@GwtCompatible public abstract class ForwardingSet<E> extends ForwardingCollection<E> implements Set<E>
Warning: The methods of ForwardingSet
forward indiscriminately to the
methods of the delegate. For example, overriding ForwardingCollection.add(E)
alone will not change the
behavior of ForwardingCollection.addAll(java.util.Collection<? extends E>)
, which can lead to unexpected behavior. In this case, you should
override addAll
as well, either providing your own implementation, or delegating to the
provided standardAddAll
method.
default
method warning: This class does not forward calls to default
methods. Instead, it inherits their default implementations. When those implementations
invoke methods, they invoke methods on the ForwardingSet
.
The standard
methods are not guaranteed to be thread-safe, even when all of the
methods that they depend on are thread-safe.
Modifier | Constructor and Description |
---|---|
protected |
ForwardingSet()
Constructor for use by subclasses.
|
Modifier and Type | Method and Description |
---|---|
protected abstract Set<E> |
delegate()
Returns the backing delegate instance that methods are forwarded to.
|
boolean |
equals(@Nullable Object object)
Indicates whether some other object is "equal to" this one.
|
int |
hashCode()
Returns a hash code value for the object.
|
protected boolean |
standardEquals(@Nullable Object object)
A sensible definition of
equals(java.lang.Object) in terms of ForwardingCollection.size() and ForwardingCollection.containsAll(java.util.Collection<?>) . |
protected int |
standardHashCode()
A sensible definition of
hashCode() in terms of ForwardingCollection.iterator() . |
protected boolean |
standardRemoveAll(Collection<?> collection)
A sensible definition of
ForwardingCollection.removeAll(java.util.Collection<?>) in terms of ForwardingCollection.iterator() and ForwardingCollection.remove(java.lang.Object) . |
add, addAll, clear, contains, containsAll, isEmpty, iterator, remove, removeAll, retainAll, size, standardAddAll, standardClear, standardContains, standardContainsAll, standardIsEmpty, standardRemove, standardRetainAll, standardToArray, standardToArray, standardToString, toArray, toArray
toString
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
add, addAll, clear, contains, containsAll, isEmpty, iterator, remove, removeAll, retainAll, size, spliterator, toArray, toArray
parallelStream, removeIf, stream
protected ForwardingSet()
protected abstract Set<E> delegate()
ForwardingObject
delegate()
. Concrete subclasses override this method to supply the
instance being decorated.delegate
in class ForwardingCollection<E>
public boolean equals(@Nullable Object object)
java.lang.Object
The equals
method implements an equivalence relation
on non-null object references:
x
, x.equals(x)
should return
true
.
x
and y
, x.equals(y)
should return true
if and only if
y.equals(x)
returns true
.
x
, y
, and z
, if
x.equals(y)
returns true
and
y.equals(z)
returns true
, then
x.equals(z)
should return true
.
x
and y
, multiple invocations of
x.equals(y)
consistently return true
or consistently return false
, provided no
information used in equals
comparisons on the
objects is modified.
x
,
x.equals(null)
should return false
.
The equals
method for class Object
implements
the most discriminating possible equivalence relation on objects;
that is, for any non-null reference values x
and
y
, this method returns true
if and only
if x
and y
refer to the same object
(x == y
has the value true
).
Note that it is generally necessary to override the hashCode
method whenever this method is overridden, so as to maintain the
general contract for the hashCode
method, which states
that equal objects must have equal hash codes.
equals
in interface Collection<E>
equals
in interface Set<E>
equals
in class Object
object
- the reference object with which to compare.true
if this object is the same as the obj
argument; false
otherwise.Object.hashCode()
,
HashMap
public int hashCode()
java.lang.Object
HashMap
.
The general contract of hashCode
is:
hashCode
method
must consistently return the same integer, provided no information
used in equals
comparisons on the object is modified.
This integer need not remain consistent from one execution of an
application to another execution of the same application.
equals(Object)
method, then calling the hashCode
method on each of
the two objects must produce the same integer result.
Object.equals(java.lang.Object)
method, then calling the hashCode
method on each of the
two objects must produce distinct integer results. However, the
programmer should be aware that producing distinct integer results
for unequal objects may improve the performance of hash tables.
As much as is reasonably practical, the hashCode method defined by
class Object
does return distinct integers for distinct
objects. (This is typically implemented by converting the internal
address of the object into an integer, but this implementation
technique is not required by the
Java™ programming language.)
hashCode
in interface Collection<E>
hashCode
in interface Set<E>
hashCode
in class Object
Object.equals(java.lang.Object)
,
System.identityHashCode(java.lang.Object)
protected boolean standardRemoveAll(Collection<?> collection)
ForwardingCollection.removeAll(java.util.Collection<?>)
in terms of ForwardingCollection.iterator()
and ForwardingCollection.remove(java.lang.Object)
.
If you override iterator
or remove
, you may wish to override ForwardingCollection.removeAll(java.util.Collection<?>)
to forward to this implementation.standardRemoveAll
in class ForwardingCollection<E>
ForwardingCollection
version as of 12.0)protected boolean standardEquals(@Nullable Object object)
equals(java.lang.Object)
in terms of ForwardingCollection.size()
and ForwardingCollection.containsAll(java.util.Collection<?>)
. If
you override either of those methods, you may wish to override equals(java.lang.Object)
to forward to
this implementation.protected int standardHashCode()
hashCode()
in terms of ForwardingCollection.iterator()
. If you override
ForwardingCollection.iterator()
, you may wish to override equals(java.lang.Object)
to forward to this implementation.Copyright © 2010–2019. All rights reserved.