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AI-generated Key Takeaways
AbstractSet is a skeletal Java class used as a base for creating new Set implementations, minimizing the work needed by inheriting functionalities from AbstractCollection.
It ensures all elements within the set are unique, adhering to the Set interface contract by providing concrete equals and hashCode methods.
Developers primarily use AbstractSet by extending it and implementing only the essential methods specific to their desired set implementation.
Key methods include equals for set comparison, hashCode for generating a hash code based on set elements, and removeAll for removing a collection of elements from the set.
While AbstractSet provides a foundation for set functionalities, developers should be aware of potential exceptions like UnsupportedOperationException, ClassCastException, and NullPointerException when working with its methods.
Hash table and linked list implementation of the Set interface,
with predictable iteration order.
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 instances 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.
Returns true if this collection contains all of the elements
in the specified collection.
This implementation iterates over the specified collection,
checking each element returned by the iterator in turn to see
if it's contained in this collection.
Removes all of this collection's elements that are also contained in the
specified collection (optional operation).
This implementation iterates over this collection, checking each
element returned by the iterator in turn to see if it's contained
in the specified collection.
Retains only the elements in this collection that are contained in the
specified collection (optional operation).
This implementation iterates over this collection, checking each
element returned by the iterator in turn to see if it's contained
in the specified collection.
Returns an array containing all of the elements in this collection;
the runtime type of the returned array is that of the specified array.
This implementation returns an array containing all the elements
returned by this collection's iterator in the same order, stored in
consecutive elements of the array, starting with index 0.
Returns an array containing all of the elements in this collection.
This implementation returns an array containing all the elements
returned by this collection's iterator, in the same order, stored in
consecutive elements of the array, starting with index 0.
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 to be compared for equality with this set
Returns
true if the specified object is equal to this set
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,
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.
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 containing elements to be removed from this set
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2024-07-10 UTC."],[],[]]
