--- jsr166/src/jsr166x/ConcurrentSkipListSet.java 2004/09/06 17:01:54 1.2
+++ jsr166/src/jsr166x/ConcurrentSkipListSet.java 2004/10/16 14:49:45 1.4
@@ -28,15 +28,20 @@ import java.util.concurrent.*;
* other operations.
*
* Beware that, unlike in most collections, the size
- * method is NOT a constant-time operation. Because of the
+ * method is not a constant-time operation. Because of the
* asynchronous nature of these sets, determining the current number
- * of elements requires a traversal of the elements.
+ * of elements requires a traversal of the elements. Additionally, the
+ * bulk operations addAll, removeAll,
+ * <retainAll, and tt>containsAll are not
+ * guaranteed to be performed atomically. For example, an iterator
+ * operating concurrently with an addAll operation might view
+ * only some of the added elements.
*
*
This class and its iterators implement all of the
* optional methods of the {@link Set} and {@link Iterator}
* interfaces. Like most other concurrent collection implementations,
* this class does not permit the use of null elements.
- * because null arguments and return values cannot be reliably
+ * because null arguments and return values cannot be reliably
* distinguished from the absence of elements.
*
* @author Doug Lea
@@ -85,7 +90,8 @@ public class ConcurrentSkipListSet
*
* @throws ClassCastException if the elements in the specified
* collection are not comparable, or are not mutually comparable.
- * @throws NullPointerException if the specified collection is null.
+ * @throws NullPointerException if the specified collection is
+ * null.
*/
public ConcurrentSkipListSet(Collection c) {
m = new ConcurrentSkipListMap();
@@ -97,7 +103,8 @@ public class ConcurrentSkipListSet
* sorted set, sorted according to the same ordering.
*
* @param s sorted set whose elements will comprise the new set.
- * @throws NullPointerException if the specified sorted set is null.
+ * @throws NullPointerException if the specified sorted set is
+ * null.
*/
public ConcurrentSkipListSet(SortedSet s) {
m = new ConcurrentSkipListMap(s.comparator());
@@ -212,16 +219,70 @@ public class ConcurrentSkipListSet
public Iterator iterator() {
return m.keyIterator();
}
+
+ /* ---------------- AbstractSet Overrides -------------- */
+
+ /**
+ * 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.
+ *
+ * @param o Object to be compared for equality with this set.
+ * @return true if the specified Object is equal to this set.
+ */
+ public boolean equals(Object o) {
+ // Override AbstractSet version to avoid calling size()
+ if (o == this)
+ return true;
+ if (!(o instanceof Set))
+ return false;
+ Collection c = (Collection) o;
+ try {
+ return containsAll(c) && c.containsAll(this);
+ } catch(ClassCastException unused) {
+ return false;
+ } catch(NullPointerException unused) {
+ return false;
+ }
+ }
+
+ /**
+ * Removes from this set all of its elements that are 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 asymmetric set difference of the two sets.
+ *
+ * @param c collection that defines which elements will be removed from
+ * this set.
+ * @return true if this set changed as a result of the call.
+ *
+ * @throws ClassCastException if the types of one or more elements in this
+ * set are incompatible with the specified collection
+ * @throws NullPointerException if the specified collection, or any
+ * of its elements are null.
+ */
+ public boolean removeAll(Collection c) {
+ // Override AbstractSet version to avoid unnecessary call to size()
+ boolean modified = false;
+ for (Iterator i = c.iterator(); i.hasNext(); )
+ if (remove(i.next()))
+ modified = true;
+ return modified;
+ }
/* ---------------- Relational operations -------------- */
/**
* Returns an element greater than or equal to the given element, or
- * null if there is no such element.
+ * null if there is no such element.
*
* @param o the value to match
- * @return an element greater than or equal to given element, or null
- * if there is no such element.
+ * @return an element greater than or equal to given element, or
+ * null if there is no such element.
* @throws ClassCastException if o cannot be compared with the elements
* currently in the set.
* @throws NullPointerException if o is null
@@ -231,12 +292,12 @@ public class ConcurrentSkipListSet
}
/**
- * Returns an element strictly less than the given element, or null if
- * there is no such element.
+ * Returns an element strictly less than the given element, or
+ * null if there is no such element.
*
* @param o the value to match
* @return the greatest element less than the given element, or
- * null if there is no such element.
+ * null if there is no such element.
* @throws ClassCastException if o cannot be compared with the elements
* currently in the set.
* @throws NullPointerException if o is null.
@@ -246,12 +307,12 @@ public class ConcurrentSkipListSet
}
/**
- * Returns an element less than or equal to the given element, or null
- * if there is no such element.
+ * Returns an element less than or equal to the given element, or
+ * null if there is no such element.
*
* @param o the value to match
* @return the greatest element less than or equal to given
- * element, or null if there is no such element.
+ * element, or null if there is no such element.
* @throws ClassCastException if o cannot be compared with the elements
* currently in the set.
* @throws NullPointerException if o is null.
@@ -261,12 +322,12 @@ public class ConcurrentSkipListSet
}
/**
- * Returns an element strictly greater than the given element, or null
- * if there is no such element.
+ * Returns an element strictly greater than the given element, or
+ * null if there is no such element.
*
* @param o the value to match
* @return the least element greater than the given element, or
- * null if there is no such element.
+ * null if there is no such element.
* @throws ClassCastException if o cannot be compared with the elements
* currently in the set.
* @throws NullPointerException if o is null.
@@ -328,6 +389,8 @@ public class ConcurrentSkipListSet
return m.lastKey();
}
+
+
/**
* Returns a view of the portion of this set whose elements range from
* fromElement, inclusive, to toElement, exclusive. (If
@@ -411,8 +474,8 @@ public class ConcurrentSkipListSet
/**
* Creates a new submap.
- * @param fromElement inclusive least value, or null if from start
- * @param toElement exclusive upper bound or null if to end
+ * @param fromElement inclusive least value, or null if from start
+ * @param toElement exclusive upper bound or null if to end
* @throws IllegalArgumentException if fromElement and toElement
* nonnull and fromElement greater than toElement
*/
@@ -520,10 +583,10 @@ public class ConcurrentSkipListSet
/**
* Returns an element greater than or equal to the given
- * element, or null if there is no such element.
+ * element, or null if there is no such element.
*
* @param o the value to match
- * @return an element greater than or equal to given element, or null
+ * @return an element greater than or equal to given element, or null
* if there is no such element.
* @throws ClassCastException if o cannot be compared with the
* elements currently in the set.
@@ -539,12 +602,12 @@ public class ConcurrentSkipListSet
}
/**
- * Returns an element strictly less than the given element, or null if
+ * Returns an element strictly less than the given element, or null if
* there is no such element.
*
* @param o the value to match
* @return the greatest element less than the given element, or
- * null if there is no such element.
+ * null if there is no such element.
* @throws ClassCastException if o cannot be compared with the
* elements currently in the set.
* @throws NullPointerException if o is null.
@@ -555,12 +618,12 @@ public class ConcurrentSkipListSet
}
/**
- * Returns an element less than or equal to the given element, or null
+ * Returns an element less than or equal to the given element, or null
* if there is no such element.
*
* @param o the value to match
* @return the greatest element less than or equal to given
- * element, or null if there is no such element.
+ * element, or null if there is no such element.
* @throws ClassCastException if o cannot be compared with the
* elements currently in the set.
* @throws NullPointerException if o is null.
@@ -571,12 +634,12 @@ public class ConcurrentSkipListSet
}
/**
- * Returns an element strictly greater than the given element, or null
+ * Returns an element strictly greater than the given element, or null
* if there is no such element.
*
* @param o the value to match
* @return the least element greater than the given element, or
- * null if there is no such element.
+ * null if there is no such element.
* @throws ClassCastException if o cannot be compared with the
* elements currently in the set.
* @throws NullPointerException if o is null.
@@ -734,6 +797,4 @@ public class ConcurrentSkipListSet
fromElement, fence);
}
}
-
-
}