--- jsr166/src/main/java/util/TreeSet.java 2005/05/03 02:52:07 1.10 +++ jsr166/src/main/java/util/TreeSet.java 2005/05/16 08:13:36 1.11 @@ -8,28 +8,27 @@ package java.util; /** - * This class implements the Set interface, backed by a - * TreeMap instance. This class guarantees that the sorted set will - * be in ascending element order, sorted according to the natural order - * of the elements (see Comparable), or by the comparator provided at - * set creation time, depending on which constructor is used.

+ * A {@link NavigableSet} implementation based on a {@link TreeMap}. + * The elements are ordered using their {@linkplain Comparable natural + * ordering}, or by a {@link Comparator} provided at set creation + * time, depending on which constructor is used. * - * This implementation provides guaranteed log(n) time cost for the basic - * operations (add, remove and contains).

+ *

This implementation provides guaranteed log(n) time cost for the basic + * operations (add, remove and contains). * - * Note that the ordering maintained by a set (whether or not an explicit + *

Note that the ordering maintained by a set (whether or not an explicit * comparator is provided) must be consistent with equals if it is to * correctly implement the Set interface. (See Comparable * or Comparator for a precise definition of consistent with * equals.) This is so because the Set interface is defined in * terms of the equals operation, but a TreeSet instance - * performs all key comparisons using its compareTo (or - * compare) method, so two keys that are deemed equal by this method + * performs all element comparisons using its compareTo (or + * compare) method, so two elements that are deemed equal by this method * are, from the standpoint of the set, equal. The behavior of a set * is well-defined even if its ordering is inconsistent with equals; it - * just fails to obey the general contract of the Set interface.

+ * just fails to obey the general contract of the Set interface. * - * Note that this implementation is not synchronized. If multiple + *

Note that this implementation is not synchronized. If multiple * threads access a set concurrently, and at least one of the threads modifies * the set, it must be synchronized externally. This is typically * accomplished by synchronizing on some object that naturally encapsulates @@ -37,12 +36,12 @@ package java.util; * Collections.synchronizedSet method. This is best done at creation * time, to prevent accidental unsynchronized access to the set:

  *     SortedSet s = Collections.synchronizedSortedSet(new TreeSet(...));
- * 

+ * * - * The Iterators returned by this class's iterator method are + *

The iterators returned by this class's iterator method are * fail-fast: if the set is modified at any time after the iterator is * created, in any way except through the iterator's own remove - * method, the iterator will throw a ConcurrentModificationException. + * method, the iterator will throw a {@link ConcurrentModificationException}. * Thus, in the face of concurrent modification, the iterator fails quickly * and cleanly, rather than risking arbitrary, non-deterministic behavior at * an undetermined time in the future. @@ -59,6 +58,8 @@ package java.util; * * Java Collections Framework. * + * @param the type of elements maintained by this set + * * @author Josh Bloch * @version %I%, %G% * @see Collection @@ -81,60 +82,62 @@ public class TreeSet private static final Object PRESENT = new Object(); /** - * Constructs a set backed by the specified sorted map. + * Constructs a set backed by the specified navigable map. */ private TreeSet(NavigableMap m) { this.m = m; } /** - * Constructs a new, empty set, sorted according to the elements' natural - * order. All elements inserted into the set must implement the - * Comparable interface. Furthermore, all such elements must be - * mutually comparable: e1.compareTo(e2) must not throw a + * Constructs a new, empty tree set, sorted according to the + * natural ordering of its elements. All elements inserted into + * the set must implement the {@link Comparable} interface. + * Furthermore, all such elements must be mutually + * comparable: e1.compareTo(e2) must not throw a * ClassCastException for any elements e1 and - * e2 in the set. If the user attempts to add an element to the - * set that violates this constraint (for example, the user attempts to - * add a string element to a set whose elements are integers), the - * add(Object) call will throw a ClassCastException. - * - * @see Comparable + * e2 in the set. If the user attempts to add an element + * to the set that violates this constraint (for example, the user + * attempts to add a string element to a set whose elements are + * integers), the add(Object) call will throw a + * ClassCastException. */ public TreeSet() { this(new TreeMap()); } /** - * Constructs a new, empty set, sorted according to the specified - * comparator. All elements inserted into the set must be mutually - * comparable by the specified comparator: comparator.compare(e1, - * e2) must not throw a ClassCastException for any elements - * e1 and e2 in the set. If the user attempts to add - * an element to the set that violates this constraint, the - * add(Object) call will throw a ClassCastException. - * - * @param c the comparator that will be used to sort this set. A - * null value indicates that the elements' natural - * ordering should be used. - */ - public TreeSet(Comparator c) { - this(new TreeMap(c)); + * Constructs a new, empty tree set, sorted according to the + * specified comparator. All elements inserted into the set must + * be mutually comparable by the specified comparator: + * comparator.compare(e1, e2) must not throw a + * ClassCastException for any elements e1 and + * e2 in the set. If the user attempts to add an element + * to the set that violates this constraint, the + * add(Object) call will throw a + * ClassCastException. + * + * @param comparator the comparator that will be used to order this set. + * If null, the {@linkplain Comparable natural + * ordering} of the elements will be used. + */ + public TreeSet(Comparator comparator) { + this(new TreeMap(comparator)); } /** - * Constructs a new set containing the elements in the specified - * collection, sorted according to the elements' natural order. - * All keys inserted into the set must implement the Comparable - * interface. Furthermore, all such keys must be mutually - * comparable: k1.compareTo(k2) must not throw a - * ClassCastException for any elements k1 and - * k2 in the set. - * - * @param c The elements that will comprise the new set. - * - * @throws ClassCastException if the keys in the specified collection are - * not comparable, or are not mutually comparable. - * @throws NullPointerException if the specified collection is null. + * Constructs a new tree set containing the elements in the + * specified collection, sorted according to the natural + * ordering of its elements. All elements inserted into the + * set must implement the {@link Comparable} interface. + * Furthermore, all such elements must be mutually + * comparable: e1.compareTo(e2) must not throw a + * ClassCastException for any elements e1 and + * e2 in the set. + * + * @param c collection whose elements will comprise the new set + * @throws ClassCastException if the elements in c are + * not {@link Comparable}, or are not mutually comparable + * @throws NullPointerException if the specified collection is null */ public TreeSet(Collection c) { this(); @@ -142,11 +145,11 @@ public class TreeSet } /** - * Constructs a new set containing the same elements as the specified - * sorted set, sorted according to the same ordering. + * Constructs a new tree set containing the same elements and + * using the same ordering as the specified sorted set. * - * @param s sorted set whose elements will comprise the new set. - * @throws NullPointerException if the specified sorted set is null. + * @param s sorted set whose elements will comprise the new set + * @throws NullPointerException if the specified sorted set is null */ public TreeSet(SortedSet s) { this(s.comparator()); @@ -157,17 +160,17 @@ public class TreeSet * Returns an iterator over the elements in this set. The elements * are returned in ascending order. * - * @return an iterator over the elements in this set. + * @return an iterator over the elements in this set */ public Iterator iterator() { - return m.keySet().iterator(); + return m.keySet().iterator(); } /** * Returns an iterator over the elements in this set. The elements * are returned in descending order. * - * @return an iterator over the elements in this set. + * @return an iterator over the elements in this set */ public Iterator descendingIterator() { return m.descendingKeySet().iterator(); @@ -176,7 +179,7 @@ public class TreeSet /** * Returns the number of elements in this set (its cardinality). * - * @return the number of elements in this set (its cardinality). + * @return the number of elements in this set (its cardinality) */ public int size() { return m.size(); @@ -185,7 +188,7 @@ public class TreeSet /** * Returns true if this set contains no elements. * - * @return true if this set contains no elements. + * @return true if this set contains no elements */ public boolean isEmpty() { return m.isEmpty(); @@ -194,14 +197,13 @@ public class TreeSet /** * Returns true if this set contains the specified element. * - * @param o the object to be checked for containment in this set. - * @return true if this set contains the specified element. - * + * @param o the object to be checked for containment in this set + * @return true if this set contains the specified element * @throws ClassCastException if the specified object cannot be compared - * with the elements currently in the set. - * @throws NullPointerException if o is null and this map - * uses natural ordering and is non-empty, or its comparator does - * not tolerate null keys. + * with the elements currently in the set + * @throws NullPointerException if the specified element is null and + * this set uses natural ordering and is non-empty, or its + * comparator does not permit null elements */ public boolean contains(Object o) { return m.containsKey(o); @@ -210,15 +212,14 @@ public class TreeSet /** * Adds the specified element to this set if it is not already present. * - * @param e element to be added to this set. + * @param e element to be added to this set * @return true if the set did not already contain the specified - * element. - * + * element * @throws ClassCastException if the specified object cannot be compared - * with the elements currently in the set. - * @throws NullPointerException if e is null and this map - * uses natural ordering and is non-empty, or its comparator does - * not tolerate null keys. + * with the elements currently in the set + * @throws NullPointerException if the specified element is null and + * this set uses natural ordering and is non-empty, or its + * comparator does not permit null elements */ public boolean add(E e) { return m.put(e, PRESENT)==null; @@ -227,14 +228,13 @@ public class TreeSet /** * Removes the specified element from this set if it is present. * - * @param o object to be removed from this set, if present. - * @return true if the set contained the specified element. - * + * @param o object to be removed from this set, if present + * @return true if the set contained the specified element * @throws ClassCastException if the specified object cannot be compared - * with the elements currently in the set. - * @throws NullPointerException if o is null and this map - * uses natural ordering and is non-empty, or its comparator does - * not tolerate null keys. + * with the elements currently in the set + * @throws NullPointerException if the specified element is null and + * this set uses natural ordering and is non-empty, or its + * comparator does not permit null elements */ public boolean remove(Object o) { return m.remove(o)==PRESENT; @@ -242,6 +242,7 @@ public class TreeSet /** * Removes all of the elements from this set. + * The set will be empty after this call returns. */ public void clear() { m.clear(); @@ -251,14 +252,12 @@ public class TreeSet * Adds all of the elements in the specified collection to this set. * * @param c elements to be added - * @return true if this set changed as a result of the call. - * + * @return true if this set changed as a result of the call * @throws ClassCastException if the elements provided cannot be compared - * with the elements currently in the set. - * @throws NullPointerException if the specified collection is - * null or if any element is null and this map - * uses natural ordering, or its comparator does not tolerate - * null keys. + * with the elements currently in the set + * @throws NullPointerException if the specified collection is null or + * if any element is null and this set uses natural ordering, or + * its comparator does not permit null elements */ public boolean addAll(Collection c) { // Use linear-time version if applicable @@ -278,227 +277,99 @@ public class TreeSet } /** - * 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 navigable set is empty.) The returned - * navigable set is backed by this set, so changes in the returned - * navigable set are reflected in this set, and vice-versa. The - * returned navigable set supports all optional Set operations.

- * - * The navigable set returned by this method will throw an - * IllegalArgumentException if the user attempts to insert an - * 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 of a specified value, merely request the subrange - * from lowEndpoint to successor(highEndpoint). - * For example, suppose that s is a navigable set of - * strings. The following idiom obtains a view containing all of - * the strings in s from low to high, - * inclusive: - *

 NavigableSet sub = s.navigableSubSet(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:
-     *     NavigableSet sub = s.navigableSubSet(low+"\0", high);
-     * 
- * - * @param fromElement low endpoint (inclusive) of the range. - * @param toElement high endpoint (exclusive) of the range. - * @return a view of the portion of this set whose elements range from - * fromElement, inclusive, to toElement, - * exclusive. - * @throws ClassCastException if fromElement and - * toElement cannot be compared to one another using - * this set's comparator (or, if the set has no comparator, - * using natural ordering). - * @throws IllegalArgumentException if fromElement is greater than - * toElement. + * @throws ClassCastException {@inheritDoc} * @throws NullPointerException if fromElement or - * toElement is null and this set uses natural - * order, or its comparator does not tolerate null - * elements. + * toElement is null and this set uses natural ordering, + * or its comparator does not permit null elements + * @throws IllegalArgumentException {@inheritDoc} */ public NavigableSet navigableSubSet(E fromElement, E toElement) { return new TreeSet(m.navigableSubMap(fromElement, toElement)); } /** - * Returns a view of the portion of this set whose elements are - * strictly less than toElement. The returned navigable - * set is backed by this set, so changes in the returned navigable - * set are reflected in this set, and vice-versa. The returned - * navigable set supports all optional set operations.

- * - * The navigable set returned by this method will throw an - * IllegalArgumentException if the user attempts to - * insert an element greater than or equal to - * toElement.

- * - * 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 of a specified value, merely request a headSet - * bounded by successor(highEndpoint). For example, - * suppose that s is a navigable set of strings. The - * following idiom obtains a view containing all of the strings in - * s that are less than or equal to high: - *

 NavigableSet head = s.navigableHeadSet(high+"\0");
- * - * @param toElement high endpoint (exclusive) of the headSet. - * @return a view of the portion of this set whose elements are strictly - * less than toElement. - * @throws ClassCastException if toElement is not compatible - * with this set's comparator (or, if the set has no comparator, - * if toElement does not implement Comparable). - * @throws IllegalArgumentException if this set is itself a subset, - * and toElement is not within the - * specified range of the subset. - * @throws NullPointerException if toElement is null and - * this set uses natural ordering, or its comparator does - * not tolerate null elements. + * @throws ClassCastException {@inheritDoc} + * @throws NullPointerException if toElement is null and + * this set uses natural ordering, or its comparator does + * not permit null elements + * @throws IllegalArgumentException {@inheritDoc} */ public NavigableSet navigableHeadSet(E toElement) { return new TreeSet(m.navigableHeadMap(toElement)); } /** - * Returns a view of the portion of this set whose elements are - * greater than or equal to fromElement. The returned - * navigable set is backed by this set, so changes in the returned - * navigable set are reflected in this set, and vice-versa. The - * returned navigable set supports all optional set operations.

- * - * The navigable set returned by this method will throw an - * IllegalArgumentException if the user attempts to insert an - * element less than fromElement. - * - * 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 of a specified value, merely request a tailSet - * bounded by successor(lowEndpoint). For example, - * suppose that s is a navigable set of strings. The - * following idiom obtains a view containing all of the strings in - * s that are strictly greater than low: - *

  NavigableSet tail = s.navigableTailSet(low+"\0");
-     * 
- * - * @param fromElement low endpoint (inclusive) of the tailSet. - * @return a view of the portion of this set whose elements are - * greater than or equal to fromElement. - * @throws ClassCastException if fromElement is not compatible - * with this set's comparator (or, if the set has no comparator, - * if fromElement does not implement Comparable). - * @throws IllegalArgumentException if this set is itself a subset, - * and fromElement is not within the - * specified range of the subset. - * @throws NullPointerException if fromElement is null - * and this set uses natural ordering, or its comparator does - * not tolerate null elements. + * @throws ClassCastException {@inheritDoc} + * @throws NullPointerException if fromElement is null and + * this set uses natural ordering, or its comparator does + * not permit null elements + * @throws IllegalArgumentException {@inheritDoc} */ public NavigableSet navigableTailSet(E fromElement) { return new TreeSet(m.navigableTailMap(fromElement)); } - /** - * Equivalent to navigableSubSet but with a return - * type conforming to the SortedSet interface. - * @param fromElement low endpoint (inclusive) of the range. - * @param toElement high endpoint (exclusive) of the range. - * @return a view of the portion of this set whose elements range from - * fromElement, inclusive, to toElement, - * exclusive. - * @throws ClassCastException if fromElement and - * toElement cannot be compared to one another using - * this set's comparator (or, if the set has no comparator, - * using natural ordering). - * @throws IllegalArgumentException if fromElement is greater than - * toElement. + * Equivalent to {@link #navigableSubSet} but with a return type + * conforming to the SortedSet interface. + * + *

{@inheritDoc} + * + * @throws ClassCastException {@inheritDoc} * @throws NullPointerException if fromElement or - * toElement is null and this set uses natural - * order, or its comparator does not tolerate null - * elements. + * toElement is null and this set uses natural ordering, + * or its comparator does not permit null elements + * @throws IllegalArgumentException {@inheritDoc} */ public SortedSet subSet(E fromElement, E toElement) { return new TreeSet(m.navigableSubMap(fromElement, toElement)); } /** - * Equivalent to navigableHeadSet but with a return - * type conforming to the SortedSet interface. + * Equivalent to {@link #navigableHeadSet} but with a return type + * conforming to the SortedSet interface. + * + *

{@inheritDoc} * - * @param toElement high endpoint (exclusive) of the headSet. - * @return a view of the portion of this set whose elements are strictly - * less than toElement. - * @throws ClassCastException if toElement is not compatible - * with this set's comparator (or, if the set has no comparator, - * if toElement does not implement Comparable). - * @throws IllegalArgumentException if this set is itself a subset, - * and toElement is not within the - * specified range of the subset. - * @throws NullPointerException if toElement is null and - * this set uses natural ordering, or its comparator does - * not tolerate null elements. + * @throws ClassCastException {@inheritDoc} + * @throws NullPointerException if toElement is null + * and this set uses natural ordering, or its comparator does + * not permit null elements + * @throws IllegalArgumentException {@inheritDoc} */ public SortedSet headSet(E toElement) { return new TreeSet(m.navigableHeadMap(toElement)); } /** - * Equivalent to navigableTailSet but with a return - * type conforming to the SortedSet interface. - * @param fromElement low endpoint (inclusive) of the tailSet. - * @return a view of the portion of this set whose elements are - * greater than or equal to fromElement. - * @throws ClassCastException if fromElement is not compatible - * with this set's comparator (or, if the set has no comparator, - * if fromElement does not implement Comparable). - * @throws IllegalArgumentException if this set is itself a subset, - * and fromElement is not within the - * specified range of the subset. - * @throws NullPointerException if fromElement is null - * and this set uses natural ordering, or its comparator does - * not tolerate null elements. + * Equivalent to {@link #navigableTailSet} but with a return type + * conforming to the SortedSet interface. + * + *

{@inheritDoc} + * + * @throws ClassCastException {@inheritDoc} + * @throws NullPointerException if fromElement is null + * and this set uses natural ordering, or its comparator does + * not permit null elements + * @throws IllegalArgumentException {@inheritDoc} */ public SortedSet tailSet(E fromElement) { return new TreeSet(m.navigableTailMap(fromElement)); } - /** - * Returns the comparator used to order this sorted set, or null - * if this tree set uses its elements natural ordering. - * - * @return the comparator used to order this sorted set, or null - * if this tree set uses its elements natural ordering. - */ public Comparator comparator() { return m.comparator(); } /** - * Returns the first (lowest) element currently in this sorted set. - * - * @return the first (lowest) element currently in this sorted set. - * @throws NoSuchElementException sorted set is empty. + * @throws NoSuchElementException {@inheritDoc} */ public E first() { return m.firstKey(); } /** - * Returns the last (highest) element currently in this sorted set. - * - * @return the last (highest) element currently in this sorted set. - * @throws NoSuchElementException sorted set is empty. + * @throws NoSuchElementException {@inheritDoc} */ public E last() { return m.lastKey(); @@ -506,90 +377,51 @@ public class TreeSet // NavigableSet API methods - /** - * Returns an element greater than or equal to the given element, or - * null if there is no such element. - * - * @param e the value to match - * @return an element greater than or equal to given element, or - * null if there is no such element. - * @throws ClassCastException if e cannot be compared with the elements - * currently in the set. - * @throws NullPointerException if e is null and this map - * uses natural ordering and is non-empty, or its comparator does - * not tolerate null keys. - */ - public E ceiling(E e) { - return m.ceilingKey(e); - } - - /** - * Returns an element strictly less than the given element, or - * null if there is no such element. - * - * @param e the value to match - * @return the greatest element less than the given element, or - * null if there is no such element. - * @throws ClassCastException if e cannot be compared with the elements - * currently in the set. - * @throws NullPointerException if e is null and this map - * uses natural ordering and is non-empty, or its comparator does - * not tolerate null keys. + * @throws ClassCastException {@inheritDoc} + * @throws NullPointerException if the specified element is null and + * this set uses natural ordering and is non-empty, + * or its comparator does not permit null elements */ public E lower(E e) { return m.lowerKey(e); } /** - * Returns an element less than or equal to the given element, or - * null if there is no such element. - * - * @param e the value to match - * @return the greatest element less than or equal to given - * element, or null if there is no such element. - * @throws ClassCastException if e cannot be compared with the elements - * currently in the set. - * @throws NullPointerException if e is null and this map - * uses natural ordering and is non-empty, or its comparator does - * not tolerate null keys. + * @throws ClassCastException {@inheritDoc} + * @throws NullPointerException if the specified element is null and + * this set uses natural ordering and is non-empty, + * or its comparator does not permit null elements */ public E floor(E e) { return m.floorKey(e); } /** - * Returns an element strictly greater than the given element, or - * null if there is no such element. - * - * @param e the value to match - * @return the least element greater than the given element, or - * null if there is no such element. - * @throws ClassCastException if e cannot be compared with the elements - * currently in the set. - * @throws NullPointerException if e is null and this map - * uses natural ordering and is non-empty, or its comparator does - * not tolerate null keys. + * @throws ClassCastException {@inheritDoc} + * @throws NullPointerException if the specified element is null and + * this set uses natural ordering and is non-empty, + * or its comparator does not permit null elements */ - public E higher(E e) { - return m.higherKey(e); + public E ceiling(E e) { + return m.ceilingKey(e); } /** - * Retrieves and removes the first (lowest) element. - * - * @return the least element, or null if empty. + * @throws ClassCastException {@inheritDoc} + * @throws NullPointerException if the specified element is null and + * this set uses natural ordering and is non-empty, + * or its comparator does not permit null elements */ + public E higher(E e) { + return m.higherKey(e); + } + public E pollFirst() { Map.Entry e = m.pollFirstEntry(); return (e == null)? null : e.getKey(); } - /** - * Retrieves and removes the last (highest) element. - * - * @return the last element, or null if empty. - */ public E pollLast() { Map.Entry e = m.pollLastEntry(); return (e == null)? null : e.getKey(); @@ -599,7 +431,7 @@ public class TreeSet * Returns a shallow copy of this TreeSet instance. (The elements * themselves are not cloned.) * - * @return a shallow copy of this set. + * @return a shallow copy of this set */ public Object clone() { TreeSet clone = null; @@ -619,11 +451,11 @@ public class TreeSet * serialize it). * * @serialData Emits the comparator used to order this set, or - * null if it obeys its elements' natural ordering - * (Object), followed by the size of the set (the number of - * elements it contains) (int), followed by all of its - * elements (each an Object) in order (as determined by the - * set's Comparator, or by the elements' natural ordering if + * null if it obeys its elements' natural ordering + * (Object), followed by the size of the set (the number of + * elements it contains) (int), followed by all of its + * elements (each an Object) in order (as determined by the + * set's Comparator, or by the elements' natural ordering if * the set has no Comparator). */ private void writeObject(java.io.ObjectOutputStream s)