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Class com.sun.java.util.collections.AbstractSet
java.lang.Object
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+----com.sun.java.util.collections.AbstractCollection
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+----com.sun.java.util.collections.AbstractSet
- public abstract class AbstractSet
- extends AbstractCollection
- implements Set
This class provides a skeletal implementation of the Set
interface to minimize the effort required to implement this
interface.
The process of implementing a set by extending this class is identical
to that of implementing a Collection by extending AbstractCollection,
except that all of the methods and constructors in subclasses of this
class must obey the additional constraints imposed by the Set
interface (for instance, the add method must not permit addition of
multiple intances of an object to a set).
Note that this class does not override any of the implementations from
the AbstractCollection class. It merely adds implementations
for equals and hashCode.
- See Also:
- Collection, AbstractCollection, Set
-
AbstractSet()
- Sole constructor.
-
equals(Object)
- Compares the specified object with this set for equality.
-
hashCode()
- Returns the hash code value for this set.
AbstractSet
protected AbstractSet()
- Sole constructor. (For invocation by subclass constructors, typically
implicit.)
equals
public boolean equals(Object o)
- Compares the specified object with this set for equality. Returns
true if the given object is also a set, the two sets have
the same size, and every member of the given set is contained in
this set. This ensures that the equals method works
properly across different implementations of the Set
interface.
This implementation first checks if the specified object is this
set; if so it returns true. Then, it checks if the
specified object is a set whose size is identical to the size of
this set; if not, it it returns false. If so, it returns
containsAll((Collection) o).
- Parameters:
- o - Object to be compared for equality with this set.
- Returns:
- true if the specified object is equal to this set.
- Overrides:
- equals in class Object
hashCode
public int hashCode()
- Returns the hash code value for this set. The hash code of a set is
defined to be the sum of the hash codes of the elements in the set.
This ensures that s1.equals(s2) implies that
s1.hashCode()==s2.hashCode() for any two sets s1
and s2, as required by the general contract of
Object.hashCode.
This implementation enumerates over the set, calling the
hashCode method on each element in the collection, and
adding up the results.
- Returns:
- s the hash code value for this set.
- Overrides:
- hashCode in class Object
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