jadex.commons.collection

Class IdentityHashSet<T>

java.lang.Object

jadex.commons.collection.IdentityHashSet<T>

All Implemented Interfaces:

java.lang.Iterable<T>, java.util.Collection<T>, java.util.Set<T>

public class IdentityHashSet<T>
extends java.lang.Object
implements java.util.Set<T>

A set based on identity comparison.

Field Summary

Fields

Modifier and Type	Field and Description
protected java.util.Map<T,T>	map The backing map.

Constructor Summary

Constructors

Constructor and Description
IdentityHashSet() Create a new identity hash set.

Method Summary

Modifier and Type	Method and Description
boolean	add(T o) Adds the specified element to this set if it is not already present (optional operation).
boolean	addAll(java.util.Collection<? extends T> c) Adds all of the elements in the specified collection to this set if they're not already present (optional operation).
void	clear() Removes all of the elements from this set (optional operation).
boolean	contains(java.lang.Object o) Returns
boolean	containsAll(java.util.Collection<?> c) Returns
boolean	equals(java.lang.Object o) Compares the specified object with this set for equality.
int	hashCode() Returns the hash code value for this set.
boolean	isEmpty() Returns
java.util.Iterator<T>	iterator() Returns an iterator over the elements in this set.
boolean	remove(java.lang.Object o) Removes the specified element from this set if it is present (optional operation).
boolean	removeAll(java.util.Collection<?> c) Removes from this set all of its elements that are contained in the specified collection (optional operation).
boolean	retainAll(java.util.Collection<?> c) Retains only the elements in this set that are contained in the specified collection (optional operation).
int	size() Returns the number of elements in this set (its cardinality).
java.lang.Object[]	toArray() Returns an array containing all of the elements in this set.
<E> E[]	toArray(E[] a) Returns an array containing all of the elements in this set; the runtime type of the returned array is that of the specified array.
java.lang.String	toString() Create a string representation.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Set

spliterator

Methods inherited from interface java.util.Collection

parallelStream, removeIf, stream

Methods inherited from interface java.lang.Iterable

forEach

Field Detail

map

protected java.util.Map<T,T> map

The backing map.

Constructor Detail

IdentityHashSet

public IdentityHashSet()

Create a new identity hash set.

Method Detail

size

public int size()

Returns the number of elements in this set (its cardinality). If this set contains more than

Specified by:

size in interface java.util.Collection<T>

Specified by:

size in interface java.util.Set<T>

Returns:

the number of elements in this set (its cardinality).

isEmpty

public boolean isEmpty()

Returns

Specified by:

isEmpty in interface java.util.Collection<T>

Specified by:

isEmpty in interface java.util.Set<T>

Returns:

contains

public boolean contains(java.lang.Object o)

Returns e such that (o==null ? e==null : o.equals(e)).

Specified by:

contains in interface java.util.Collection<T>

Specified by:

contains in interface java.util.Set<T>

Parameters:

o - element whose presence in this set is to be tested.

Returns:

Throws:

java.lang.ClassCastException - if the type of the specified element is incompatible with this set (optional).

java.lang.NullPointerException - if the specified element is null and this set does not support null elements (optional).

iterator

public java.util.Iterator<T> iterator()

Returns an iterator over the elements in this set. The elements are returned in no particular order (unless this set is an instance of some class that provides a guarantee).

Specified by:

iterator in interface java.lang.Iterable<T>

Specified by:

iterator in interface java.util.Collection<T>

Specified by:

iterator in interface java.util.Set<T>

Returns:

an iterator over the elements in this set.

toArray

public java.lang.Object[] toArray()

Returns an array containing all of the elements in this set. Obeys the general contract of the

Specified by:

toArray in interface java.util.Collection<T>

Specified by:

toArray in interface java.util.Set<T>

Returns:

an array containing all of the elements in this set.

toArray

public <E> E[] toArray(E[] a)

Returns an array containing all of the elements in this set; the runtime type of the returned array is that of the specified array. Obeys the general contract of the

Specified by:

toArray in interface java.util.Collection<T>

Specified by:

toArray in interface java.util.Set<T>

Parameters:

a - the array into which the elements of this set are to be stored, if it is big enough; otherwise, a new array of the same runtime type is allocated for this purpose.

Returns:

an array containing the elements of this set.

Throws:

java.lang.ArrayStoreException - the runtime type of a is not a supertype of the runtime type of every element in this set.

java.lang.NullPointerException - if the specified array is

add

public boolean add(T o)

Adds the specified element to this set if it is not already present (optional operation). More formally, adds the specified element, o, to this set if this set contains no element e such that (o==null ? e==null : o.equals(e)). If this set already contains the specified element, the call leaves this set unchanged and returns

Specified by:

add in interface java.util.Collection<T>

Specified by:

add in interface java.util.Set<T>

Parameters:

o - element to be added to this set.

Returns:

Throws:

java.lang.UnsupportedOperationException - if the

java.lang.ClassCastException - if the class of the specified element prevents it from being added to this set.

java.lang.NullPointerException - if the specified element is null and this set does not support null elements.

java.lang.IllegalArgumentException - if some aspect of the specified element prevents it from being added to this set.

remove

public boolean remove(java.lang.Object o)

Removes the specified element from this set if it is present (optional operation). More formally, removes an element e such that (o==null ? e==null : o.equals(e)), if the set contains such an element. Returns

Specified by:

remove in interface java.util.Collection<T>

Specified by:

remove in interface java.util.Set<T>

Parameters:

o - object to be removed from this set, if present.

Returns:

true if the set contained the specified element.

Throws:

java.lang.ClassCastException - if the type of the specified element is incompatible with this set (optional).

java.lang.NullPointerException - if the specified element is null and this set does not support null elements (optional).

java.lang.UnsupportedOperationException - if the

containsAll

public boolean containsAll(java.util.Collection<?> c)

Returns

Specified by:

containsAll in interface java.util.Collection<T>

Specified by:

containsAll in interface java.util.Set<T>

Parameters:

c - collection to be checked for containment in this set.

Returns:

Throws:

java.lang.ClassCastException - if the types of one or more elements in the specified collection are incompatible with this set (optional).

java.lang.NullPointerException - if the specified collection contains one or more null elements and this set does not support null elements (optional).

java.lang.NullPointerException - if the specified collection is

See Also:

contains(Object)

addAll

public boolean addAll(java.util.Collection<? extends T> c)

Adds all of the elements in the specified collection to this set if they're not already present (optional operation). If the specified collection is also a set, the

Specified by:

addAll in interface java.util.Collection<T>

Specified by:

addAll in interface java.util.Set<T>

Parameters:

c - collection whose elements are to be added to this set.

Returns:

Throws:

java.lang.UnsupportedOperationException - if the

java.lang.ClassCastException - if the class of some element of the specified collection prevents it from being added to this set.

java.lang.NullPointerException - if the specified collection contains one or more null elements and this set does not support null elements, or if the specified collection is

java.lang.IllegalArgumentException - if some aspect of some element of the specified collection prevents it from being added to this set.

See Also:

add(Object)

retainAll

public boolean retainAll(java.util.Collection<?> c)

Retains only the elements in this set that are contained in the specified collection (optional operation). In other words, removes from this set all of its elements that are not contained in the specified collection. If the specified collection is also a set, this operation effectively modifies this set so that its value is the

Specified by:

retainAll in interface java.util.Collection<T>

Specified by:

retainAll in interface java.util.Set<T>

Parameters:

c - collection that defines which elements this set will retain.

Returns:

Throws:

java.lang.UnsupportedOperationException - if the

java.lang.ClassCastException - if the types of one or more elements in this set are incompatible with the specified collection (optional).

java.lang.NullPointerException - if this set contains a null element and the specified collection does not support null elements (optional).

java.lang.NullPointerException - if the specified collection is

See Also:

remove(Object)

removeAll

public boolean removeAll(java.util.Collection<?> c)

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

Specified by:

removeAll in interface java.util.Collection<T>

Specified by:

removeAll in interface java.util.Set<T>

Parameters:

c - collection that defines which elements will be removed from this set.

Returns:

Throws:

java.lang.UnsupportedOperationException - if the

java.lang.ClassCastException - if the types of one or more elements in this set are incompatible with the specified collection (optional).

java.lang.NullPointerException - if this set contains a null element and the specified collection does not support null elements (optional).

java.lang.NullPointerException - if the specified collection is

See Also:

remove(Object)

clear

public void clear()

Removes all of the elements from this set (optional operation). This set will be empty after this call returns (unless it throws an exception).

Specified by:

clear in interface java.util.Collection<T>

Specified by:

clear in interface java.util.Set<T>

Throws:

java.lang.UnsupportedOperationException - if the

equals

public boolean equals(java.lang.Object o)

Compares the specified object with this set for equality. Returns

Specified by:

equals in interface java.util.Collection<T>

Specified by:

equals in interface java.util.Set<T>

Overrides:

equals in class java.lang.Object

Parameters:

o - Object to be compared for equality with this set.

Returns:

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, where the hashcode of a s1.equals(s2) implies that s1.hashCode()==s2.hashCode() for any two sets s1 and s2, as required by the general contract of the

Specified by:

hashCode in interface java.util.Collection<T>

Specified by:

hashCode in interface java.util.Set<T>

Overrides:

hashCode in class java.lang.Object

Returns:

the hash code value for this set.

See Also:

Object.hashCode(), Object.equals(Object), Set.equals(Object)

toString

public java.lang.String toString()

Create a string representation.

Overrides:

toString in class java.lang.Object