From 2cd6064195da817d2c34b64f19d4c6d630efbc4a Mon Sep 17 00:00:00 2001
From: Jonathan Turner Eagles <jeagles@apache.org>
Date: Tue, 20 Aug 2013 21:53:38 +0000
Subject: [PATCH] HADOOP-9686. Easy access to final parameters in Configuration
 (Jason Lowe via jeagles)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1515984 13f79535-47bb-0310-9956-ffa450edef68
---
 .../hadoop-common/CHANGES.txt                  |  3 +++
 .../org/apache/hadoop/conf/Configuration.java  |  9 +++++++++
 .../apache/hadoop/conf/TestConfiguration.java  | 18 +++++++++++++++++-
 3 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/hadoop-common-project/hadoop-common/CHANGES.txt b/hadoop-common-project/hadoop-common/CHANGES.txt
index 02ff55b5ab..5ccfc1d56e 100644
--- a/hadoop-common-project/hadoop-common/CHANGES.txt
+++ b/hadoop-common-project/hadoop-common/CHANGES.txt
@@ -2074,6 +2074,9 @@ Release 0.23.10 - UNRELEASED
 
   IMPROVEMENTS
 
+    HADOOP-9686. Easy access to final parameters in Configuration (Jason Lowe
+    via jeagles)
+
   OPTIMIZATIONS
 
   BUG FIXES
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/conf/Configuration.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/conf/Configuration.java
index 71d5ce4320..8a4cc00f56 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/conf/Configuration.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/conf/Configuration.java
@@ -1918,6 +1918,15 @@ public Reader getConfResourceAsReader(String name) {
     }
   }
 
+  /**
+   * Get the set of parameters marked final.
+   *
+   * @return final parameter set.
+   */
+  public Set<String> getFinalParameters() {
+    return new HashSet<String>(finalParameters);
+  }
+
   protected synchronized Properties getProps() {
     if (properties == null) {
       properties = new Properties();
diff --git a/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/conf/TestConfiguration.java b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/conf/TestConfiguration.java
index 3bb211c54e..87ebb61f49 100644
--- a/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/conf/TestConfiguration.java
+++ b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/conf/TestConfiguration.java
@@ -1272,7 +1272,23 @@ public void testGetClassByNameOrNull() throws Exception {
    Class<?> clazz = config.getClassByNameOrNull("java.lang.Object");
    assertNotNull(clazz);
   }
-  
+
+  public void testGetFinalParameters() throws Exception {
+    out=new BufferedWriter(new FileWriter(CONFIG));
+    startConfig();
+    declareProperty("my.var", "x", "x", true);
+    endConfig();
+    Path fileResource = new Path(CONFIG);
+    Configuration conf = new Configuration();
+    Set<String> finalParameters = conf.getFinalParameters();
+    assertFalse("my.var already exists", finalParameters.contains("my.var"));
+    conf.addResource(fileResource);
+    assertEquals("my.var is undefined", "x", conf.get("my.var"));
+    assertFalse("finalparams not copied", finalParameters.contains("my.var"));
+    finalParameters = conf.getFinalParameters();
+    assertTrue("my.var is not final", finalParameters.contains("my.var"));
+  }
+
   public static void main(String[] argv) throws Exception {
     junit.textui.TestRunner.main(new String[]{
       TestConfiguration.class.getName()