refactor case insensitive enum parsing

core/src/main/java/org/apache/spark/status/api/ApplicationStatus.java

@@ -25,20 +25,8 @@ public enum ApplicationStatus {
     COMPLETED,
     RUNNING;
 
-    private static String VALID_VALUES = Joiner.on(", ").join(
-            Arrays.asList(values()));
-
     public static ApplicationStatus fromString(String str) {
-        if (str == null) {
-            return null;
-        }
-        for (ApplicationStatus status: values()) {
-            if (status.name().equalsIgnoreCase(str))
-                return status;
-        }
-        throw new IllegalArgumentException(
-                String.format("Illegal type='%s'. Supported type values: %s",
-                        str, VALID_VALUES));
+        return EnumUtil.parseIgnoreCase(ApplicationStatus.class, str);
     }
 
 }

core/src/main/java/org/apache/spark/status/api/EnumUtil.java

@@ -0,0 +1,38 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.spark.status.api;
+
+import com.google.common.base.Joiner;
+
+import java.util.Arrays;
+
+public class EnumUtil {
+    public static <E extends Enum<E>> E parseIgnoreCase(Class<E> clz, String str) {
+        E[] constants = clz.getEnumConstants();
+        if (str == null) {
+            return null;
+        }
+        for (E e: constants) {
+            if (e.name().equalsIgnoreCase(str))
+                return e;
+        }
+        throw new IllegalArgumentException(
+                String.format("Illegal type='%s'. Supported type values: %s",
+                        str, Joiner.on(", ").join(
+                                Arrays.asList(constants))));
+    }
+}

core/src/main/java/org/apache/spark/status/api/StageStatus.java

@@ -17,29 +17,13 @@
 
 package org.apache.spark.status.api;
 
-import com.google.common.base.Joiner;
-
-import java.util.Arrays;
-
 public enum StageStatus {
     Active,
     Complete,
     Failed,
     Pending;
 
-    private static String VALID_VALUES = Joiner.on(", ").join(
-            Arrays.asList(values()));
-
     public static StageStatus fromString(String str) {
-        if (str == null) {
-            return null;
-        }
-        for (StageStatus status: values()) {
-            if (status.name().equalsIgnoreCase(str))
-                return status;
-        }
-        throw new IllegalArgumentException(
-                String.format("Illegal type='%s'. Supported type values: %s",
-                        str, VALID_VALUES));
+        return EnumUtil.parseIgnoreCase(StageStatus.class, str);
     }
 }