HADOOP-3730. Adds a new JobConf constructor that disables loading default configurations. Contributed by Alejandro Abdelnur.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/core/trunk@677362 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -52,6 +52,9 @@ Trunk (unreleased changes)
     bash tab completion for the bin/hadoop script. See the README file
     in the contrib directory for the installation. (Chris Smith via enis)
 
+    HADOOP-3730. Adds a new JobConf constructor that disables loading
+    default configurations. (Alejandro Abdelnur via ddas)
+
   IMPROVEMENTS
 
     HADOOP-3732. Delay intialization of datanode block verification till

src/mapred/org/apache/hadoop/mapred/JobConf.java

@@ -154,6 +154,18 @@ public class JobConf extends Configuration {
     addResource(config);
   }
 
+  /** A new map/reduce configuration where the behavior of reading from the
+   * default resources can be turned off.
+   * <p/>
+   * If the parameter {@code loadDefaults} is false, the new instance
+   * will not load resources from the default files.
+   *
+   * @param loadDefaults specifies whether to load from the default files
+   */
+  public JobConf(boolean loadDefaults) {
+    super(loadDefaults);
+  }
+
   /**
    * Get the user jar for the map-reduce job.
    * 

src/test/org/apache/hadoop/conf/TestNoDefaultsJobConf.java

@@ -0,0 +1,103 @@
+/**
+ * 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.hadoop.conf;
+
+import junit.framework.Assert;
+
+import org.apache.hadoop.mapred.*;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.fs.FileUtil;
+import org.apache.hadoop.io.LongWritable;
+import org.apache.hadoop.io.Text;
+
+import java.io.*;
+
+/**
+ * This testcase tests that a JobConf without default values submits jobs
+ * properly and the JT applies its own default values to it to make the job
+ * run properly.
+ */
+public class TestNoDefaultsJobConf extends HadoopTestCase {
+
+  public TestNoDefaultsJobConf() throws IOException {
+    super(HadoopTestCase.CLUSTER_MR, HadoopTestCase.DFS_FS, 1, 1);
+  }
+
+  public void testNoDefaults() throws Exception {
+    JobConf configuration = new JobConf();
+    assertTrue(configuration.get("hadoop.tmp.dir", null) != null);
+
+    configuration = new JobConf(false);
+    assertTrue(configuration.get("hadoop.tmp.dir", null) == null);
+
+
+    Path inDir = new Path("testing/jobconf/input");
+    Path outDir = new Path("testing/jobconf/output");
+
+    OutputStream os = getFileSystem().create(new Path(inDir, "text.txt"));
+    Writer wr = new OutputStreamWriter(os);
+    wr.write("hello\n");
+    wr.write("hello\n");
+    wr.close();
+
+    JobConf conf = new JobConf(false);
+
+    //seeding JT and NN info into non-defaults (empty jobconf)
+    conf.set("mapred.job.tracker", createJobConf().get("mapred.job.tracker"));
+    conf.set("fs.default.name", createJobConf().get("fs.default.name"));
+
+    conf.setJobName("mr");
+
+    conf.setInputFormat(TextInputFormat.class);
+
+    conf.setMapOutputKeyClass(LongWritable.class);
+    conf.setMapOutputValueClass(Text.class);
+
+    conf.setOutputFormat(TextOutputFormat.class);
+    conf.setOutputKeyClass(LongWritable.class);
+    conf.setOutputValueClass(Text.class);
+
+    conf.setMapperClass(org.apache.hadoop.mapred.lib.IdentityMapper.class);
+    conf.setReducerClass(org.apache.hadoop.mapred.lib.IdentityReducer.class);
+
+    FileInputFormat.setInputPaths(conf, inDir);
+
+    FileOutputFormat.setOutputPath(conf, outDir);
+
+    JobClient.runJob(conf);
+
+    Path[] outputFiles = FileUtil.stat2Paths(
+                           getFileSystem().listStatus(outDir,
+                           new OutputLogFilter()));
+    if (outputFiles.length > 0) {
+      InputStream is = getFileSystem().open(outputFiles[0]);
+      BufferedReader reader = new BufferedReader(new InputStreamReader(is));
+      String line = reader.readLine();
+      int counter = 0;
+      while (line != null) {
+        counter++;
+        assertTrue(line.contains("hello"));
+        line = reader.readLine();
+      }
+      reader.close();
+      assertEquals(2, counter);
+    }
+
+  }
+
+}