public abstract Class AbstractSet<E>

Overrides java.lang.Object.equals.

Implements java.util.Set.equals, java.util.Collection.equals.

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 returns false. If so, it returns containsAll((Collection) o).

Parameters

o:Object

object to be compared for equality with this set

Returns:boolean

true if the specified object is equal to this set

Overrides java.lang.Object.hashCode.

Implements java.util.Set.hashCode, java.util.Collection.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, where the hash code of a null element is defined to be zero. 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 iterates over the set, calling the hashCode method on each element in the set, and adding up the results.

Returns:int

the hash code value for this set

See Also

Object#equals(Object), Set#equals(Object)

Overrides java.util.AbstractCollection.removeAll.

Implements java.util.Set.removeAll, java.util.Collection.removeAll.

Removes from this set all of its elements that are contained in the specified collection (optional operation). If the specified collection is also a set, this operation effectively modifies this set so that its value is the asymmetric set difference of the two sets.

This implementation determines which is the smaller of this set and the specified collection, by invoking the size method on each. If this set has fewer elements, then the implementation iterates over this set, checking each element returned by the iterator in turn to see if it is contained in the specified collection. If it is so contained, it is removed from this set with the iterator's remove method. If the specified collection has fewer elements, then the implementation iterates over the specified collection, removing from this set each element returned by the iterator, using this set's remove method.

Note that this implementation will throw an UnsupportedOperationException if the iterator returned by the iterator method does not implement the remove method.

Parameters

c:Collection<?>

collection containing elements to be removed from this set

Returns:boolean

true if this set changed as a result of the call

Exceptions

UnsupportedOperationException:

if the removeAll operation is not supported by this set

ClassCastException:

if the class of an element of this set is incompatible with the specified collection (optional)

NullPointerException:

if this set contains a null element and the specified collection does not permit null elements (optional), or if the specified collection is null

See Also

remove(Object), contains(Object)