Class SetView<E>
- All Implemented Interfaces:
Iterable<E>
,CapacityCarrying
,ExtendedCollection<E>
,Sized
,XGettingCollection<E>
,XGettingSet<E>
,XIterable<E>
,XJoinable<E>
,Copyable
public final class SetView<E> extends Object implements XGettingSet<E>
XGettingSet
to only those ofXGettingSet
, effectively making the wrapped XGettingSet
instance immutable (or read-only)
if used through an instance of this class.
All methods declared in XGettingSet
are transparently passed to the wrapped set.
All modifying methods declared in Collection
and Set
(all variations of add~(), remove~() and retain~() as well as set() and clear()) immediately throw an UnsupportedOperationException
when called.
This concept can be very useful if a class wants to provide public read access to an internal set without either the danger of the set being modified from the outside or the need to copy the whole set 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
SetView.OldSetView<E>
Nested classes/interfaces inherited from interface one.microstream.collections.types.XGettingSet
XGettingSet.Creator<E>
Nested classes/interfaces inherited from interface one.microstream.collections.types.XIterable
XIterable.Executor<E>
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Constructor Summary
Constructors Constructor Description SetView(XGettingSet<E> set)
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Method Summary
Modifier and Type Method Description boolean
applies(Predicate<? super E> predicate)
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)
SetView<E>
copy()
Creates a true copy of this collection which references the same elements as this collection does at the time the method is called.<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
get()
Gets one element from 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.XImmutableSet<E>
immure()
Provides an instance of an immutable collection type with equal behavior and data as this instance.<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.<P extends Consumer<? super E>>
Piterate(P procedure)
Iterator<E>
iterator()
<A> A
join(BiConsumer<? super E,? super A> joiner, A aggregate)
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.E
min(Comparator<? super E> comparator)
boolean
nullAllowed()
boolean
nullContained()
SetView.OldSetView<E>
old()
long
remainingCapacity()
Returns the amount of elements this carrier instance can collect before reaching its maximimum capacity.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)
<C extends Consumer<? super E>>
Cunion(XGettingCollection<? extends E> other, Equalator<? super E> equalator, C target)
SetView<E>
view()
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Constructor Details
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Method Details
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get
Description copied from interface:XGettingCollection
Gets one element from the collection. If the collection is not orderedXGettingSequence
, then it is undefined which element is returned. If the collection is ordered, the element at index 0 is returned.- Specified by:
get
in interfaceXGettingCollection<E>
- Returns:
- the first / any element.
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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
- Specified by:
containsSearched
in interfaceXGettingCollection<E>
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applies
- 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
- Specified by:
containsAll
in interfaceXGettingCollection<E>
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contains
- Specified by:
contains
in interfaceXGettingCollection<E>
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containsId
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
Description copied from interface:XGettingCollection
Creates a true copy of this collection which references the same elements as this collection does at the time the method is called. The elements themselves are NOT copied (no deep copying).
The type of the returned set is the same as of this list if possible.- Specified by:
copy
in interfaceCopyable
- Specified by:
copy
in interfaceXGettingCollection<E>
- Specified by:
copy
in interfaceXGettingSet<E>
- Returns:
- a copy of this list
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filterTo
- Specified by:
filterTo
in interfaceXGettingCollection<E>
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copyTo
- Specified by:
copyTo
in interfaceXGettingCollection<E>
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count
- Specified by:
count
in interfaceXGettingCollection<E>
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countBy
- Specified by:
countBy
in interfaceXGettingCollection<E>
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distinct
- Specified by:
distinct
in interfaceXGettingCollection<E>
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distinct
- Specified by:
distinct
in interfaceXGettingCollection<E>
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equals
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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iterate
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join
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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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max
- Specified by:
max
in interfaceXGettingCollection<E>
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min
- Specified by:
min
in interfaceXGettingCollection<E>
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seek
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
- Specified by:
search
in interfaceXGettingCollection<E>
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toArray
- Specified by:
toArray
in interfaceXGettingCollection<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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hashCode
Deprecated.- Specified by:
hashCode
in interfaceXGettingCollection<E>
- Overrides:
hashCode
in classObject
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equals
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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isEmpty
public boolean isEmpty() -
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
- Specified by:
toArray
in interfaceXGettingCollection<E>
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immure
Description copied from interface:XGettingCollection
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 interfaceXGettingCollection<E>
- Specified by:
immure
in interfaceXGettingSet<E>
- Returns:
- an immutable copy of this collection instance.
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old
- Specified by:
old
in interfaceXGettingCollection<E>
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iterator
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view
- Specified by:
view
in interfaceXGettingCollection<E>
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