[COLLECTIONS-451] Hide constructors for *Utils classes.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/collections/trunk@1457508 13f79535-47bb-0310-9956-ffa450edef68

src/main/java/org/apache/commons/collections/BagUtils.java

@@ -47,11 +47,9 @@ public class BagUtils {
             UnmodifiableSortedBag.unmodifiableSortedBag(new TreeBag<Object>());
 
     /**
-     * Instantiation of BagUtils is not intended or required. However, some
-     * tools require an instance to operate.
+     * Instantiation of BagUtils is not intended or required.
      */
-    public BagUtils() {
-    }
+    private BagUtils() {}
 
     //-----------------------------------------------------------------------
     /**

src/main/java/org/apache/commons/collections/ClosureUtils.java

@@ -55,9 +55,7 @@ public class ClosureUtils {
     /**
      * This class is not normally instantiated.
      */
-    public ClosureUtils() {
-        super();
-    }
+    private ClosureUtils() {}
 
     /**
      * Gets a Closure that always throws an exception.

src/main/java/org/apache/commons/collections/CollectionUtils.java

@@ -195,8 +195,7 @@ public class CollectionUtils {
     /**
      * <code>CollectionUtils</code> should not normally be instantiated.
      */
-    public CollectionUtils() {
-    }
+    private CollectionUtils() {}
 
     /**
      * Returns the immutable EMPTY_COLLECTION with generic type safety.

src/main/java/org/apache/commons/collections/ComparatorUtils.java

@@ -43,8 +43,7 @@ public class ComparatorUtils {
     /**
      * ComparatorUtils should not normally be instantiated.
      */
-    public ComparatorUtils() {
-    }
+    private ComparatorUtils() {}
 
     /**
      * Comparator for natural sort order.

src/main/java/org/apache/commons/collections/EnumerationUtils.java

@@ -34,9 +34,7 @@ public class EnumerationUtils {
     /**
      * EnumerationUtils is not normally instantiated.
      */
-    public EnumerationUtils() {
-        // no init.
-    }
+    private EnumerationUtils() {}
     
     /**
      * Creates a list based on an enumeration.

src/main/java/org/apache/commons/collections/FactoryUtils.java

@@ -41,9 +41,7 @@ public class FactoryUtils {
     /**
      * This class is not normally instantiated.
      */
-    public FactoryUtils() {
-        super();
-    }
+    private FactoryUtils() {}
 
     /**
      * Gets a Factory that always throws an exception.

src/main/java/org/apache/commons/collections/IteratorUtils.java

@@ -112,8 +112,7 @@ public class IteratorUtils {
     /**
      * IteratorUtils is not normally instantiated.
      */
-    public IteratorUtils() {
-    }
+    private IteratorUtils() {}
 
     // Empty
     //-----------------------------------------------------------------------

src/main/java/org/apache/commons/collections/ListUtils.java

@@ -50,8 +50,7 @@ public class ListUtils {
     /**
      * <code>ListUtils</code> should not normally be instantiated.
      */
-    public ListUtils() {
-    }
+    private ListUtils() {}
 
     //-----------------------------------------------------------------------
     

src/main/java/org/apache/commons/collections/MapUtils.java

@@ -97,8 +97,7 @@ public class MapUtils {
     /**
      * <code>MapUtils</code> should not normally be instantiated.
      */
-    public MapUtils() {
-    }
+    private MapUtils() {}
 
     // Type safe getters
     //-------------------------------------------------------------------------

src/main/java/org/apache/commons/collections/PredicateUtils.java

@@ -74,9 +74,7 @@ public class PredicateUtils {
     /**
      * This class is not normally instantiated.
      */
-    public PredicateUtils() {
-        super();
-    }
+    private PredicateUtils() {}
 
     // Simple predicates
     //-----------------------------------------------------------------------------

src/main/java/org/apache/commons/collections/SetUtils.java

@@ -77,8 +77,7 @@ public class SetUtils {
     /**
      * <code>SetUtils</code> should not normally be instantiated.
      */
-    public SetUtils() {
-    }
+    private SetUtils() {}
 
     //-----------------------------------------------------------------------
     

src/main/java/org/apache/commons/collections/SplitMapUtils.java

@@ -41,8 +41,9 @@ public class SplitMapUtils {
     /**
      * <code>SplitMapUtils</code> should not normally be instantiated.
      */
-    public SplitMapUtils() {
-    }
+    private SplitMapUtils() {}
+
+    //-----------------------------------------------------------------------
 
     private static class WrappedGet<K, V> implements IterableMap<K, V>, Unmodifiable {
         private final Get<K, V> get;
@@ -193,6 +194,8 @@ public class SplitMapUtils {
         }
     }
 
+    //-----------------------------------------------------------------------
+
     /**
      * Get the specified {@link Get} as an instance of {@link IterableMap}.
      * If <code>get</code> implements {@link IterableMap} directly, no conversion will take place.

src/main/java/org/apache/commons/collections/TransformerUtils.java

@@ -64,9 +64,7 @@ public class TransformerUtils {
     /**
      * This class is not normally instantiated.
      */
-    public TransformerUtils() {
-        super();
-    }
+    private TransformerUtils() {}
 
     /**
      * Gets a transformer that always throws an exception.

src/test/java/org/apache/commons/collections/CollectionUtilsTest.java

@@ -1523,15 +1523,6 @@ public class CollectionUtilsTest extends MockTestCase {
                 (Object)map, 0));
     }
 
-    /**
-     * TODO: Should {@link CollectionUtils} be able to be extended? If it is extended, subclasses must 'override' the static methods with
-     * call-throughs anyhow, otherwise java compiler warnings will result
-     */
-    @Test
-    public void ensureCollectionUtilsCanBeExtended() {
-        new CollectionUtils() {};
-    }
-
     @Test
     public void reverse() {
         CollectionUtils.reverseArray(new Object[] {});