From 3200b2ec588dfa5c50f1ec6192ff93ab9187f82d Mon Sep 17 00:00:00 2001
From: Christopher Douglas <cdouglas@apache.org>
Date: Mon, 20 Jul 2009 22:58:21 +0000
Subject: [PATCH] HADOOP-6161. Add get/setEnum methods to Configuration.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@796052 13f79535-47bb-0310-9956-ffa450edef68
---
 CHANGES.txt                                   |  2 ++
 .../org/apache/hadoop/conf/Configuration.java | 24 +++++++++++++++++++
 .../apache/hadoop/conf/TestConfiguration.java | 17 +++++++++++++
 3 files changed, 43 insertions(+)

diff --git a/CHANGES.txt b/CHANGES.txt
index 67d4a085a67..e841f83a1d6 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -480,6 +480,8 @@ Trunk (unreleased changes)
 
     HADOOP-6146. Upgrade to JetS3t version 0.7.1. (tomwhite)
 
+    HADOOP-6161. Add get/setEnum methods to Configuration. (cdouglas)
+
   OPTIMIZATIONS
 
     HADOOP-5595. NameNode does not need to run a replicator to choose a
diff --git a/src/java/org/apache/hadoop/conf/Configuration.java b/src/java/org/apache/hadoop/conf/Configuration.java
index 16958186ee1..fedf5e62f33 100644
--- a/src/java/org/apache/hadoop/conf/Configuration.java
+++ b/src/java/org/apache/hadoop/conf/Configuration.java
@@ -595,6 +595,30 @@ public void setBooleanIfUnset(String name, boolean value) {
     setIfUnset(name, Boolean.toString(value));
   }
 
+  /**
+   * Set the value of the <code>name</code> property to the given type. This
+   * is equivalent to <code>set(&lt;name&gt;, value.toString())</code>.
+   * @param name property name
+   * @param value new value
+   */
+  public <T extends Enum<T>> void setEnum(String name, T value) {
+    set(name, value.toString());
+  }
+
+  /**
+   * Return value matching this enumerated type.
+   * @param name Property name
+   * @param defaultValue Value returned if no mapping exists
+   * @throws IllegalArgumentException If mapping is illegal for the type
+   * provided
+   */
+  public <T extends Enum<T>> T getEnum(String name, T defaultValue) {
+    final String val = get(name);
+    return null == val
+      ? defaultValue
+      : Enum.valueOf(defaultValue.getDeclaringClass(), val);
+  }
+
   /**
    * A class that represents a set of positive integer ranges. It parses 
    * strings of the form: "2-3,5,7-" where ranges are separated by comma and 
diff --git a/src/test/core/org/apache/hadoop/conf/TestConfiguration.java b/src/test/core/org/apache/hadoop/conf/TestConfiguration.java
index e509fd34641..03683880409 100644
--- a/src/test/core/org/apache/hadoop/conf/TestConfiguration.java
+++ b/src/test/core/org/apache/hadoop/conf/TestConfiguration.java
@@ -327,6 +327,23 @@ public void testIntegerValues() throws IOException{
     assertEquals(-20, conf.getLong("test.int3", 0));
   }
 	
+  enum Dingo { FOO, BAR };
+  enum Yak { RAB, FOO };
+  public void testEnum() throws IOException {
+    Configuration conf = new Configuration();
+    conf.setEnum("test.enum", Dingo.FOO);
+    assertSame(Dingo.FOO, conf.getEnum("test.enum", Dingo.BAR));
+    assertSame(Yak.FOO, conf.getEnum("test.enum", Yak.RAB));
+    boolean fail = false;
+    try {
+      conf.setEnum("test.enum", Dingo.BAR);
+      Yak y = conf.getEnum("test.enum", Yak.FOO);
+    } catch (IllegalArgumentException e) {
+      fail = true;
+    }
+    assertTrue(fail);
+  }
+
   public void testReload() throws IOException {
     out=new BufferedWriter(new FileWriter(CONFIG));
     startConfig();