backport ADOOP-9487 Deprecation warnings in Configuration to go to own log

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1524009 13f79535-47bb-0310-9956-ffa450edef68

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -70,6 +70,9 @@ Release 2.1.1-beta - 2013-09-23
     HADOOP-9962. in order to avoid dependency divergence within Hadoop itself 
     lets enable DependencyConvergence. (rvs via tucu)
 
+    HADOOP-9487 Deprecation warnings in Configuration should go to their
+    own log or otherwise be suppressible (Chu Tong via stevel)
+
   OPTIMIZATIONS
 
   BUG FIXES

hadoop-common-project/hadoop-common/src/main/conf/log4j.properties

@@ -130,6 +130,13 @@ log4j.appender.DRFAS.layout=org.apache.log4j.PatternLayout
 log4j.appender.DRFAS.layout.ConversionPattern=%d{ISO8601} %p %c: %m%n
 log4j.appender.DRFAS.DatePattern=.yyyy-MM-dd
 
+#
+# hadoop configuration logging
+#
+
+# Uncomment the following line to turn off configuration deprecation warnings.
+# log4j.logger.org.apache.hadoop.conf.Configuration.deprecation=WARN
+
 #
 # hdfs audit logging
 #

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/conf/Configuration.java

@@ -153,6 +153,10 @@ import com.google.common.base.Preconditions;
  * will be resolved to another property in this Configuration, while
  * <tt>${<i>user.name</i>}</tt> would then ordinarily be resolved to the value
  * of the System property with that name.
+ * By default, warnings will be given to any deprecated configuration 
+ * parameters and these are suppressible by configuring
+ * <tt>log4j.logger.org.apache.hadoop.conf.Configuration.deprecation</tt> in
+ * log4j.properties file.
  */
 @InterfaceAudience.Public
 @InterfaceStability.Stable
@@ -161,6 +165,9 @@ public class Configuration implements Iterable<Map.Entry<String,String>>,
   private static final Log LOG =
     LogFactory.getLog(Configuration.class);
 
+  private static final Log LOG_DEPRECATION =
+    LogFactory.getLog("org.apache.hadoop.conf.Configuration.deprecation");
+
   private boolean quietmode = true;
   
   private static class Resource {
@@ -830,7 +837,7 @@ public class Configuration implements Iterable<Map.Entry<String,String>>,
   private void warnOnceIfDeprecated(String name) {
     DeprecatedKeyInfo keyInfo = deprecatedKeyMap.get(name);
     if (keyInfo != null && !keyInfo.accessed) {
-      LOG.warn(keyInfo.getWarningMessage(name));
+      LOG_DEPRECATION.info(keyInfo.getWarningMessage(name));
     }
   }