java.util
Class Collections.UnmodifiableSortedSet

java.lang.Object
  java.util.Collections.UnmodifiableCollection
      java.util.Collections.UnmodifiableSet
          java.util.Collections.UnmodifiableSortedSet

All Implemented Interfaces:

Collection, Serializable, Set, SortedSet

Enclosing class:

Collections

static class Collections.UnmodifiableSortedSet

extends Collections.UnmodifiableSet

implements SortedSet, Serializable

See Also:

Serialized Form

Field Summary

(package private) Collection	c
private SortedSet	ss

Constructor Summary

(package private)

Collections.UnmodifiableSortedSet(SortedSet s)

Method Summary

boolean	add(Object o) Adds the specified element to this set if it is not already present (optional operation).
boolean	addAll(Collection coll) 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).
Comparator	comparator() Returns the comparator associated with this sorted set, or null if it uses its elements' natural ordering.
boolean	contains(Object o) Returns true if this set contains the specified element.
boolean	containsAll(Collection coll) Returns true if this set contains all of the elements of the specified collection.
boolean	equals(Object o) Compares the specified object with this set for equality.
Object	first() Returns the first (lowest) element currently in this sorted set.
int	hashCode() Returns the hash code value for this set.
SortedSet	headSet(Object toElement) Returns a view of the portion of this sorted set whose elements are strictly less than toElement.
boolean	isEmpty() Returns true if this set contains no elements.
Iterator	iterator() Returns an iterator over the elements in this set.
Object	last() Returns the last (highest) element currently in this sorted set.
boolean	remove(Object o) Removes the specified element from this set if it is present (optional operation).
boolean	removeAll(Collection coll) Removes from this set all of its elements that are contained in the specified collection (optional operation).
boolean	retainAll(Collection coll) 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).
SortedSet	subSet(Object fromElement, Object toElement) Returns a view of the portion of this sorted set whose elements range from fromElement, inclusive, to toElement, exclusive.
SortedSet	tailSet(Object fromElement) Returns a view of the portion of this sorted set whose elements are greater than or equal to fromElement.
Object[]	toArray() Returns an array containing all of the elements in this set.
Object[]	toArray(Object[] 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.
String	toString() Returns a string representation of the object.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Set

add, addAll, clear, contains, containsAll, equals, hashCode, isEmpty, iterator, remove, removeAll, retainAll, size, toArray, toArray

Field Detail

ss

private SortedSet ss

c

Collection c

Constructor Detail

Collections.UnmodifiableSortedSet

Collections.UnmodifiableSortedSet(SortedSet s)

Method Detail

comparator

public Comparator comparator()

Description copied from interface: SortedSet

Returns the comparator associated with this sorted set, or null if it uses its elements' natural ordering.

Specified by:

comparator in interface SortedSet

Returns:

the comparator associated with this sorted set, or null if it uses its elements' natural ordering.

subSet

public SortedSet subSet(Object fromElement,
                        Object toElement)

Description copied from interface: SortedSet

Returns a view of the portion of this sorted set whose elements range from fromElement, inclusive, to toElement, exclusive. (If fromElement and toElement are equal, the returned sorted set is empty.) The returned sorted set is backed by this sorted set, so changes in the returned sorted set are reflected in this sorted set, and vice-versa. The returned sorted set supports all optional set operations that this sorted set supports.

The sorted set returned by this method will throw an IllegalArgumentException if the user attempts to insert a element outside the specified range.

Note: this method always returns a half-open range (which includes its low endpoint but not its high endpoint). If you need a closed range (which includes both endpoints), and the element type allows for calculation of the successor a given value, merely request the subrange from lowEndpoint to successor(highEndpoint). For example, suppose that s is a sorted set of strings. The following idiom obtains a view containing all of the strings in s from low to high, inclusive:

 SortedSet sub = s.subSet(low, high+"\0");
 

A similar technique can be used to generate an open range (which contains neither endpoint). The following idiom obtains a view containing all of the Strings in s from low to high, exclusive:

 SortedSet sub = s.subSet(low+"\0", high);
 

Specified by:

subSet in interface SortedSet

Parameters:

fromElement - low endpoint (inclusive) of the subSet.

toElement - high endpoint (exclusive) of the subSet.

Returns:

a view of the specified range within this sorted set.

headSet

public SortedSet headSet(Object toElement)

Description copied from interface: SortedSet

Returns a view of the portion of this sorted set whose elements are strictly less than toElement. The returned sorted set is backed by this sorted set, so changes in the returned sorted set are reflected in this sorted set, and vice-versa. The returned sorted set supports all optional set operations.

The sorted set returned by this method will throw an IllegalArgumentException if the user attempts to insert a element outside the specified range.

Note: this method always returns a view that does not contain its (high) endpoint. If you need a view that does contain this endpoint, and the element type allows for calculation of the successor a given value, merely request a headSet bounded by successor(highEndpoint). For example, suppose that s is a sorted set of strings. The following idiom obtains a view containing all of the strings in s that are less than or equal to high:

    SortedSet head = s.headSet(high+"\0");

Specified by:

headSet in interface SortedSet

Parameters:

toElement - high endpoint (exclusive) of the headSet.

Returns:

a view of the specified initial range of this sorted set.

tailSet

public SortedSet tailSet(Object fromElement)

Description copied from interface: SortedSet

Returns a view of the portion of this sorted set whose elements are greater than or equal to fromElement. The returned sorted set is backed by this sorted set, so changes in the returned sorted set are reflected in this sorted set, and vice-versa. The returned sorted set supports all optional set operations.

The sorted set returned by this method will throw an IllegalArgumentException if the user attempts to insert a element outside the specified range.

Note: this method always returns a view that contains its (low) endpoint. If you need a view that does not contain this endpoint, and the element type allows for calculation of the successor a given value, merely request a tailSet bounded by successor(lowEndpoint). For example, suppose that s is a sorted set of strings. The following idiom obtains a view containing all of the strings in s that are strictly greater than low:

    SortedSet tail = s.tailSet(low+"\0");

Specified by:

tailSet in interface SortedSet

Parameters:

fromElement - low endpoint (inclusive) of the tailSet.

Returns:

a view of the specified final range of this sorted set.

first

public Object first()

Description copied from interface: SortedSet

Returns the first (lowest) element currently in this sorted set.

Specified by:

first in interface SortedSet

Returns:

the first (lowest) element currently in this sorted set.

last

public Object last()

Description copied from interface: SortedSet

Returns the last (highest) element currently in this sorted set.

Specified by:

last in interface SortedSet

Returns:

the last (highest) element currently in this sorted set.

equals

public boolean equals(Object o)

Description copied from interface: Set

Compares the specified object with this set for equality. Returns true if the specified object is also a set, the two sets have the same size, and every member of the specified set is contained in this set (or equivalently, every member of this set is contained in the specified set). This definition ensures that the equals method works properly across different implementations of the set interface.

Specified by:

equals in interface Set

Overrides:

equals in class Object

Parameters:

o - the reference object with which to compare.

Returns:

true if this object is the same as the obj argument; false otherwise.

See Also:

Object.hashCode(), Hashtable

hashCode

public int hashCode()

Description copied from interface: Set

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 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 the Object.hashCode method.

Specified by:

hashCode in interface Set

Overrides:

hashCode in class Object

Returns:

a hash code value for this object.

See Also:

Object.equals(java.lang.Object), Hashtable

size

public int size()

Description copied from interface: Collection

Returns the number of elements in this collection. If this collection contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.

Specified by:

size in interface Collection

Returns:

the number of elements in this collection

isEmpty

public boolean isEmpty()

Description copied from interface: Collection

Returns true if this collection contains no elements.

Specified by:

isEmpty in interface Collection

Returns:

true if this collection contains no elements

contains

public boolean contains(Object o)

Description copied from interface: Collection

Returns true if this collection contains the specified element. More formally, returns true if and only if this collection contains at least one element e such that (o==null ? e==null : o.equals(e)).

Specified by:

contains in interface Collection

Parameters:

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

Returns:

true if this collection contains the specified element

toArray

public Object[] toArray()

Description copied from interface: Collection

Returns an array containing all of the elements in this collection. If the collection makes any guarantees as to what order its elements are returned by its iterator, this method must return the elements in the same order.

The returned array will be "safe" in that no references to it are maintained by this collection. (In other words, this method must allocate a new array even if this collection is backed by an array). The caller is thus free to modify the returned array.

This method acts as bridge between array-based and collection-based APIs.

Specified by:

toArray in interface Collection

Returns:

an array containing all of the elements in this collection

toArray

public Object[] toArray(Object[] a)

Description copied from interface: 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. If the collection fits in the specified array, it is returned therein. Otherwise, a new array is allocated with the runtime type of the specified array and the size of this collection.

If this collection fits in the specified array with room to spare (i.e., the array has more elements than this collection), the element in the array immediately following the end of the collection is set to null. This is useful in determining the length of this collection only if the caller knows that this collection does not contain any null elements.)

If this collection makes any guarantees as to what order its elements are returned by its iterator, this method must return the elements in the same order.

Like the toArray method, this method acts as bridge between array-based and collection-based APIs. Further, this method allows precise control over the runtime type of the output array, and may, under certain circumstances, be used to save allocation costs

Suppose l is a List known to contain only strings. The following code can be used to dump the list into a newly allocated array of String:

     String[] x = (String[]) v.toArray(new String[0]);
 

Note that toArray(new Object[0]) is identical in function to toArray().

Specified by:

toArray in interface Collection

Parameters:

a - the array into which the elements of this collection 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 collection

toString

public String toString()

Description copied from class: Object

Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

 getClass().getName() + '@' + Integer.toHexString(hashCode())
 

Overrides:

toString in class Object

Returns:

a string representation of the object.

iterator

public Iterator iterator()

Description copied from interface: Collection

Returns an iterator over the elements in this collection. There are no guarantees concerning the order in which the elements are returned (unless this collection is an instance of some class that provides a guarantee).

Specified by:

iterator in interface Collection

Returns:

an Iterator over the elements in this collection

add

public boolean add(Object o)

Description copied from interface: Collection

Ensures that this collection contains the specified element (optional operation). Returns true if this collection changed as a result of the call. (Returns false if this collection does not permit duplicates and already contains the specified element.)

Collections that support this operation may place limitations on what elements may be added to this collection. In particular, some collections will refuse to add null elements, and others will impose restrictions on the type of elements that may be added. Collection classes should clearly specify in their documentation any restrictions on what elements may be added.

If a collection refuses to add a particular element for any reason other than that it already contains the element, it must throw an exception (rather than returning false). This preserves the invariant that a collection always contains the specified element after this call returns.

Specified by:

add in interface Collection

Parameters:

o - element whose presence in this collection is to be ensured.

Returns:

true if this collection changed as a result of the call

remove

public boolean remove(Object o)

Description copied from interface: Collection

Removes a single instance of the specified element from this collection, if it is present (optional operation). More formally, removes an element e such that (o==null ? e==null : o.equals(e)), if this collection contains one or more such elements. Returns true if this collection contained the specified element (or equivalently, if this collection changed as a result of the call).

Specified by:

remove in interface Collection

Parameters:

o - element to be removed from this collection, if present.

Returns:

true if this collection changed as a result of the call

containsAll

public boolean containsAll(Collection coll)

Description copied from interface: Collection

Returns true if this collection contains all of the elements in the specified collection.

Specified by:

containsAll in interface Collection

Parameters:

coll - collection to be checked for containment in this collection.

Returns:

true if this collection contains all of the elements in the specified collection

See Also:

Collection.contains(Object)

addAll

public boolean addAll(Collection coll)

Description copied from interface: Collection

Adds all of the elements in the specified collection to this collection (optional operation). The behavior of this operation is undefined if the specified collection is modified while the operation is in progress. (This implies that the behavior of this call is undefined if the specified collection is this collection, and this collection is nonempty.)

Specified by:

addAll in interface Collection

Parameters:

coll - elements to be inserted into this collection.

Returns:

true if this collection changed as a result of the call

See Also:

Collection.add(Object)

removeAll

public boolean removeAll(Collection coll)

Description copied from interface: Collection

Removes all this collection's elements that are also contained in the specified collection (optional operation). After this call returns, this collection will contain no elements in common with the specified collection.

Specified by:

removeAll in interface Collection

Parameters:

coll - elements to be removed from this collection.

Returns:

true if this collection changed as a result of the call

See Also:

Collection.remove(Object), Collection.contains(Object)

retainAll

public boolean retainAll(Collection coll)

Description copied from interface: Collection

Retains only the elements in this collection that are contained in the specified collection (optional operation). In other words, removes from this collection all of its elements that are not contained in the specified collection.

Specified by:

retainAll in interface Collection

Parameters:

coll - elements to be retained in this collection.

Returns:

true if this collection changed as a result of the call

See Also:

Collection.remove(Object), Collection.contains(Object)

clear

public void clear()

Description copied from interface: Collection

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

Specified by:

clear in interface Collection