
in interfaceXGettingSequence<E>
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view
public SubListView<E> view(long lowIndex, long highIndex)
- Specified by:
view
in interfaceXGettingList<E>
- Specified by:
view
in interfaceXGettingSequence<E>
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range
public XGettingList<E> range(long fromIndex, long toIndex)
- Specified by:
range
in interfaceXGettingList<E>
- Specified by:
range
in interfaceXGettingSequence<E>
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toReversed
public ListView<E> toReversed()
- Specified by:
toReversed
in interfaceXGettingList<E>
- Specified by:
toReversed
in interfaceXGettingSequence<E>
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union
public <C extends Consumer<? super E>> C union(XGettingCollection<? extends E> other, Equalator<? super E> equalator, C target)
- Specified by:
union
in interfaceXGettingCollection<E>
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copySelection
public <C extends Consumer<? super E>> C copySelection(C target, long... indices)
- Specified by:
copySelection
in interfaceXGettingSequence<E>
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hashCode
@Deprecated public int hashCode()
Deprecated.- Specified by:
hashCode
in interfaceXGettingCollection<E>
- Overrides:
hashCode
in classObject
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equals
@Deprecated public boolean equals(Object o)
Deprecated.Description copied from interface:XGettingCollection
Performs an equality comparison according to the specification inCollection
.Note that it is this interface's author opinion that the whole concept of equals() in standard Java, especially in the collection implementations, is flawed.
The reason is because all different kinds of comparison types that actually depend on the situation have to be mixed up in a harcoded fashion in one method, from identity comparison over data indentity comparison to content comparison.
In order to get the right behavior in every situation, one has to distinct between different types of equality
This means several things:
1.) You can't just say for example an ArrayList is the "same" as a LinkedList just because they contain the same content.
There are different implementations for a good reason, so you have to distinct them when comparing. There are simple code examples which create massive misbehavior that will catastrophically ruin the runtime behavior of a programm due to this error in Java / JDK / Sun / whatever.
2.) You can't always determine equality of two collections by determining equality of each element asCollection
defines it.As a conclusion: don't use this method!
Be clear what type of comparison you really need, then use one of the following methods and proper comparators:
XGettingCollection.equals(XGettingCollection,Equalator)
XGettingCollection.equalsContent(XGettingCollection,Equalator)
- Specified by:
equals
in interfaceXGettingCollection<E>
- Overrides:
equals
in classObject
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at
public E at(long index)
- Specified by:
at
in interfaceXGettingSequence<E>
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size
public long size()
- Specified by:
size
in interfaceSized
- Specified by:
size
in interfaceXGettingCollection<E>
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maximumCapacity
public long maximumCapacity()
Description copied from interface:CapacityCarrying
Returns the maximum amount of elements this carrier instance can contain.
The actual value may be depend on the configuration of the concrete instance or may depend only on the implementation of the carrier (meaning it is constant for all instances of the implementation, e.g.Integer.MAX_VALUE
)- Specified by:
maximumCapacity
in interfaceCapacityCarrying
- Returns:
- the maximum amount of elements this carrier instance can contain.
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isFull
public boolean isFull()
Description copied from interface:CapacityCarrying
Returns true if the current capacity cannot be increased any more.- Specified by:
isFull
in interfaceCapacityCarrying
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remainingCapacity
public long remainingCapacity()
Description copied from interface:CapacityCarrying
Returns the amount of elements this carrier instance can collect before reaching its maximimum capacity.- Specified by:
remainingCapacity
in interfaceCapacityCarrying
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toArray
public Object[] toArray()
- Specified by:
toArray
in interfaceXGettingCollection<E>
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listIterator
public ListIterator<E> listIterator()
- Specified by:
listIterator
in interfaceXGettingList<E>
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listIterator
public ListIterator<E> listIterator(long index)
- Specified by:
listIterator
in interfaceXGettingList<E>
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old
public ListView.OldListView<E> old()
- Specified by:
old
in interfaceXGettingCollection<E>
- Specified by:
old
in interfaceXGettingList<E>
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