[SPARK-21671][CORE] Move kvstore to "util" sub-package, add private annotation.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #18886 from vanzin/SPARK-21671.

common/kvstore/src/main/java/org/apache/spark/util/kvstore/ArrayWrappers.java

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark.kvstore;
+package org.apache.spark.util.kvstore;
 
 import java.util.Arrays;
 

common/kvstore/src/main/java/org/apache/spark/util/kvstore/InMemoryStore.java

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark.kvstore;
+package org.apache.spark.util.kvstore;
 
 import java.util.ArrayList;
 import java.util.Collection;

common/kvstore/src/main/java/org/apache/spark/util/kvstore/KVIndex.java

@@ -15,13 +15,15 @@
  * limitations under the License.
  */
 
-package org.apache.spark.kvstore;
+package org.apache.spark.util.kvstore;
 
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
+import org.apache.spark.annotation.Private;
+
 /**
  * Tags a field to be indexed when storing an object.
  *
@@ -46,6 +48,7 @@ import java.lang.annotation.Target;
  * of those values.
  * </p>
  */
+@Private
 @Retention(RetentionPolicy.RUNTIME)
 @Target({ElementType.FIELD, ElementType.METHOD})
 public @interface KVIndex {

common/kvstore/src/main/java/org/apache/spark/util/kvstore/KVStore.java

@@ -15,10 +15,12 @@
  * limitations under the License.
  */
 
-package org.apache.spark.kvstore;
+package org.apache.spark.util.kvstore;
 
 import java.io.Closeable;
 
+import org.apache.spark.annotation.Private;
+
 /**
  * Abstraction for a local key/value store for storing app data.
  *
@@ -59,6 +61,7 @@ import java.io.Closeable;
  * KVStore instances are thread-safe for both reads and writes.
  * </p>
  */
+@Private
 public interface KVStore extends Closeable {
 
   /**

common/kvstore/src/main/java/org/apache/spark/util/kvstore/KVStoreIterator.java

@@ -15,11 +15,13 @@
  * limitations under the License.
  */
 
-package org.apache.spark.kvstore;
+package org.apache.spark.util.kvstore;
 
 import java.util.Iterator;
 import java.util.List;
 
+import org.apache.spark.annotation.Private;
+
 /**
  * An iterator for KVStore.
  *
@@ -28,6 +30,7 @@ import java.util.List;
  * explicitly close iterators after they're used.
  * </p>
  */
+@Private
 public interface KVStoreIterator<T> extends Iterator<T>, AutoCloseable {
 
   /**

common/kvstore/src/main/java/org/apache/spark/util/kvstore/KVStoreSerializer.java

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark.kvstore;
+package org.apache.spark.util.kvstore;
 
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
@@ -25,6 +25,8 @@ import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 
+import org.apache.spark.annotation.Private;
+
 /**
  * Serializer used to translate between app-defined types and the LevelDB store.
  *
@@ -33,6 +35,7 @@ import com.fasterxml.jackson.databind.ObjectMapper;
  * and integers to be written as values directly, which will be written as UTF-8 strings.
  * </p>
  */
+@Private
 public class KVStoreSerializer {
 
   /**

common/kvstore/src/main/java/org/apache/spark/util/kvstore/KVStoreView.java

@@ -15,10 +15,12 @@
  * limitations under the License.
  */
 
-package org.apache.spark.kvstore;
+package org.apache.spark.util.kvstore;
 
 import com.google.common.base.Preconditions;
 
+import org.apache.spark.annotation.Private;
+
 /**
  * A configurable view that allows iterating over values in a {@link KVStore}.
  *
@@ -33,6 +35,7 @@ import com.google.common.base.Preconditions;
  * to be closed explicitly unless all elements are read.
  * </p>
  */
+@Private
 public abstract class KVStoreView<T> implements Iterable<T> {
 
   final Class<T> type;

common/kvstore/src/main/java/org/apache/spark/util/kvstore/KVTypeInfo.java

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark.kvstore;
+package org.apache.spark.util.kvstore;
 
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
@@ -25,9 +25,12 @@ import java.util.stream.Stream;
 
 import com.google.common.base.Preconditions;
 
+import org.apache.spark.annotation.Private;
+
 /**
  * Wrapper around types managed in a KVStore, providing easy access to their indexed fields.
  */
+@Private
 public class KVTypeInfo {
 
   private final Class<?> type;

common/kvstore/src/main/java/org/apache/spark/util/kvstore/LevelDB.java

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark.kvstore;
+package org.apache.spark.util.kvstore;
 
 import java.io.File;
 import java.io.IOException;
@@ -36,9 +36,12 @@ import org.iq80.leveldb.DB;
 import org.iq80.leveldb.Options;
 import org.iq80.leveldb.WriteBatch;
 
+import org.apache.spark.annotation.Private;
+
 /**
  * Implementation of KVStore that uses LevelDB as the underlying data store.
  */
+@Private
 public class LevelDB implements KVStore {
 
   @VisibleForTesting

common/kvstore/src/main/java/org/apache/spark/util/kvstore/LevelDBIterator.java

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark.kvstore;
+package org.apache.spark.util.kvstore;
 
 import java.io.IOException;
 import java.util.ArrayList;

common/kvstore/src/main/java/org/apache/spark/util/kvstore/LevelDBTypeInfo.java

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark.kvstore;
+package org.apache.spark.util.kvstore;
 
 import java.lang.reflect.Array;
 import java.util.Collection;

common/kvstore/src/main/java/org/apache/spark/util/kvstore/UnsupportedStoreVersionException.java

@@ -15,13 +15,16 @@
  * limitations under the License.
  */
 
-package org.apache.spark.kvstore;
+package org.apache.spark.util.kvstore;
 
 import java.io.IOException;
 
+import org.apache.spark.annotation.Private;
+
 /**
  * Exception thrown when the store implementation is not compatible with the underlying data.
  */
+@Private
 public class UnsupportedStoreVersionException extends IOException {
 
 }

common/kvstore/src/test/java/org/apache/spark/util/kvstore/ArrayKeyIndexType.java

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark.kvstore;
+package org.apache.spark.util.kvstore;
 
 import java.util.Arrays;
 

common/kvstore/src/test/java/org/apache/spark/util/kvstore/ArrayWrappersSuite.java

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark.kvstore;
+package org.apache.spark.util.kvstore;
 
 import org.junit.Test;
 import static org.junit.Assert.*;

common/kvstore/src/test/java/org/apache/spark/util/kvstore/CustomType1.java

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark.kvstore;
+package org.apache.spark.util.kvstore;
 
 import com.google.common.base.Objects;
 

common/kvstore/src/test/java/org/apache/spark/util/kvstore/DBIteratorSuite.java

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark.kvstore;
+package org.apache.spark.util.kvstore;
 
 import java.util.Arrays;
 import java.util.ArrayList;

common/kvstore/src/test/java/org/apache/spark/util/kvstore/InMemoryIteratorSuite.java

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark.kvstore;
+package org.apache.spark.util.kvstore;
 
 public class InMemoryIteratorSuite extends DBIteratorSuite {
 

common/kvstore/src/test/java/org/apache/spark/util/kvstore/InMemoryStoreSuite.java

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark.kvstore;
+package org.apache.spark.util.kvstore;
 
 import java.util.NoSuchElementException;
 

common/kvstore/src/test/java/org/apache/spark/util/kvstore/LevelDBBenchmark.java

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark.kvstore;
+package org.apache.spark.util.kvstore;
 
 import java.io.File;
 import java.util.ArrayList;

common/kvstore/src/test/java/org/apache/spark/util/kvstore/LevelDBIteratorSuite.java

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark.kvstore;
+package org.apache.spark.util.kvstore;
 
 import java.io.File;
 

common/kvstore/src/test/java/org/apache/spark/util/kvstore/LevelDBSuite.java

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark.kvstore;
+package org.apache.spark.util.kvstore;
 
 import java.io.File;
 import java.util.Arrays;

common/kvstore/src/test/java/org/apache/spark/util/kvstore/LevelDBTypeInfoSuite.java

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark.kvstore;
+package org.apache.spark.util.kvstore;
 
 import static java.nio.charset.StandardCharsets.UTF_8;