Author: shv
Date: Mon Oct 10 00:33:50 2011
New Revision: 1180750
URL: http://svn.apache.org/viewvc?rev=1180750&view=rev
Log:
MAPREDUCE-3138. Add a utility to help applications bridge changes in Context
Objects APIs due to MAPREDUCE-954. Contributed by omalley.
Added:
hadoop/common/branches/branch-0.22/mapreduce/src/java/org/apache/hadoop/mapreduce/ContextFactory.java
(with props)
Modified:
hadoop/common/branches/branch-0.22/mapreduce/CHANGES.txt
Modified: hadoop/common/branches/branch-0.22/mapreduce/CHANGES.txt
URL:
http://svn.apache.org/viewvc/hadoop/common/branches/branch-0.22/mapreduce/CHANGES.txt?rev=1180750&r1=1180749&r2=1180750&view=diff
==============================================================================
--- hadoop/common/branches/branch-0.22/mapreduce/CHANGES.txt (original)
+++ hadoop/common/branches/branch-0.22/mapreduce/CHANGES.txt Mon Oct 10
00:33:50 2011
@@ -225,6 +225,9 @@ Release 0.22.0 - Unreleased
MAPREDUCE-3039. Upgrade to Avro 1.5.3. (Joep Rottinghuis via shv)
+ MAPREDUCE-3138. Add a utility to help applications bridge changes in
+ Context Objects APIs due to MAPREDUCE-954. (omalley via acmurthy)
+
OPTIMIZATIONS
MAPREDUCE-1354. Enhancements to JobTracker for better performance and
Added:
hadoop/common/branches/branch-0.22/mapreduce/src/java/org/apache/hadoop/mapreduce/ContextFactory.java
URL:
http://svn.apache.org/viewvc/hadoop/common/branches/branch-0.22/mapreduce/src/java/org/apache/hadoop/mapreduce/ContextFactory.java?rev=1180750&view=auto
==============================================================================
---
hadoop/common/branches/branch-0.22/mapreduce/src/java/org/apache/hadoop/mapreduce/ContextFactory.java
(added)
+++
hadoop/common/branches/branch-0.22/mapreduce/src/java/org/apache/hadoop/mapreduce/ContextFactory.java
Mon Oct 10 00:33:50 2011
@@ -0,0 +1,241 @@
+/**
+ * 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.mapreduce;
+
+import java.io.IOException;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Field;
+import java.lang.reflect.InvocationTargetException;
+
+import org.apache.hadoop.conf.Configuration;
+
+/**
+ * A factory to allow applications to deal with inconsistencies between
+ * MapReduce Context Objects API between hadoop-0.20 and later versions.
+ */
+public class ContextFactory {
+
+ private static final Constructor<?> JOB_CONTEXT_CONSTRUCTOR;
+ private static final Constructor<?> TASK_CONTEXT_CONSTRUCTOR;
+ private static final Constructor<?> MAP_CONTEXT_CONSTRUCTOR;
+ private static final Constructor<?> MAP_CONTEXT_IMPL_CONSTRUCTOR;
+ private static final boolean useV21;
+
+ private static final Field REPORTER_FIELD;
+ private static final Field READER_FIELD;
+ private static final Field WRITER_FIELD;
+ private static final Field OUTER_MAP_FIELD;
+ private static final Field WRAPPED_CONTEXT_FIELD;
+
+ static {
+ boolean v21 = true;
+ final String PACKAGE = "org.apache.hadoop.mapreduce";
+ try {
+ Class.forName(PACKAGE + ".task.JobContextImpl");
+ } catch (ClassNotFoundException cnfe) {
+ v21 = false;
+ }
+ useV21 = v21;
+ Class<?> jobContextCls;
+ Class<?> taskContextCls;
+ Class<?> taskIOContextCls;
+ Class<?> mapCls;
+ Class<?> mapContextCls;
+ Class<?> innerMapContextCls;
+ try {
+ if (v21) {
+ jobContextCls =
+ Class.forName(PACKAGE+".task.JobContextImpl");
+ taskContextCls =
+ Class.forName(PACKAGE+".task.TaskAttemptContextImpl");
+ taskIOContextCls =
+ Class.forName(PACKAGE+".task.TaskInputOutputContextImpl");
+ mapContextCls = Class.forName(PACKAGE + ".task.MapContextImpl");
+ mapCls = Class.forName(PACKAGE + ".lib.map.WrappedMapper");
+ innerMapContextCls =
+ Class.forName(PACKAGE+".lib.map.WrappedMapper$Context");
+ } else {
+ jobContextCls =
+ Class.forName(PACKAGE+".JobContext");
+ taskContextCls =
+ Class.forName(PACKAGE+".TaskAttemptContext");
+ taskIOContextCls =
+ Class.forName(PACKAGE+".TaskInputOutputContext");
+ mapContextCls = Class.forName(PACKAGE + ".MapContext");
+ mapCls = Class.forName(PACKAGE + ".Mapper");
+ innerMapContextCls =
+ Class.forName(PACKAGE+".Mapper$Context");
+ }
+ } catch (ClassNotFoundException e) {
+ throw new IllegalArgumentException("Can't find class", e);
+ }
+ try {
+ JOB_CONTEXT_CONSTRUCTOR =
+ jobContextCls.getConstructor(Configuration.class, JobID.class);
+ JOB_CONTEXT_CONSTRUCTOR.setAccessible(true);
+ TASK_CONTEXT_CONSTRUCTOR =
+ taskContextCls.getConstructor(Configuration.class,
+ TaskAttemptID.class);
+ TASK_CONTEXT_CONSTRUCTOR.setAccessible(true);
+ if (useV21) {
+ MAP_CONTEXT_CONSTRUCTOR =
+ innerMapContextCls.getConstructor(mapCls,
+ MapContext.class);
+ MAP_CONTEXT_IMPL_CONSTRUCTOR =
+ mapContextCls.getDeclaredConstructor(Configuration.class,
+ TaskAttemptID.class,
+ RecordReader.class,
+ RecordWriter.class,
+ OutputCommitter.class,
+ StatusReporter.class,
+ InputSplit.class);
+ MAP_CONTEXT_IMPL_CONSTRUCTOR.setAccessible(true);
+ WRAPPED_CONTEXT_FIELD =
+ innerMapContextCls.getDeclaredField("mapContext");
+ WRAPPED_CONTEXT_FIELD.setAccessible(true);
+ } else {
+ MAP_CONTEXT_CONSTRUCTOR =
+ innerMapContextCls.getConstructor(mapCls,
+ Configuration.class,
+ TaskAttemptID.class,
+ RecordReader.class,
+ RecordWriter.class,
+ OutputCommitter.class,
+ StatusReporter.class,
+ InputSplit.class);
+ MAP_CONTEXT_IMPL_CONSTRUCTOR = null;
+ WRAPPED_CONTEXT_FIELD = null;
+ }
+ MAP_CONTEXT_CONSTRUCTOR.setAccessible(true);
+ REPORTER_FIELD = taskIOContextCls.getDeclaredField("reporter");
+ REPORTER_FIELD.setAccessible(true);
+ READER_FIELD = mapContextCls.getDeclaredField("reader");
+ READER_FIELD.setAccessible(true);
+ WRITER_FIELD = taskIOContextCls.getDeclaredField("output");
+ WRITER_FIELD.setAccessible(true);
+ OUTER_MAP_FIELD = innerMapContextCls.getDeclaredField("this$0");
+ OUTER_MAP_FIELD.setAccessible(true);
+ } catch (SecurityException e) {
+ throw new IllegalArgumentException("Can't run constructor ", e);
+ } catch (NoSuchMethodException e) {
+ throw new IllegalArgumentException("Can't find constructor ", e);
+ } catch (NoSuchFieldException e) {
+ throw new IllegalArgumentException("Can't find field ", e);
+ }
+ }
+
+ /**
+ * Clone a job or task attempt context with a new configuration.
+ * @param original the original context
+ * @param conf the new configuration
+ * @return a new context object
+ * @throws InterruptedException
+ * @throws IOException
+ */
+ @SuppressWarnings("unchecked")
+ public static JobContext cloneContext(JobContext original,
+ Configuration conf
+ ) throws IOException,
+ InterruptedException {
+ try {
+ if (original instanceof MapContext<?,?,?,?>) {
+ return cloneMapContext((Mapper.Context) original, conf, null, null);
+ } else if (original instanceof ReduceContext<?,?,?,?>) {
+ throw new IllegalArgumentException("can't clone ReduceContext");
+ } else if (original instanceof TaskAttemptContext) {
+ TaskAttemptContext spec = (TaskAttemptContext) original;
+ return (JobContext)
+ TASK_CONTEXT_CONSTRUCTOR.newInstance(conf, spec.getTaskAttemptID());
+ } else {
+ return (JobContext)
+ JOB_CONTEXT_CONSTRUCTOR.newInstance(conf, original.getJobID());
+ }
+ } catch (InstantiationException e) {
+ throw new IllegalArgumentException("Can't clone object", e);
+ } catch (IllegalAccessException e) {
+ throw new IllegalArgumentException("Can't clone object", e);
+ } catch (InvocationTargetException e) {
+ throw new IllegalArgumentException("Can't clone object", e);
+ }
+ }
+
+ /**
+ * Copy a mapper context, optionally replacing the input and output.
+ * @param <K1> input key type
+ * @param <V1> input value type
+ * @param <K2> output key type
+ * @param <V2> output value type
+ * @param context the context to clone
+ * @param conf a new configuration
+ * @param reader Reader to read from. Null means to clone from context.
+ * @param writer Writer to write to. Null means to clone from context.
+ * @return a new context. it will not be the same class as the original.
+ * @throws IOException
+ * @throws InterruptedException
+ */
+ @SuppressWarnings("unchecked")
+ public static <K1,V1,K2,V2> Mapper<K1,V1,K2,V2>.Context
+ cloneMapContext(MapContext<K1,V1,K2,V2> context,
+ Configuration conf,
+ RecordReader<K1,V1> reader,
+ RecordWriter<K2,V2> writer
+ ) throws IOException, InterruptedException {
+ try {
+ // get the outer object pointer
+ Object outer = OUTER_MAP_FIELD.get(context);
+ // if it is a wrapped 21 context, unwrap it
+ if ("org.apache.hadoop.mapreduce.lib.map.WrappedMapper$Context".equals
+ (context.getClass().getName())) {
+ context = (MapContext<K1,V1,K2,V2>) WRAPPED_CONTEXT_FIELD.get(context);
+ }
+ // if the reader or writer aren't given, use the same ones
+ if (reader == null) {
+ reader = (RecordReader<K1,V1>) READER_FIELD.get(context);
+ }
+ if (writer == null) {
+ writer = (RecordWriter<K2,V2>) WRITER_FIELD.get(context);
+ }
+ if (useV21) {
+ Object basis =
+ MAP_CONTEXT_IMPL_CONSTRUCTOR.newInstance(conf,
+ context.getTaskAttemptID(),
+ reader, writer,
+
context.getOutputCommitter(),
+ REPORTER_FIELD.get(context),
+ context.getInputSplit());
+ return (Mapper.Context)
+ MAP_CONTEXT_CONSTRUCTOR.newInstance(outer, basis);
+ } else {
+ return (Mapper.Context)
+ MAP_CONTEXT_CONSTRUCTOR.newInstance(outer,
+ conf, context.getTaskAttemptID(),
+ reader, writer,
+ context.getOutputCommitter(),
+ REPORTER_FIELD.get(context),
+ context.getInputSplit());
+ }
+ } catch (IllegalAccessException e) {
+ throw new IllegalArgumentException("Can't access field", e);
+ } catch (InstantiationException e) {
+ throw new IllegalArgumentException("Can't create object", e);
+ } catch (InvocationTargetException e) {
+ throw new IllegalArgumentException("Can't invoke constructor", e);
+ }
+ }
+}
Propchange:
hadoop/common/branches/branch-0.22/mapreduce/src/java/org/apache/hadoop/mapreduce/ContextFactory.java
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