java.util
Class AbstractSet<E>
- Collection<E>, Iterable<E>, Set<E>
An abstract implementation of Set to make it easier to create your own
implementations. In order to create a Set, subclass AbstractSet and
implement the same methods that are required for AbstractCollection
(although these methods must of course meet the requirements that Set puts
on them - specifically, no element may be in the set more than once). This
class simply provides implementations of equals() and hashCode() to fulfil
the requirements placed on them by the Set interface.
AbstractSet()- The main constructor, for use by subclasses.
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boolean | equals(Object o)- Tests whether the given object is equal to this Set.
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int | hashCode()- Returns a hash code for this Set.
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boolean | removeAll(Collection c)- Removes from this set all elements in the given collection (optional
operation).
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T[] toArray, add, addAll, clear, contains, containsAll, isEmpty, iterator, remove, removeAll, retainAll, size, toArray, toString |
clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait |
AbstractSet
protected AbstractSet()
The main constructor, for use by subclasses.
equals
public boolean equals(Object o)
Tests whether the given object is equal to this Set. This implementation
first checks whether this set is the given object, and returns
true if so. Otherwise, if o is a Set and is the same size as this one, it
returns the result of calling containsAll on the given Set. Otherwise, it
returns false.
- equals in interface Set<E>
- equals in interface Collection<E>
- equals in interface Object
o - the Object to be tested for equality with this Set
- true if the given object is equal to this Set
hashCode
public int hashCode()
Returns a hash code for this Set. The hash code of a Set is the sum of the
hash codes of all its elements, except that the hash code of null is
defined to be zero. This implementation obtains an Iterator over the Set,
and sums the results.
- hashCode in interface Set<E>
- hashCode in interface Collection<E>
- hashCode in interface Object
removeAll
public boolean removeAll(Collection c)
Removes from this set all elements in the given collection (optional
operation). This implementation uses size() to determine
the smaller collection. Then, if this set is smaller, it iterates
over the set, calling Iterator.remove if the collection contains
the element. If this set is larger, it iterates over the collection,
calling Set.remove for all elements in the collection. Note that
this operation will fail if a remove methods is not supported.
- removeAll in interface Set<E>
- removeAll in interface Collection<E>
- removeAll in interface AbstractCollection<E>
c - the collection of elements to remove
- true if the set was modified as a result
AbstractSet.java -- Abstract implementation of most of Set
Copyright (C) 1998, 2000, 2001, 2004, 2005
Free Software Foundation, Inc.
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