com.google.common.collect

Class ForwardingSortedSet<E>

java.lang.Object

com.google.common.collect.ForwardingObject

com.google.common.collect.ForwardingCollection<E>

com.google.common.collect.ForwardingSet<E>

com.google.common.collect.ForwardingSortedSet<E>

All Implemented Interfaces:

Iterable<E>, Collection<E>, Set<E>, SortedSet<E>

Direct Known Subclasses:

ForwardingNavigableSet

@GwtCompatible
public abstract class ForwardingSortedSet<E>
extends ForwardingSet<E>
implements SortedSet<E>

A sorted set which forwards all its method calls to another sorted set. Subclasses should override one or more methods to modify the behavior of the backing sorted set as desired per the decorator pattern.

Warning: The methods of ForwardingSortedSet forward indiscriminately to the methods of the delegate. For example, overriding ForwardingCollection.add(E) alone will not change the behavior of ForwardingCollection.addAll(java.util.Collection<? extends E>), which can lead to unexpected behavior. In this case, you should override addAll as well, either providing your own implementation, or delegating to the provided standardAddAll method.

Each of the standard methods, where appropriate, uses the set's comparator (or the natural ordering of the elements, if there is no comparator) to test element equality. As a result, if the comparator is not consistent with equals, some of the standard implementations may violate the Set contract.

The standard methods and the collection views they return are not guaranteed to be thread-safe, even when all of the methods that they depend on are thread-safe.

Since:

2.0 (imported from Google Collections Library)

Author:

Mike Bostock, Louis Wasserman

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	ForwardingSortedSet() Constructor for use by subclasses.

Method Summary

Methods

Modifier and Type	Method and Description
Comparator<? super E>	comparator() Returns the comparator used to order the elements in this set, or null if this set uses the natural ordering of its elements.
protected abstract SortedSet<E>	delegate() Returns the backing delegate instance that methods are forwarded to.
E	first() Returns the first (lowest) element currently in this set.
SortedSet<E>	headSet(E toElement) Returns a view of the portion of this set whose elements are strictly less than toElement.
E	last() Returns the last (highest) element currently in this set.
protected boolean	standardContains(Object object) A sensible definition of ForwardingCollection.contains(java.lang.Object) in terms of the first() method of tailSet(E).
protected boolean	standardRemove(Object object) A sensible definition of ForwardingCollection.remove(java.lang.Object) in terms of the iterator() method of tailSet(E).
protected SortedSet<E>	standardSubSet(E fromElement, E toElement) A sensible default implementation of subSet(Object, Object) in terms of headSet(Object) and tailSet(Object).
SortedSet<E>	subSet(E fromElement, E toElement) Returns a view of the portion of this set whose elements range from fromElement, inclusive, to toElement, exclusive.
SortedSet<E>	tailSet(E fromElement) Returns a view of the portion of this set whose elements are greater than or equal to fromElement.

Methods inherited from class com.google.common.collect.ForwardingSet

equals, hashCode, standardEquals, standardHashCode, standardRemoveAll

Methods inherited from class com.google.common.collect.ForwardingCollection

add, addAll, clear, contains, containsAll, isEmpty, iterator, remove, removeAll, retainAll, size, standardAddAll, standardClear, standardContainsAll, standardIsEmpty, standardRetainAll, standardToArray, standardToArray, standardToString, toArray, toArray

Methods inherited from class com.google.common.collect.ForwardingObject

toString

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

Constructor Detail

ForwardingSortedSet

protected ForwardingSortedSet()

Constructor for use by subclasses.

Method Detail

delegate

protected abstract SortedSet<E> delegate()

Description copied from class: ForwardingObject

Returns the backing delegate instance that methods are forwarded to. Abstract subclasses generally override this method with an abstract method that has a more specific return type, such as ForwardingSet.delegate(). Concrete subclasses override this method to supply the instance being decorated.

Specified by:

delegate in class ForwardingSet<E>

comparator

public Comparator<? super E> comparator()

Description copied from interface: java.util.SortedSet

Returns the comparator used to order the elements in this set, or null if this set uses the natural ordering of its elements.

Specified by:

comparator in interface SortedSet<E>

Returns:

the comparator used to order the elements in this set, or null if this set uses the natural ordering of its elements

first

public E first()

Description copied from interface: java.util.SortedSet

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

Specified by:

first in interface SortedSet<E>

Returns:

the first (lowest) element currently in this set

headSet

public SortedSet<E> headSet(E toElement)

Description copied from interface: java.util.SortedSet

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

The returned set will throw an IllegalArgumentException on an attempt to insert an element outside its range.

Specified by:

headSet in interface SortedSet<E>

Parameters:

toElement - high endpoint (exclusive) of the returned set

Returns:

a view of the portion of this set whose elements are strictly less than toElement

last

public E last()

Description copied from interface: java.util.SortedSet

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

Specified by:

last in interface SortedSet<E>

Returns:

the last (highest) element currently in this set

subSet

public SortedSet<E> subSet(E fromElement,
                  E toElement)

Description copied from interface: java.util.SortedSet

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

The returned set will throw an IllegalArgumentException on an attempt to insert an element outside its range.

Specified by:

subSet in interface SortedSet<E>

Parameters:

fromElement - low endpoint (inclusive) of the returned set

toElement - high endpoint (exclusive) of the returned set

Returns:

a view of the portion of this set whose elements range from fromElement, inclusive, to toElement, exclusive

tailSet

public SortedSet<E> tailSet(E fromElement)

Description copied from interface: java.util.SortedSet

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

The returned set will throw an IllegalArgumentException on an attempt to insert an element outside its range.

Specified by:

tailSet in interface SortedSet<E>

Parameters:

fromElement - low endpoint (inclusive) of the returned set

Returns:

a view of the portion of this set whose elements are greater than or equal to fromElement

standardContains

@Beta
protected boolean standardContains(@Nullable
                            Object object)

A sensible definition of ForwardingCollection.contains(java.lang.Object) in terms of the first() method of tailSet(E). If you override tailSet(E), you may wish to override ForwardingCollection.contains(java.lang.Object) to forward to this implementation.

Overrides:

standardContains in class ForwardingCollection<E>

Since:

7.0

standardRemove

@Beta
protected boolean standardRemove(@Nullable
                          Object object)

A sensible definition of ForwardingCollection.remove(java.lang.Object) in terms of the iterator() method of tailSet(E). If you override tailSet(E), you may wish to override ForwardingCollection.remove(java.lang.Object) to forward to this implementation.

Overrides:

standardRemove in class ForwardingCollection<E>

Since:

7.0

standardSubSet

@Beta
protected SortedSet<E> standardSubSet(E fromElement,
                               E toElement)

A sensible default implementation of subSet(Object, Object) in terms of headSet(Object) and tailSet(Object). In some situations, you may wish to override subSet(Object, Object) to forward to this implementation.

Since:

7.0