Fix so that close() throws IOException, so that classes which override

this method can throw IOException, as specified in the Closeable
interface.  Also add the Apache license (which must be in every file)
and add a bit more javadoc.


git-svn-id: https://svn.apache.org/repos/asf/lucene/hadoop/trunk@391364 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -1,17 +1,38 @@
+/**
+ * Copyright 2006 The Apache Software Foundation
+ *
+ * Licensed 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.mapred;
 
+import java.io.IOException;
+
 import org.apache.hadoop.io.Closeable;
 import org.apache.hadoop.mapred.JobConfigurable;
 
-/**
- * A class to implement the trivial close and configure methods.
+/** Base class for {@link Mapper} and {@link Reducer} implementations.
+ * Provides default implementations for a few methods.
+ *
  * @author Owen O'Malley
  */
 public class MapReduceBase implements Closeable, JobConfigurable {
 
-  public void close() {
+  /** Default implementation that does nothing. */
+  public void close() throws IOException {
   }
 
+  /** Default implementation that does nothing. */
   public void configure(JobConf job) {
   }