THRIFT-949. java: Modify the TEnum interface so it defines a method similar to findByValue
This patch adds a new helper class that makes it easier to get instances of generic TEnum descendents by value.
Patch: Mathias Herberts
git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@1028051 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/lib/java/src/org/apache/thrift/TEnumHelper.java b/lib/java/src/org/apache/thrift/TEnumHelper.java
new file mode 100644
index 0000000..c17d661
--- /dev/null
+++ b/lib/java/src/org/apache/thrift/TEnumHelper.java
@@ -0,0 +1,57 @@
+/*
+ * 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.thrift;
+
+import java.lang.InstantiationException;
+import java.lang.NoSuchMethodException;
+import java.lang.IllegalAccessException;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+
+/**
+ * Utility class with static methods for interacting with TEnum
+ */
+public class TEnumHelper {
+
+ /**
+ * Given a TEnum class and integer value, this method will return
+ * the associated constant from the given TEnum class.
+ * This method MUST be modified should the name of the 'findByValue' method
+ * change.
+ *
+ * @param enumClass TEnum from which to return a matching constant.
+ * @param value Value for which to return the constant.
+ *
+ * @return The constant in 'enumClass' whose value is 'value' or null if
+ * something went wrong.
+ */
+ public static TEnum getByValue(Class<? extends TEnum> enumClass, int value) {
+ try {
+ Method method = enumClass.getMethod("findByValue", int.class);
+ return (TEnum) method.invoke(null, value);
+ } catch (NoSuchMethodException nsme) {
+ return null;
+ } catch (IllegalAccessException iae) {
+ return null;
+ } catch (InvocationTargetException ite) {
+ return null;
+ }
+ }
+}
diff --git a/lib/java/test/org/apache/thrift/TestTEnumHelper.java b/lib/java/test/org/apache/thrift/TestTEnumHelper.java
new file mode 100644
index 0000000..e2cca40
--- /dev/null
+++ b/lib/java/test/org/apache/thrift/TestTEnumHelper.java
@@ -0,0 +1,41 @@
+/*
+ * 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.thrift;
+
+import thrift.test.Numberz;
+
+import junit.framework.TestCase;
+
+public class TestTEnumHelper extends TestCase {
+
+ public void testGetByValue_ValidValues() {
+ for (Numberz n: Numberz.values()) {
+ int value = n.getValue();
+ assertEquals(n, TEnumHelper.getByValue(Numberz.class, value));
+ }
+ }
+
+ public void testGetByValue_InvalidValue() {
+ assertEquals(null, TEnumHelper.getByValue(Numberz.class, 0));
+ }
+
+ public void testGetByValue_InvalidClass() {
+ assertEquals(null, TEnumHelper.getByValue(TEnum.class, 0));
+ }
+}