Add EnumSet.stream(Class)

Author: garydgregory

src/changes/changes.xml

@@ -137,6 +137,7 @@ The <action> type attribute can be add,update,fix,remove.
     <action                   type="add" dev="ggregory" due-to="Gary Gregory">Add org.apache.commons.lang3.concurrent.locks.LockingVisitors.create(Object, ReentrantLock).</action>
     <action                   type="add" dev="ggregory" due-to="Gary Gregory">Add org.apache.commons.lang3.concurrent.locks.LockingVisitors.ReentrantLockVisitor.</action>
     <action                   type="add" dev="ggregory" due-to="Gary Gregory">Add builders for LockingVisitors implementations.</action>
+    <action                   type="add" dev="ggregory" due-to="Gary Gregory">Add EnumSet.stream(Class).</action>
     <!-- UPDATE -->
     <action                   type="update" dev="ggregory" due-to="Gary Gregory, Dependabot">Bump org.apache.commons:commons-parent from 73 to 85 #1267, #1277, #1283, #1288, #1302, #1377.</action>
     <action                   type="update" dev="ggregory" due-to="Gary Gregory, Dependabot">[site] Bump org.codehaus.mojo:taglist-maven-plugin from 3.1.0 to 3.2.1 #1300.</action>

src/main/java/org/apache/commons/lang3/EnumUtils.java

@@ -28,6 +28,8 @@
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
+import org.apache.commons.lang3.stream.Streams;
+
 /**
  * Utility library to provide helper methods for Java enums.
  *
@@ -68,8 +70,8 @@ private static <E extends Enum<E>> Class<E> asEnum(final Class<E> enumClass) {
      */
     private static <E extends Enum<E>> Class<E> checkBitVectorable(final Class<E> enumClass) {
         final E[] constants = asEnum(enumClass).getEnumConstants();
-        Validate.isTrue(constants.length <= Long.SIZE, CANNOT_STORE_S_S_VALUES_IN_S_BITS,
-            Integer.valueOf(constants.length), enumClass.getSimpleName(), Integer.valueOf(Long.SIZE));
+        Validate.isTrue(constants.length <= Long.SIZE, CANNOT_STORE_S_S_VALUES_IN_S_BITS, Integer.valueOf(constants.length), enumClass.getSimpleName(),
+                Integer.valueOf(Long.SIZE));
         return enumClass;
     }
 
@@ -298,7 +300,7 @@ public static <E extends Enum<E>> Map<String, E> getEnumMap(final Class<E> enumC
      * @since 3.13.0
      */
     public static <E extends Enum<E>, K> Map<K, E> getEnumMap(final Class<E> enumClass, final Function<E, K> keyFunction) {
-        return Stream.of(enumClass.getEnumConstants()).collect(Collectors.toMap(keyFunction::apply, Function.identity()));
+        return stream(enumClass).collect(Collectors.toMap(keyFunction::apply, Function.identity()));
     }
 
     /**
@@ -341,7 +343,7 @@ public static <E extends Enum<E>> E getFirstEnum(final Class<E> enumClass, final
         if (isEnum(enumClass)) {
             return defaultEnum;
         }
-        return Stream.of(enumClass.getEnumConstants()).filter(e -> value == toIntFunction.applyAsInt(e)).findFirst().orElse(defaultEnum);
+        return stream(enumClass).filter(e -> value == toIntFunction.applyAsInt(e)).findFirst().orElse(defaultEnum);
     }
 
     /**
@@ -363,7 +365,7 @@ public static <E extends Enum<E>> E getFirstEnumIgnoreCase(final Class<E> enumCl
             if (enumName == null || !enumClass.isEnum()) {
                 return defaultEnum;
             }
-            return Stream.of(enumClass.getEnumConstants()).filter(e -> enumName.equalsIgnoreCase(stringFunction.apply(e))).findFirst().orElse(defaultEnum);
+            return stream(enumClass).filter(e -> enumName.equalsIgnoreCase(stringFunction.apply(e))).findFirst().orElse(defaultEnum);
         }
 
     private static <E extends Enum<E>> boolean isEnum(final Class<E> enumClass) {
@@ -416,8 +418,7 @@ public static <E extends Enum<E>> boolean isValidEnumIgnoreCase(final Class<E> e
      * @since 3.0.1
      */
     public static <E extends Enum<E>> EnumSet<E> processBitVector(final Class<E> enumClass, final long value) {
-        checkBitVectorable(enumClass).getEnumConstants();
-        return processBitVectors(enumClass, value);
+        return processBitVectors(checkBitVectorable(enumClass), value);
     }
 
     /**
@@ -437,15 +438,28 @@ public static <E extends Enum<E>> EnumSet<E> processBitVectors(final Class<E> en
         final EnumSet<E> results = EnumSet.noneOf(asEnum(enumClass));
         final long[] lvalues = ArrayUtils.clone(Objects.requireNonNull(values, "values"));
         ArrayUtils.reverse(lvalues);
-        for (final E constant : enumClass.getEnumConstants()) {
+        stream(enumClass).forEach(constant -> {
             final int block = constant.ordinal() / Long.SIZE;
             if (block < lvalues.length && (lvalues[block] & 1L << constant.ordinal() % Long.SIZE) != 0) {
                 results.add(constant);
             }
-        }
+        });
         return results;
     }
 
+    /**
+     * Returns a sequential ordered stream whose elements are the given class' enum values.
+     *
+     * @param <T>   the type of stream elements.
+     * @param clazz the class containing the enum values.
+     * @return the new stream.
+     * @since 3.18.0
+     * @see Class#getEnumConstants()
+     */
+    public static <T> Stream<T> stream(final Class<T> clazz) {
+        return Streams.of(clazz.getEnumConstants());
+    }
+
     /**
      * This constructor is public to permit tools that require a JavaBean
      * instance to operate.

src/test/java/org/apache/commons/lang3/EnumUtilsTest.java

@@ -31,6 +31,7 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.TimeUnit;
 import java.util.function.Function;
 import java.util.function.ToIntFunction;
 
@@ -606,6 +607,13 @@ void testProcessBitVectors_nullClass() {
         assertNullPointerException(() -> EnumUtils.processBitVectors(empty, 0L));
     }
 
+    @Test
+    void testStream() {
+        assertEquals(7, EnumUtils.stream(TimeUnit.class).count());
+        Assertions.assertArrayEquals(TimeUnit.values(), EnumUtils.stream(TimeUnit.class).toArray(TimeUnit[]::new));
+        assertEquals(0, EnumUtils.stream(Object.class).count());
+    }
+
 }
 
 enum Month {