Made DSet (sort of) type safe. To be really really typesafe DSet.Entry would

have to be parameterized on the type of the Comparable that is returned by
getKey(), but that turns out to be a twisty maze of generics that is not
obvious to me how to express using Java's generics syntax and it opens up
various cans of worms that I don't have time to solve right now. So we'll
settle for the DSet itself being parameterized on the Entry class and the Entry
class being non-type safe.


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@4051 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/presents/dobj/DSet.java

@@ -54,7 +54,7 @@ import com.threerings.presents.Log;
  * bandwidth. Lastly, the object returned by {@link Entry#getKey} must be
  * a {@link Streamable} type.
  */
-public class DSet
+public class DSet<E extends DSet.Entry>
     implements Streamable, Cloneable
 {
     /**
@@ -81,10 +81,10 @@ public class DSet
      * @param source an iterator from which we will initially populate the
      * set.
      */
-    public DSet (Iterator source)
+    public DSet (Iterator<E> source)
     {
         while (source.hasNext()) {
-            add((Entry)source.next());
+            add(source.next());
         }
     }
 
@@ -99,7 +99,7 @@ public class DSet
      * @param source an array from which we will initially populate the
      * set.
      */
-    public DSet (Entry[] source)
+    public DSet (E[] source)
     {
         for (int ii = 0; ii < source.length; ii++) {
             if (source[ii] != null) {
@@ -129,7 +129,7 @@ public class DSet
      * <code>equals()</code> the key returned by <code>getKey()</code> of
      * the supplied entry. Returns false otherwise.
      */
-    public boolean contains (Entry elem)
+    public boolean contains (E elem)
     {
         return containsKey(elem.getKey());
     }
@@ -148,13 +148,12 @@ public class DSet
      * the specified key or null if no entry could be found that matches
      * the key.
      */
-    public Entry get (Comparable key)
+    public E get (Comparable key)
     {
         // determine where we'll be adding the new element
         int eidx = ArrayUtil.binarySearch(
             _entries, 0, _size, key, ENTRY_COMP);
-
+        return (eidx < 0) ? null : (E)_entries[eidx];
-        return (eidx < 0) ? null : _entries[eidx];
     }
 
     /**
@@ -165,7 +164,7 @@ public class DSet
      *
      * @deprecated
      */
-    public Iterator entries ()
+    public Iterator<E> entries ()
     {
         return iterator();
     }
@@ -176,7 +175,7 @@ public class DSet
      * made to the set). It should not be kept around as it can quickly
      * become out of date.
      */
-    public Iterator iterator ()
+    public Iterator<E> iterator ()
     {
         // the crazy sanity checks
         if (_size < 0 ||_size > _entries.length ||
@@ -186,14 +185,14 @@ public class DSet
             Thread.dumpStack();
         }
 
-        return new Iterator() {
+        return new Iterator<E>() {
             public boolean hasNext () {
                 checkComodification();
                 return (_index < _size);
             }
-            public Object next () {
+            public E next () {
                 checkComodification();
-                return _entries[_index++];
+                return (E)_entries[_index++];
             }
             public void remove () {
                 throw new UnsupportedOperationException();
@@ -224,10 +223,10 @@ public class DSet
      * size to contain all of the elements of this set will be created and
      * returned.
      */
-    public Object[] toArray (Object[] array)
+    public E[] toArray (E[] array)
     {
         if (array == null) {
-            array = new Object[size()];
+            array = (E[])new Object[size()];
         }
         System.arraycopy(_entries, 0, array, 0, array.length);
         return array;
@@ -242,7 +241,7 @@ public class DSet
      * @return true if the entry was added, false if it was already in
      * the set.
      */
-    protected boolean add (Entry elem)
+    protected boolean add (E elem)
     {
         // determine where we'll be adding the new element
         int eidx = ArrayUtil.binarySearch(
@@ -297,7 +296,7 @@ public class DSet
      * @return true if the entry was removed, false if it was not in the
      * set.
      */
-    protected boolean remove (Entry elem)
+    protected boolean remove (E elem)
     {
         return (null != removeKey(elem.getKey()));
     }
@@ -311,7 +310,7 @@ public class DSet
      * @return the old matching entry if found and removed, null if not
      * found.
      */
-    protected Entry removeKey (Object key)
+    protected E removeKey (Comparable key)
     {
         // look up this entry's position in our set
         int eidx = ArrayUtil.binarySearch(
@@ -320,7 +319,7 @@ public class DSet
         // if we found it, remove it
         if (eidx >= 0) {
             // extract the old entry
-            Entry oldEntry = _entries[eidx];
+            E oldEntry = (E)_entries[eidx];
             _size--;
             if ((_entries.length > INITIAL_CAPACITY) &&
                     (_size < _entries.length/8)) {
@@ -353,7 +352,7 @@ public class DSet
      * @return the old entry that was replaced, or null if it was not
      * found (in which case nothing is updated).
      */
-    protected Entry update (Entry elem)
+    protected E update (E elem)
     {
         // look up this entry's position in our set
         int eidx = ArrayUtil.binarySearch(
@@ -361,7 +360,7 @@ public class DSet
 
         // if we found it, update it
         if (eidx >= 0) {
-            Entry oldEntry = _entries[eidx];
+            E oldEntry = (E)_entries[eidx];
             _entries[eidx] = elem;
             _modCount++;
             return oldEntry;
@@ -427,7 +426,7 @@ public class DSet
         }
         _entries = new Entry[capacity];
         for (int ii = 0; ii < _size; ii++) {
-            _entries[ii] = (Entry) in.readObject();
+            _entries[ii] = (E)in.readObject();
         }
     }