HDFS-14221. Replace Guava Optional with Java Optional. Contributed by Arpit Agarwal.

(cherry picked from commit 1ff658b2ef3fb933897712c728bc628f3f44bded)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/checker/AsyncChecker.java

@@ -18,7 +18,7 @@
 
 package org.apache.hadoop.hdfs.server.datanode.checker;
 
-import com.google.common.base.Optional;
+import java.util.Optional;
 import com.google.common.util.concurrent.ListenableFuture;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/checker/DatasetVolumeChecker.java

@@ -19,7 +19,6 @@
 package org.apache.hadoop.hdfs.server.datanode.checker;
 
 import com.google.common.annotations.VisibleForTesting;
-import com.google.common.base.Optional;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.Sets;
 import com.google.common.util.concurrent.FutureCallback;
@@ -44,6 +43,7 @@ import javax.annotation.Nullable;
 import java.nio.channels.ClosedChannelException;
 import java.util.Collections;
 import java.util.HashSet;
+import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutionException;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/checker/StorageLocationChecker.java

@@ -20,7 +20,6 @@ package org.apache.hadoop.hdfs.server.datanode.checker;
 
 import static org.apache.hadoop.hdfs.DFSConfigKeys.*;
 
-import com.google.common.base.Optional;
 import com.google.common.collect.Maps;
 import com.google.common.util.concurrent.ListenableFuture;
 import com.google.common.util.concurrent.ThreadFactoryBuilder;
@@ -47,6 +46,7 @@ import java.util.HashSet;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Executors;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/checker/ThrottledAsyncChecker.java

@@ -18,7 +18,6 @@
 
 package org.apache.hadoop.hdfs.server.datanode.checker;
 
-import com.google.common.base.Optional;
 import com.google.common.util.concurrent.FutureCallback;
 import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.ListenableFuture;
@@ -35,6 +34,7 @@ import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Optional;
 import java.util.WeakHashMap;
 import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutorService;
@@ -120,7 +120,7 @@ public class ThrottledAsyncChecker<K, V> implements AsyncChecker<K, V> {
   public Optional<ListenableFuture<V>> schedule(Checkable<K, V> target,
                                                 K context) {
     if (checksInProgress.containsKey(target)) {
-      return Optional.absent();
+      return Optional.empty();
     }
 
     if (completedChecks.containsKey(target)) {
@@ -130,7 +130,7 @@ public class ThrottledAsyncChecker<K, V> implements AsyncChecker<K, V> {
         LOG.debug("Skipped checking {}. Time since last check {}ms " +
                 "is less than the min gap {}ms.",
             target, msSinceLastCheck, minMsBetweenChecks);
-        return Optional.absent();
+        return Optional.empty();
       }
     }
 

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/checker/TestDatasetVolumeChecker.java

@@ -18,7 +18,6 @@
 
 package org.apache.hadoop.hdfs.server.datanode.checker;
 
-import com.google.common.base.Optional;
 import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.ListenableFuture;
 import org.apache.hadoop.hdfs.HdfsConfiguration;
@@ -40,6 +39,7 @@ import org.slf4j.LoggerFactory;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
+import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicLong;

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/checker/TestThrottledAsyncChecker.java

@@ -18,7 +18,6 @@
 
 package org.apache.hadoop.hdfs.server.datanode.checker;
 
-import com.google.common.base.Optional;
 import com.google.common.base.Supplier;
 import com.google.common.util.concurrent.ListenableFuture;
 import org.apache.hadoop.test.GenericTestUtils;
@@ -27,6 +26,7 @@ import org.junit.Test;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.util.Optional;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.ScheduledThreadPoolExecutor;

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/checker/TestThrottledAsyncCheckerTimeout.java

@@ -17,28 +17,10 @@
  */
 package org.apache.hadoop.hdfs.server.datanode.checker;
 
-import static org.mockito.Matchers.any;
-import static org.mockito.Matchers.anyObject;
-import static org.mockito.Matchers.anySet;
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.times;
-import static org.mockito.Mockito.timeout;
-import static org.mockito.Mockito.verify;
-
-import com.google.common.base.Optional;
 import com.google.common.util.concurrent.FutureCallback;
 import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.ListenableFuture;
-import org.apache.hadoop.conf.Configuration;
-import org.apache.hadoop.hdfs.DFSConfigKeys;
-import org.apache.hadoop.hdfs.HdfsConfiguration;
-import org.apache.hadoop.hdfs.LogVerificationAppender;
-import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsVolumeSpi;
 import org.apache.hadoop.util.FakeTimer;
-import org.apache.log4j.Logger;
-import org.apache.log4j.spi.LoggingEvent;
-import static org.hamcrest.CoreMatchers.is;
-import static org.junit.Assert.*;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
@@ -46,15 +28,22 @@ import org.junit.rules.TestName;
 import org.junit.rules.Timeout;
 import org.slf4j.LoggerFactory;
 
-import java.util.Set;
+import java.util.Optional;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.ScheduledThreadPoolExecutor;
-import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.concurrent.locks.ReentrantLock;
 
+import static org.hamcrest.CoreMatchers.is;
+import static org.junit.Assert.assertThat;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Matchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.timeout;
+import static org.mockito.Mockito.verify;
+
 public class TestThrottledAsyncCheckerTimeout {
   public static final org.slf4j.Logger LOG =
       LoggerFactory.getLogger(TestThrottledAsyncCheckerTimeout.class);

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestAuditLogAtDebug.java

@@ -19,7 +19,6 @@
 package org.apache.hadoop.hdfs.server.namenode;
 
 import com.google.common.base.Joiner;
-import com.google.common.base.Optional;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.apache.hadoop.conf.Configuration;
@@ -35,6 +34,8 @@ import org.junit.rules.Timeout;
 import java.net.Inet4Address;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Optional;
+
 
 import static org.mockito.Matchers.anyString;
 import static org.mockito.Mockito.*;
@@ -122,8 +123,7 @@ public class TestAuditLogAtDebug {
   
   @Test
   public void testEmptyDebugCommands() {
-    DefaultAuditLogger logger = makeSpyLogger(
-        Level.INFO, Optional.<List<String>>absent());
+    DefaultAuditLogger logger = makeSpyLogger(Level.INFO, Optional.empty());
     logDummyCommandToAuditLog(logger, DUMMY_COMMAND_1);
     logDummyCommandToAuditLog(logger, DUMMY_COMMAND_2);
     verify(logger, times(2)).logAuditMessage(anyString());