Add EnumUtils.getFirstEnum(Class<E>, int, ToIntFunction<E>, E)

apache · Feb 22, 2025 · b2e66fe · b2e66fe
1 parent 03e181b
commit b2e66fe
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Showing 3 changed files with 64 additions and 14 deletions.
diff --git a/src/changes/changes.xml b/src/changes/changes.xml
@@ -101,6 +101,7 @@ The <action> type attribute can be add,update,fix,remove.
     <action                   type="add" dev="ggregory" due-to="Gary Gregory">Add IterableStringTokenizer.</action>
     <action                   type="add" dev="ggregory" due-to="Gary Gregory">Add FailableIntToFloatFunction.</action>
     <action                   type="add" dev="ggregory" due-to="Gary Gregory">Add Validate.isTrue(boolean, Supplier&lt;String&gt;).</action>
+    <action                   type="add" dev="ggregory" due-to="Gary Gregory">Add EnumUtils.getFirstEnum(Class&lt;E&gt;, int, ToIntFunction&lt;E&gt;, E).</action>
     <!-- UPDATE -->
     <action                   type="update" dev="ggregory" due-to="Gary Gregory, Dependabot">Bump org.apache.commons:commons-parent from 73 to 81 #1267, #1277, #1283, #1288, #1302.</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>

diff --git a/src/main/java/org/apache/commons/lang3/EnumUtils.java b/src/main/java/org/apache/commons/lang3/EnumUtils.java
@@ -24,6 +24,7 @@
 import java.util.Map;
 import java.util.Objects;
 import java.util.function.Function;
+import java.util.function.ToIntFunction;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
@@ -69,7 +70,6 @@ private static <E extends Enum<E>> Class<E> checkBitVectorable(final Class<E> en
         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));
-
         return enumClass;
     }
 
@@ -321,6 +321,29 @@ public static <E extends Enum<E>> E getEnumSystemProperty(final Class<E> enumCla
             : getEnum(enumClass, System.getProperty(propName), defaultEnum);
     }
 
+    /**
+     * Gets the enum for the class and value, returning {@code defaultEnum} if not found.
+     *
+     * <p>
+     * This method differs from {@link Enum#valueOf} in that it does not throw an exception for an invalid enum name and performs case insensitive matching of
+     * the name.
+     * </p>
+     *
+     * @param <E>           the type of the enumeration.
+     * @param enumClass     the class of the enum to query, not null.
+     * @param value         the enum name, null returns default enum.
+     * @param toIntFunction the function that gets an int for an enum for comparison to {@code value}.
+     * @param defaultEnum   the default enum.
+     * @return an enum, default enum if not found.
+     * @since 3.18.0
+     */
+    public static <E extends Enum<E>> E getFirstEnum(final Class<E> enumClass, final int value, final ToIntFunction<E> toIntFunction, final E defaultEnum) {
+        if (isEnum(enumClass)) {
+            return defaultEnum;
+        }
+        return Stream.of(enumClass.getEnumConstants()).filter(e -> value == toIntFunction.applyAsInt(e)).findFirst().orElse(defaultEnum);
+    }
+
     /**
      * Gets the enum for the class, returning {@code defaultEnum} if not found.
      *
@@ -332,15 +355,19 @@ public static <E extends Enum<E>> E getEnumSystemProperty(final Class<E> enumCla
      * @param enumName    the enum name, null returns default enum
      * @param stringFunction the function that gets the string for an enum for comparison to {@code enumName}.
      * @param defaultEnum the default enum
-     * @return the enum, default enum if not found
+     * @return an enum, default enum if not found
      * @since 3.13.0
      */
     public static <E extends Enum<E>> E getFirstEnumIgnoreCase(final Class<E> enumClass, final String enumName, final Function<E, String> stringFunction,
-        final E defaultEnum) {
-        if (enumName == null || !enumClass.isEnum()) {
-            return defaultEnum;
+            final E defaultEnum) {
+            if (enumName == null || !enumClass.isEnum()) {
+                return defaultEnum;
+            }
+            return Stream.of(enumClass.getEnumConstants()).filter(e -> enumName.equalsIgnoreCase(stringFunction.apply(e))).findFirst().orElse(defaultEnum);
         }
-        return Stream.of(enumClass.getEnumConstants()).filter(e -> enumName.equalsIgnoreCase(stringFunction.apply(e))).findFirst().orElse(defaultEnum);
+
+    private static <E extends Enum<E>> boolean isEnum(final Class<E> enumClass) {
+        return enumClass != null && !enumClass.isEnum();
     }
 
     /**

diff --git a/src/test/java/org/apache/commons/lang3/EnumUtilsTest.java b/src/test/java/org/apache/commons/lang3/EnumUtilsTest.java
@@ -31,16 +31,11 @@
 import java.util.List;
 import java.util.Map;
 import java.util.function.Function;
+import java.util.function.ToIntFunction;
 
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
-enum Enum64 {
-    A00, A01, A02, A03, A04, A05, A06, A07, A08, A09, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22,
-    A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A40, A41, A42, A43, A44, A45,
-    A46, A47, A48, A49, A50, A51, A52, A53, A54, A55, A56, A57, A58, A59, A60, A61, A62, A63
-}
-
 /**
  */
 public class EnumUtilsTest extends AbstractLangTest {
@@ -438,6 +433,21 @@ public void testGetFirstEnumIgnoreCase_defaultEnum() {
         assertNull(EnumUtils.getFirstEnumIgnoreCase(Traffic2.class, "PURPLE", f, null));
     }
 
+    @Test
+    public void testGetFirstEnumToIntFunction() {
+        final ToIntFunction<Traffic2> f = Traffic2::getValue;
+        assertEquals(Traffic2.RED, EnumUtils.getFirstEnum(Traffic2.class, 1, f, Traffic2.AMBER));
+        assertEquals(Traffic2.AMBER, EnumUtils.getFirstEnum(Traffic2.class, 2, f, Traffic2.GREEN));
+        assertEquals(Traffic2.GREEN, EnumUtils.getFirstEnum(Traffic2.class, 3, f, Traffic2.RED));
+        assertEquals(Traffic2.AMBER, EnumUtils.getFirstEnum(Traffic2.class, 4, f, Traffic2.AMBER));
+        assertEquals(Traffic2.GREEN, EnumUtils.getFirstEnum(Traffic2.class, 5, f, Traffic2.GREEN));
+        assertEquals(Traffic2.RED, EnumUtils.getFirstEnum(Traffic2.class, 6, f, Traffic2.RED));
+        assertEquals(Traffic2.AMBER, EnumUtils.getFirstEnum(Traffic2.class, 0, f, Traffic2.AMBER));
+        assertEquals(Traffic2.GREEN, EnumUtils.getFirstEnum(Traffic2.class, -1, f, Traffic2.GREEN));
+        assertEquals(Traffic2.RED, EnumUtils.getFirstEnum(Traffic2.class, 0, f, Traffic2.RED));
+        assertNull(EnumUtils.getFirstEnum(Traffic2.class, 7, f, null));
+    }
+
     @Test
     public void testIsValidEnum() {
         assertTrue(EnumUtils.isValidEnum(Traffic.class, "RED"));
@@ -591,6 +601,12 @@ public void testProcessBitVectors_nullClass() {
 
 }
 
+enum Enum64 {
+    A00, A01, A02, A03, A04, A05, A06, A07, A08, A09, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22,
+    A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A40, A41, A42, A43, A44, A45,
+    A46, A47, A48, A49, A50, A51, A52, A53, A54, A55, A56, A57, A58, A59, A60, A61, A62, A63
+}
+
 enum Month {
     JAN(1), FEB(2), MAR(3), APR(4), MAY(5), JUN(6), JUL(7), AUG(8), SEP(9), OCT(10), NOV(11), DEC(12);
 
@@ -617,15 +633,21 @@ enum Traffic {
 
 enum Traffic2 {
 
-    RED("***Red***"), AMBER("**Amber**"), GREEN("*green*");
+    RED("***Red***", 1), AMBER("**Amber**", 2), GREEN("*green*", 3);
 
     final String label;
+    final int value;
 
-    Traffic2(final String label) {
+    Traffic2(final String label, final int value) {
         this.label = label;
+        this.value = value;
     }
 
     public String getLabel() {
         return label;
     }
+
+    public int getValue() {
+        return value;
+    }
 }