MATH-259 - check for Comparable when adding values

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@765996 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/commons/math/stat/Frequency.java

@@ -101,9 +101,26 @@ public class Frequency implements Serializable {
      * </p>
      * 
      * @param v the value to add.
-     * @throws IllegalArgumentException if <code>v</code> is not comparable.
+     * @throws IllegalArgumentException if <code>v</code> is not comparable with previous entries
+     * @throws ClassCastException if <code>v</code> is not Comparable
+     * @deprecated use {@link #addValue(Comparable)} instead
      */
+    @Deprecated
     public void addValue(Object v) {
+        addValue((Comparable<?>) v);
+    }
+    
+    /**
+     * Adds 1 to the frequency count for v.
+     * <p>
+     * If other objects have already been added to this Frequency, v must
+     * be comparable to those that have already been added.
+     * </p>
+     * 
+     * @param v the value to add.
+     * @throws IllegalArgumentException if <code>v</code> is not comparable with previous entries
+     */
+    public void addValue(Comparable<?>v){
         Object obj = v;
         if (v instanceof Integer) {
            obj = Long.valueOf(((Integer) v).longValue());

src/test/org/apache/commons/math/stat/FrequencyTest.java

@@ -189,6 +189,22 @@ public final class FrequencyTest extends TestCase {
         }
     }
     
+    // Check what happens when non-Comparable objects are added
+    public void testAddNonComparable(){
+        try {
+            f.addValue(new Object()); // This was OK
+            fail("Expected ClassCastException");
+        } catch (ClassCastException expected) {
+        }
+        f.clear();
+        f.addValue(1);
+        try {
+            f.addValue(new Object());
+            fail("Expected ClassCastException"); // Previously would have been IllegalArgument
+        } catch (ClassCastException expected) {
+        }
+    }
+
     /** test empty table */
     public void testEmptyTable() {
         assertEquals("freq sum, empty table", 0, f.getSumFreq());