From a6ce16470dda427380b41e930ed59e028bdb7615 Mon Sep 17 00:00:00 2001
From: Bryan Duxbury <bryanduxbury@apache.org>
Date: Wed, 27 Oct 2010 17:54:10 +0000
Subject: [PATCH] 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
---
 .../src/org/apache/thrift/TEnumHelper.java    | 57 +++++++++++++++++++
 .../org/apache/thrift/TestTEnumHelper.java    | 41 +++++++++++++
 2 files changed, 98 insertions(+)
 create mode 100644 lib/java/src/org/apache/thrift/TEnumHelper.java
 create mode 100644 lib/java/test/org/apache/thrift/TestTEnumHelper.java

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 00000000..c17d661c
--- /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 00000000..e2cca403
--- /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));
+  }
+}
-- 
2.17.1