[JNI] Add java api and java tests for WriteBatch and WriteOptions, add put() and remove() to RocksDB.

Summary:
* Add java api for rocksdb::WriteBatch and rocksdb::WriteOptions, which are necessary components
  for running benchmark.
* Add java test for org.rocksdb.WriteBatch and org.rocksdb.WriteOptions.
* Add remove() to org.rocksdb.RocksDB, and add put() and remove() to RocksDB which take
  org.rocksdb.WriteOptions.

Test Plan: make jtest

Reviewers: haobo, sdong, dhruba

Reviewed By: sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D17373

Makefile

@@ -402,7 +402,7 @@ ldb: tools/ldb.o $(LIBOBJECTS)
 # ---------------------------------------------------------------------------
 # Jni stuff
 # ---------------------------------------------------------------------------
-JNI_NATIVE_SOURCES = ./java/rocksjni/rocksjni.cc ./java/rocksjni/options.cc
+JNI_NATIVE_SOURCES = ./java/rocksjni/rocksjni.cc ./java/rocksjni/options.cc ./java/rocksjni/write_batch.cc
 
 JAVA_INCLUDE = -I/usr/lib/jvm/java-openjdk/include/ -I/usr/lib/jvm/java-openjdk/include/linux 
 ROCKSDBJNILIB = ./java/librocksdbjni.so
@@ -415,6 +415,7 @@ endif
 jni: clean
 	OPT="-fPIC -DNDEBUG -O2" $(MAKE) $(LIBRARY) -j32
 	cd java;$(MAKE) java;
+	rm -f $(ROCKSDBJNILIB)
 	$(CXX) $(CXXFLAGS) -I./java/. $(JAVA_INCLUDE) -shared -fPIC -o $(ROCKSDBJNILIB) $(JNI_NATIVE_SOURCES) $(LIBOBJECTS) $(LDFLAGS) $(COVERAGEFLAGS)
 
 jclean:
@@ -422,7 +423,7 @@ jclean:
 	rm -f $(ROCKSDBJNILIB)
 
 jtest:
-	cd java;$(MAKE) sample;
+	cd java;$(MAKE) sample;$(MAKE) test;
 
 # ---------------------------------------------------------------------------
 #  	Platform-specific compilation

java/Makefile

@@ -1,4 +1,4 @@
-NATIVE_JAVA_CLASSES = org.rocksdb.RocksDB org.rocksdb.Options
+NATIVE_JAVA_CLASSES = org.rocksdb.RocksDB org.rocksdb.Options org.rocksdb.WriteBatch org.rocksdb.WriteBatchInternal org.rocksdb.WriteBatchTest org.rocksdb.WriteOptions
 NATIVE_INCLUDE = ./include
 ROCKSDB_JAR = rocksdbjni.jar
 
@@ -19,3 +19,6 @@ sample:
 	java -ea -Djava.library.path=.:../ -cp ".:./*" RocksDBSample /tmp/rocksdbjni
 	@rm -rf /tmp/rocksdbjni
 	@rm -rf /tmp/rocksdbjni_not_found
+
+test:
+	java -ea -Djava.library.path=.:../ -cp "$(ROCKSDB_JAR):.:./*" org.rocksdb.WriteBatchTest

java/RocksDBSample.java

@@ -93,6 +93,21 @@ public class RocksDBSample {
       assert(len == RocksDB.NOT_FOUND);
       len = db.get(testKey, enoughArray);
       assert(len == testValue.length);
+
+      db.remove(testKey);
+      len = db.get(testKey, enoughArray);
+      assert(len == RocksDB.NOT_FOUND);
+
+      // repeat the test with WriteOptions
+      WriteOptions writeOpts = new WriteOptions();
+      writeOpts.setSync(true);
+      writeOpts.setDisableWAL(true);
+      db.put(writeOpts, testKey, testValue);
+      len = db.get(testKey, enoughArray);
+      assert(len == testValue.length);
+      assert(new String(testValue).equals(
+          new String(enoughArray, 0, len)));
+      writeOpts.dispose();
     } catch (RocksDBException e) {
       System.err.println(e);
     }

java/org/rocksdb/RocksDB.java

@@ -1,4 +1,4 @@
-// Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+// Copyright (c) 2014, Facebook, Inc.  All rights reserved.
 // This source code is licensed under the BSD-style license found in the
 // LICENSE file in the root directory of this source tree. An additional grant
 // of patent rights can be found in the PATENTS file in the same directory.
@@ -64,6 +64,17 @@ public class RocksDB {
     put(key, key.length, value, value.length);
   }
 
+  /**
+   * Set the database entry for "key" to "value".
+   *
+   * @param key the specified key to be inserted.
+   * @param value the value associated with the specified key.
+   */
+  public void put(WriteOptions writeOpts, byte[] key, byte[] value)
+      throws RocksDBException {
+    put(writeOpts.nativeHandle_, key, key.length, value, value.length);
+  }
+
   /**
    * Get the value associated with the specified key.
    *
@@ -95,6 +106,25 @@ public class RocksDB {
     return get(key, key.length);
   }
 
+  /**
+   * Remove the database entry (if any) for "key".  Returns OK on
+   * success, and a non-OK status on error.  It is not an error if "key"
+   * did not exist in the database.
+   */
+  public void remove(byte[] key) throws RocksDBException {
+    remove(key, key.length);
+  }
+
+  /**
+   * Remove the database entry (if any) for "key".  Returns OK on
+   * success, and a non-OK status on error.  It is not an error if "key"
+   * did not exist in the database.
+   */
+  public void remove(WriteOptions writeOpt, byte[] key)
+      throws RocksDBException {
+    remove(writeOpt.nativeHandle_, key, key.length);
+  }
+
   @Override protected void finalize() {
     close();
   }
@@ -108,15 +138,23 @@ public class RocksDB {
 
   // native methods
   private native void open0(String path) throws RocksDBException;
-  private native void open(long optionsHandle, String path) throws RocksDBException;
+  private native void open(
+      long optionsHandle, String path) throws RocksDBException;
   private native void put(
       byte[] key, int keyLen,
       byte[] value, int valueLen) throws RocksDBException;
+  private native void put(
+      long writeOptHandle, byte[] key, int keyLen,
+      byte[] value, int valueLen) throws RocksDBException;
   private native int get(
       byte[] key, int keyLen,
       byte[] value, int valueLen) throws RocksDBException;
   private native byte[] get(
       byte[] key, int keyLen) throws RocksDBException;
+  private native void remove(
+      byte[] key, int keyLen) throws RocksDBException;
+  private native void remove(
+      long writeOptHandle, byte[] key, int keyLen) throws RocksDBException;
   private native void close0();
 
   private long nativeHandle_;

java/org/rocksdb/WriteBatch.java

@@ -0,0 +1,121 @@
+// Copyright (c) 2014, Facebook, Inc.  All rights reserved.
+// This source code is licensed under the BSD-style license found in the
+// LICENSE file in the root directory of this source tree. An additional grant
+// of patent rights can be found in the PATENTS file in the same directory.
+
+package org.rocksdb;
+
+import java.lang.*;
+import java.util.*;
+
+/**
+ * WriteBatch holds a collection of updates to apply atomically to a DB.
+ *
+ * The updates are applied in the order in which they are added
+ * to the WriteBatch.  For example, the value of "key" will be "v3"
+ * after the following batch is written:
+ *
+ *    batch.put("key", "v1");
+ *    batch.remove("key");
+ *    batch.put("key", "v2");
+ *    batch.put("key", "v3");
+ *
+ * Multiple threads can invoke const methods on a WriteBatch without
+ * external synchronization, but if any of the threads may call a
+ * non-const method, all threads accessing the same WriteBatch must use
+ * external synchronization.
+ */
+public class WriteBatch {
+  public WriteBatch() {
+    nativeHandle_ = 0;
+    newWriteBatch(0);
+  }
+
+  public WriteBatch(int reserved_bytes) {
+    nativeHandle_ = 0;
+    newWriteBatch(reserved_bytes);
+  }
+
+  /**
+   * Returns the number of updates in the batch.
+   */
+  public native int count();
+
+  /**
+   * Store the mapping "key->value" in the database.
+   */
+  public void put(byte[] key, byte[] value) {
+    put(key, key.length, value, value.length);
+  }
+
+  /**
+   * Merge "value" with the existing value of "key" in the database.
+   * "key->merge(existing, value)"
+   */
+  public void merge(byte[] key, byte[] value) {
+    merge(key, key.length, value, value.length);
+  }
+
+  /**
+   * If the database contains a mapping for "key", erase it.  Else do nothing.
+   */
+  public void remove(byte[] key) {
+    remove(key, key.length);
+  }
+
+  /**
+   * Append a blob of arbitrary size to the records in this batch. The blob will
+   * be stored in the transaction log but not in any other file. In particular,
+   * it will not be persisted to the SST files. When iterating over this
+   * WriteBatch, WriteBatch::Handler::LogData will be called with the contents
+   * of the blob as it is encountered. Blobs, puts, deletes, and merges will be
+   * encountered in the same order in thich they were inserted. The blob will
+   * NOT consume sequence number(s) and will NOT increase the count of the batch
+   *
+   * Example application: add timestamps to the transaction log for use in
+   * replication.
+   */
+  public void putLogData(byte[] blob) {
+    putLogData(blob, blob.length);
+  }
+
+  /**
+   * Clear all updates buffered in this batch
+   */
+  public native void clear();
+
+  /**
+   * Delete the c++ side pointer.
+   */
+  public synchronized void dispose() {
+    if (nativeHandle_ != 0) {
+      dispose0();
+    }
+  }
+
+  @Override protected void finalize() {
+    dispose();
+  }
+
+  private native void newWriteBatch(int reserved_bytes);
+  private native void put(byte[] key, int keyLen,
+                          byte[] value, int valueLen);
+  private native void merge(byte[] key, int keyLen,
+                            byte[] value, int valueLen);
+  private native void remove(byte[] key, int keyLen);
+  private native void putLogData(byte[] blob, int blobLen);
+  private native void dispose0();
+
+  private long nativeHandle_;
+}
+
+/**
+ * Package-private class which provides java api to access
+ * c++ WriteBatchInternal.
+ */
+class WriteBatchInternal {
+  static native void setSequence(WriteBatch batch, long sn);
+  static native long sequence(WriteBatch batch);
+  static native void append(WriteBatch b1, WriteBatch b2);
+}
+

java/org/rocksdb/WriteBatchTest.java

@@ -0,0 +1,125 @@
+//  Copyright (c) 2014, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+package org.rocksdb;
+
+import java.util.*;
+import java.lang.*;
+import java.io.UnsupportedEncodingException;
+
+/**
+ * This class mimics the db/write_batch_test.cc in the c++ rocksdb library.
+ */
+public class WriteBatchTest {
+  static {
+    System.loadLibrary("rocksdbjni");
+  }
+
+  public static void main(String args[]) {
+    System.out.println("Testing WriteBatchTest.Empty ===");
+    Empty();
+
+    System.out.println("Testing WriteBatchTest.Multiple ===");
+    Multiple();
+
+    System.out.println("Testing WriteBatchTest.Append ===");
+    Append();
+
+    System.out.println("Testing WriteBatchTest.Blob ===");
+    Blob();
+
+    // The following tests have not yet ported.
+    // Continue();
+    // PutGatherSlices();
+
+    System.out.println("Passed all WriteBatchTest!");
+  }
+
+  static void Empty() {
+    WriteBatch batch = new WriteBatch();
+    assert(batch.count() == 0);
+  }
+
+  static void Multiple() {
+    try {
+      WriteBatch batch =  new WriteBatch();
+      batch.put("foo".getBytes("US-ASCII"), "bar".getBytes("US-ASCII"));
+      batch.remove("box".getBytes("US-ASCII"));
+      batch.put("baz".getBytes("US-ASCII"), "boo".getBytes("US-ASCII"));
+      WriteBatchInternal.setSequence(batch, 100);
+      assert(100 == WriteBatchInternal.sequence(batch));
+      assert(3 == batch.count());
+      assert(new String("Put(baz, boo)@102" +
+                        "Delete(box)@101" +
+                        "Put(foo, bar)@100")
+                .equals(new String(getContents(batch), "US-ASCII")));
+    } catch (UnsupportedEncodingException e) {
+      System.err.println(e);
+      assert(false);
+    }
+  }
+
+  static void Append() {
+    WriteBatch b1 = new WriteBatch();
+    WriteBatch b2 = new WriteBatch();
+    WriteBatchInternal.setSequence(b1, 200);
+    WriteBatchInternal.setSequence(b2, 300);
+    WriteBatchInternal.append(b1, b2);
+    assert(getContents(b1).length == 0);
+    assert(b1.count() == 0);
+    try {
+      b2.put("a".getBytes("US-ASCII"), "va".getBytes("US-ASCII"));
+      WriteBatchInternal.append(b1, b2);
+      assert("Put(a, va)@200".equals(new String(getContents(b1), "US-ASCII")));
+      assert(1 == b1.count());
+      b2.clear();
+      b2.put("b".getBytes("US-ASCII"), "vb".getBytes("US-ASCII"));
+      WriteBatchInternal.append(b1, b2);
+      assert(new String("Put(a, va)@200" +
+                        "Put(b, vb)@201")
+                .equals(new String(getContents(b1), "US-ASCII")));
+      assert(2 == b1.count());
+      b2.remove("foo".getBytes("US-ASCII"));
+      WriteBatchInternal.append(b1, b2);
+      assert(new String("Put(a, va)@200" +
+                        "Put(b, vb)@202" +
+                        "Put(b, vb)@201" +
+                        "Delete(foo)@203")
+                 .equals(new String(getContents(b1), "US-ASCII")));
+      assert(4 == b1.count());
+    } catch (UnsupportedEncodingException e) {
+      System.err.println(e);
+      assert(false);
+    }
+  }
+
+  static void Blob() {
+    WriteBatch batch = new WriteBatch();
+    try {
+      batch.put("k1".getBytes("US-ASCII"), "v1".getBytes("US-ASCII"));
+      batch.put("k2".getBytes("US-ASCII"), "v2".getBytes("US-ASCII"));
+      batch.put("k3".getBytes("US-ASCII"), "v3".getBytes("US-ASCII"));
+      batch.putLogData("blob1".getBytes("US-ASCII"));
+      batch.remove("k2".getBytes("US-ASCII"));
+      batch.putLogData("blob2".getBytes("US-ASCII"));
+      batch.merge("foo".getBytes("US-ASCII"), "bar".getBytes("US-ASCII"));
+      assert(5 == batch.count());
+      assert(new String("Merge(foo, bar)@4" +
+                        "Put(k1, v1)@0" +
+                        "Delete(k2)@3" +
+                        "Put(k2, v2)@1" +
+                        "Put(k3, v3)@2")
+                .equals(new String(getContents(batch), "US-ASCII")));
+    } catch (UnsupportedEncodingException e) {
+      System.err.println(e);
+      assert(false);
+    }
+  }
+
+  static native byte[] getContents(WriteBatch batch);
+}

java/org/rocksdb/WriteOptions.java

@@ -0,0 +1,96 @@
+// Copyright (c) 2014, Facebook, Inc.  All rights reserved.
+// This source code is licensed under the BSD-style license found in the
+// LICENSE file in the root directory of this source tree. An additional grant
+// of patent rights can be found in the PATENTS file in the same directory.
+
+package org.rocksdb;
+
+/**
+ * Options that control write operations.
+ *
+ * Note that developers should call WriteOptions.dispose() to release the
+ * c++ side memory before a WriteOptions instance runs out of scope.
+ */
+public class WriteOptions {
+  public WriteOptions() {
+    nativeHandle_ = 0;
+    newWriteOptions();
+  }
+
+  public synchronized void dispose() {
+    if (nativeHandle_ != 0) {
+      dispose0(nativeHandle_);
+    }
+  }
+
+  /**
+   * If true, the write will be flushed from the operating system
+   * buffer cache (by calling WritableFile::Sync()) before the write
+   * is considered complete.  If this flag is true, writes will be
+   * slower.
+   *
+   * If this flag is false, and the machine crashes, some recent
+   * writes may be lost.  Note that if it is just the process that
+   * crashes (i.e., the machine does not reboot), no writes will be
+   * lost even if sync==false.
+   *
+   * In other words, a DB write with sync==false has similar
+   * crash semantics as the "write()" system call.  A DB write
+   * with sync==true has similar crash semantics to a "write()"
+   * system call followed by "fdatasync()".
+   *
+   * Default: false
+   */
+  public void setSync(boolean flag) {
+    setSync(nativeHandle_, flag);
+  }
+
+  /**
+   * If true, the write will be flushed from the operating system
+   * buffer cache (by calling WritableFile::Sync()) before the write
+   * is considered complete.  If this flag is true, writes will be
+   * slower.
+   *
+   * If this flag is false, and the machine crashes, some recent
+   * writes may be lost.  Note that if it is just the process that
+   * crashes (i.e., the machine does not reboot), no writes will be
+   * lost even if sync==false.
+   *
+   * In other words, a DB write with sync==false has similar
+   * crash semantics as the "write()" system call.  A DB write
+   * with sync==true has similar crash semantics to a "write()"
+   * system call followed by "fdatasync()".
+   */
+  public boolean sync() {
+    return sync(nativeHandle_);
+  }
+
+  /**
+   * If true, writes will not first go to the write ahead log,
+   * and the write may got lost after a crash.
+   */
+  public void setDisableWAL(boolean flag) {
+    setDisableWAL(nativeHandle_, flag);
+  }
+
+  /**
+   * If true, writes will not first go to the write ahead log,
+   * and the write may got lost after a crash.
+   */
+  public boolean disableWAL() {
+    return disableWAL(nativeHandle_);
+  }
+
+  @Override protected void finalize() {
+    dispose();
+  }
+
+  private native void newWriteOptions();
+  private native void setSync(long handle, boolean flag);
+  private native boolean sync(long handle);
+  private native void setDisableWAL(long handle, boolean flag);
+  private native boolean disableWAL(long handle);
+  private native void dispose0(long handle);
+
+  protected  long nativeHandle_;
+}

java/rocksjni/options.cc

@@ -11,8 +11,10 @@
 #include <string>
 
 #include "include/org_rocksdb_Options.h"
+#include "include/org_rocksdb_WriteOptions.h"
 #include "rocksjni/portal.h"
 #include "rocksdb/db.h"
+#include "rocksdb/options.h"
 
 /*
  * Class:     org_rocksdb_Options
@@ -55,3 +57,72 @@ jboolean Java_org_rocksdb_Options_createIfMissing(
     JNIEnv* env, jobject jobj, jlong jhandle) {
   return reinterpret_cast<rocksdb::Options*>(jhandle)->create_if_missing;
 }
+
+//////////////////////////////////////////////////////////////////////////////
+// WriteOptions
+
+/*
+ * Class:     org_rocksdb_WriteOptions
+ * Method:    newWriteOptions
+ * Signature: ()V
+ */
+void Java_org_rocksdb_WriteOptions_newWriteOptions(
+    JNIEnv* env, jobject jwrite_options) {
+  rocksdb::WriteOptions* op = new rocksdb::WriteOptions();
+  rocksdb::WriteOptionsJni::setHandle(env, jwrite_options, op);
+}
+
+/*
+ * Class:     org_rocksdb_WriteOptions
+ * Method:    dispose0
+ * Signature: ()V
+ */
+void Java_org_rocksdb_WriteOptions_dispose0(
+    JNIEnv* env, jobject jwrite_options, jlong jhandle) {
+  auto write_options = reinterpret_cast<rocksdb::WriteOptions*>(jhandle);
+  delete write_options;
+
+  rocksdb::WriteOptionsJni::setHandle(env, jwrite_options, nullptr);
+}
+
+/*
+ * Class:     org_rocksdb_WriteOptions
+ * Method:    setSync
+ * Signature: (JZ)V
+ */
+void Java_org_rocksdb_WriteOptions_setSync(
+  JNIEnv* env, jobject jwrite_options, jlong jhandle, jboolean jflag) {
+  reinterpret_cast<rocksdb::WriteOptions*>(jhandle)->sync = jflag;
+}
+
+/*
+ * Class:     org_rocksdb_WriteOptions
+ * Method:    sync
+ * Signature: (J)Z
+ */
+jboolean Java_org_rocksdb_WriteOptions_sync(
+    JNIEnv* env, jobject jwrite_options, jlong jhandle) {
+  return reinterpret_cast<rocksdb::WriteOptions*>(jhandle)->sync;
+}
+
+/*
+ * Class:     org_rocksdb_WriteOptions
+ * Method:    setDisableWAL
+ * Signature: (JZ)V
+ */
+void Java_org_rocksdb_WriteOptions_setDisableWAL(
+    JNIEnv* env, jobject jwrite_options, jlong jhandle, jboolean jflag) {
+  reinterpret_cast<rocksdb::WriteOptions*>(jhandle)->disableWAL = jflag;
+}
+
+/*
+ * Class:     org_rocksdb_WriteOptions
+ * Method:    disableWAL
+ * Signature: (J)Z
+ */
+jboolean Java_org_rocksdb_WriteOptions_disableWAL(
+    JNIEnv* env, jobject jwrite_options, jlong jhandle) {
+  return reinterpret_cast<rocksdb::WriteOptions*>(jhandle)->disableWAL;
+}
+
+

java/rocksjni/portal.h

@@ -109,5 +109,66 @@ class OptionsJni {
   }
 };
 
+class WriteOptionsJni {
+ public:
+  // Get the java class id of org.rocksdb.WriteOptions.
+  static jclass getJClass(JNIEnv* env) {
+    static jclass jclazz = env->FindClass("org/rocksdb/WriteOptions");
+    assert(jclazz != nullptr);
+    return jclazz;
+  }
+
+  // Get the field id of the member variable of org.rocksdb.WriteOptions
+  // that stores the pointer to rocksdb::WriteOptions
+  static jfieldID getHandleFieldID(JNIEnv* env) {
+    static jfieldID fid = env->GetFieldID(
+        getJClass(env), "nativeHandle_", "J");
+    assert(fid != nullptr);
+    return fid;
+  }
+
+  // Get the pointer to rocksdb::WriteOptions
+  static rocksdb::WriteOptions* getHandle(JNIEnv* env, jobject jobj) {
+    return reinterpret_cast<rocksdb::WriteOptions*>(
+        env->GetLongField(jobj, getHandleFieldID(env)));
+  }
+
+  // Pass the rocksdb::WriteOptions pointer to the java side.
+  static void setHandle(JNIEnv* env, jobject jobj, rocksdb::WriteOptions* op) {
+    env->SetLongField(
+        jobj, getHandleFieldID(env),
+        reinterpret_cast<jlong>(op));
+  }
+};
+
+class WriteBatchJni {
+ public:
+  static jclass getJClass(JNIEnv* env) {
+    static jclass jclazz = env->FindClass("org/rocksdb/WriteBatch");
+    assert(jclazz != nullptr);
+    return jclazz;
+  }
+
+  static jfieldID getHandleFieldID(JNIEnv* env) {
+    static jfieldID fid = env->GetFieldID(
+        getJClass(env), "nativeHandle_", "J");
+    assert(fid != nullptr);
+    return fid;
+  }
+
+  // Get the pointer to rocksdb::WriteBatch of the specified
+  // org.rocksdb.WriteBatch.
+  static rocksdb::WriteBatch* getHandle(JNIEnv* env, jobject jwb) {
+    return reinterpret_cast<rocksdb::WriteBatch*>(
+        env->GetLongField(jwb, getHandleFieldID(env)));
+  }
+
+  // Pass the rocksdb::WriteBatch pointer to the java side.
+  static void setHandle(JNIEnv* env, jobject jwb, rocksdb::WriteBatch* wb) {
+    env->SetLongField(
+        jwb, getHandleFieldID(env),
+        reinterpret_cast<jlong>(wb));
+  }
+};
 }  // namespace rocksdb
 #endif  // JAVA_ROCKSJNI_PORTAL_H_

java/rocksjni/rocksjni.cc

@@ -15,6 +15,9 @@
 #include "rocksjni/portal.h"
 #include "rocksdb/db.h"
 
+//////////////////////////////////////////////////////////////////////////////
+// rocksdb::DB::Open
+
 void rocksdb_open_helper(
   JNIEnv* env, jobject java_db, jstring jdb_path, const rocksdb::Options& opt) {
   rocksdb::DB* db;
@@ -54,27 +57,20 @@ void Java_org_rocksdb_RocksDB_open(
   rocksdb_open_helper(env, jdb, jdb_path, *options);
 }
 
-/*
+//////////////////////////////////////////////////////////////////////////////
- * Class:     org_rocksdb_RocksDB
+// rocksdb::DB::Put
- * Method:    put
+
- * Signature: ([BI[BI)V
+void rocksdb_put_helper(
- */
+    JNIEnv* env, rocksdb::DB* db, const rocksdb::WriteOptions& write_options,
-void Java_org_rocksdb_RocksDB_put(
-    JNIEnv* env, jobject jdb,
     jbyteArray jkey, jint jkey_len,
     jbyteArray jvalue, jint jvalue_len) {
-  rocksdb::DB* db = rocksdb::RocksDBJni::getHandle(env, jdb);
 
-  jboolean isCopy;
+  jbyte* key = env->GetByteArrayElements(jkey, 0);
-  jbyte* key = env->GetByteArrayElements(jkey, &isCopy);
+  jbyte* value = env->GetByteArrayElements(jvalue, 0);
-  jbyte* value = env->GetByteArrayElements(jvalue, &isCopy);
+  rocksdb::Slice key_slice(reinterpret_cast<char*>(key), jkey_len);
-  rocksdb::Slice key_slice(
+  rocksdb::Slice value_slice(reinterpret_cast<char*>(value), jvalue_len);
-      reinterpret_cast<char*>(key), jkey_len);
-  rocksdb::Slice value_slice(
-      reinterpret_cast<char*>(value), jvalue_len);
 
-  rocksdb::Status s = db->Put(
+  rocksdb::Status s = db->Put(write_options, key_slice, value_slice);
-      rocksdb::WriteOptions(), key_slice, value_slice);
 
   // trigger java unref on key and value.
   // by passing JNI_ABORT, it will simply release the reference without
@@ -88,6 +84,45 @@ void Java_org_rocksdb_RocksDB_put(
   rocksdb::RocksDBExceptionJni::ThrowNew(env, s);
 }
 
+/*
+ * Class:     org_rocksdb_RocksDB
+ * Method:    put
+ * Signature: ([BI[BI)V
+ */
+void Java_org_rocksdb_RocksDB_put___3BI_3BI(
+    JNIEnv* env, jobject jdb,
+    jbyteArray jkey, jint jkey_len,
+    jbyteArray jvalue, jint jvalue_len) {
+  rocksdb::DB* db = rocksdb::RocksDBJni::getHandle(env, jdb);
+  static const rocksdb::WriteOptions default_write_options =
+      rocksdb::WriteOptions();
+
+  rocksdb_put_helper(env, db, default_write_options,
+                     jkey, jkey_len,
+                     jvalue, jvalue_len);
+}
+
+/*
+ * Class:     org_rocksdb_RocksDB
+ * Method:    put
+ * Signature: (J[BI[BI)V
+ */
+void Java_org_rocksdb_RocksDB_put__J_3BI_3BI(
+    JNIEnv* env, jobject jdb, jlong jwrite_options_handle,
+    jbyteArray jkey, jint jkey_len,
+    jbyteArray jvalue, jint jvalue_len) {
+  rocksdb::DB* db = rocksdb::RocksDBJni::getHandle(env, jdb);
+  auto write_options = reinterpret_cast<rocksdb::WriteOptions*>(
+      jwrite_options_handle);
+
+  rocksdb_put_helper(env, db, *write_options,
+                     jkey, jkey_len,
+                     jvalue, jvalue_len);
+}
+
+//////////////////////////////////////////////////////////////////////////////
+// rocksdb::DB::Get
+
 /*
  * Class:     org_rocksdb_RocksDB
  * Method:    get
@@ -184,6 +219,59 @@ jint Java_org_rocksdb_RocksDB_get___3BI_3BI(
   return static_cast<jint>(cvalue_len);
 }
 
+//////////////////////////////////////////////////////////////////////////////
+// rocksdb::DB::Delete()
+void rocksdb_remove_helper(
+    JNIEnv* env, rocksdb::DB* db, const rocksdb::WriteOptions& write_options,
+    jbyteArray jkey, jint jkey_len) {
+  jbyte* key = env->GetByteArrayElements(jkey, 0);
+  rocksdb::Slice key_slice(reinterpret_cast<char*>(key), jkey_len);
+
+  rocksdb::Status s = db->Delete(write_options, key_slice);
+
+  // trigger java unref on key and value.
+  // by passing JNI_ABORT, it will simply release the reference without
+  // copying the result back to the java byte array.
+  env->ReleaseByteArrayElements(jkey, key, JNI_ABORT);
+
+  if (!s.ok()) {
+    rocksdb::RocksDBExceptionJni::ThrowNew(env, s);
+  }
+  return;
+}
+
+
+/*
+ * Class:     org_rocksdb_RocksDB
+ * Method:    remove
+ * Signature: ([BI)V
+ */
+void Java_org_rocksdb_RocksDB_remove___3BI(
+    JNIEnv* env, jobject jdb, jbyteArray jkey, jint jkey_len) {
+  rocksdb::DB* db = rocksdb::RocksDBJni::getHandle(env, jdb);
+  static const rocksdb::WriteOptions default_write_options =
+      rocksdb::WriteOptions();
+
+  rocksdb_remove_helper(env, db, default_write_options, jkey, jkey_len);
+}
+
+/*
+ * Class:     org_rocksdb_RocksDB
+ * Method:    remove
+ * Signature: (J[BI)V
+ */
+void Java_org_rocksdb_RocksDB_remove__J_3BI(
+    JNIEnv* env, jobject jdb, jlong jwrite_options,
+    jbyteArray jkey, jint jkey_len) {
+  rocksdb::DB* db = rocksdb::RocksDBJni::getHandle(env, jdb);
+  auto write_options = reinterpret_cast<rocksdb::WriteOptions*>(jwrite_options);
+
+  rocksdb_remove_helper(env, db, *write_options, jkey, jkey_len);
+}
+
+//////////////////////////////////////////////////////////////////////////////
+// rocksdb::DB::~DB()
+
 /*
  * Class:     org_rocksdb_RocksDB
  * Method:    close0
@@ -192,8 +280,8 @@ jint Java_org_rocksdb_RocksDB_get___3BI_3BI(
 void Java_org_rocksdb_RocksDB_close0(
     JNIEnv* env, jobject java_db) {
   rocksdb::DB* db = rocksdb::RocksDBJni::getHandle(env, java_db);
+  assert(db != nullptr);
   delete db;
-  db = nullptr;
 
-  rocksdb::RocksDBJni::setHandle(env, java_db, db);
+  rocksdb::RocksDBJni::setHandle(env, java_db, nullptr);
 }

java/rocksjni/write_batch.cc

@@ -0,0 +1,263 @@
+// Copyright (c) 2014, Facebook, Inc.  All rights reserved.
+// This source code is licensed under the BSD-style license found in the
+// LICENSE file in the root directory of this source tree. An additional grant
+// of patent rights can be found in the PATENTS file in the same directory.
+//
+// This file implements the "bridge" between Java and C++ and enables
+// calling c++ rocksdb::WriteBatch methods from Java side.
+#include <memory>
+
+#include "include/org_rocksdb_WriteBatch.h"
+#include "include/org_rocksdb_WriteBatchInternal.h"
+#include "include/org_rocksdb_WriteBatchTest.h"
+#include "rocksjni/portal.h"
+#include "rocksdb/db.h"
+#include "db/memtable.h"
+#include "rocksdb/write_batch.h"
+#include "db/write_batch_internal.h"
+#include "rocksdb/env.h"
+#include "rocksdb/memtablerep.h"
+#include "util/logging.h"
+#include "util/testharness.h"
+
+/*
+ * Class:     org_rocksdb_WriteBatch
+ * Method:    newWriteBatch
+ * Signature: (I)V
+ */
+void Java_org_rocksdb_WriteBatch_newWriteBatch(
+    JNIEnv* env, jobject jobj, jint jreserved_bytes) {
+  rocksdb::WriteBatch* wb = new rocksdb::WriteBatch(
+      static_cast<size_t>(jreserved_bytes));
+
+  rocksdb::WriteBatchJni::setHandle(env, jobj, wb);
+}
+
+/*
+ * Class:     org_rocksdb_WriteBatch
+ * Method:    count
+ * Signature: ()I
+ */
+jint Java_org_rocksdb_WriteBatch_count(JNIEnv* env, jobject jobj) {
+  rocksdb::WriteBatch* wb = rocksdb::WriteBatchJni::getHandle(env, jobj);
+  assert(wb != nullptr);
+
+  return static_cast<jint>(wb->Count());
+}
+
+/*
+ * Class:     org_rocksdb_WriteBatch
+ * Method:    clear
+ * Signature: ()V
+ */
+void Java_org_rocksdb_WriteBatch_clear(JNIEnv* env, jobject jobj) {
+  rocksdb::WriteBatch* wb = rocksdb::WriteBatchJni::getHandle(env, jobj);
+  assert(wb != nullptr);
+
+  wb->Clear();
+}
+
+/*
+ * Class:     org_rocksdb_WriteBatch
+ * Method:    put
+ * Signature: ([BI[BI)V
+ */
+void Java_org_rocksdb_WriteBatch_put(
+    JNIEnv* env, jobject jobj,
+    jbyteArray jkey, jint jkey_len,
+    jbyteArray jvalue, jint jvalue_len) {
+  rocksdb::WriteBatch* wb = rocksdb::WriteBatchJni::getHandle(env, jobj);
+  assert(wb != nullptr);
+
+  jbyte* key = env->GetByteArrayElements(jkey, nullptr);
+  jbyte* value = env->GetByteArrayElements(jvalue, nullptr);
+  rocksdb::Slice key_slice(reinterpret_cast<char*>(key), jkey_len);
+  rocksdb::Slice value_slice(reinterpret_cast<char*>(value), jvalue_len);
+  wb->Put(key_slice, value_slice);
+  env->ReleaseByteArrayElements(jkey, key, JNI_ABORT);
+  env->ReleaseByteArrayElements(jvalue, value, JNI_ABORT);
+}
+
+/*
+ * Class:     org_rocksdb_WriteBatch
+ * Method:    merge
+ * Signature: ([BI[BI)V
+ */
+JNIEXPORT void JNICALL Java_org_rocksdb_WriteBatch_merge(
+    JNIEnv* env, jobject jobj,
+    jbyteArray jkey, jint jkey_len,
+    jbyteArray jvalue, jint jvalue_len) {
+  rocksdb::WriteBatch* wb = rocksdb::WriteBatchJni::getHandle(env, jobj);
+  assert(wb != nullptr);
+
+  jbyte* key = env->GetByteArrayElements(jkey, nullptr);
+  jbyte* value = env->GetByteArrayElements(jvalue, nullptr);
+  rocksdb::Slice key_slice(reinterpret_cast<char*>(key), jkey_len);
+  rocksdb::Slice value_slice(reinterpret_cast<char*>(value), jvalue_len);
+  wb->Merge(key_slice, value_slice);
+  env->ReleaseByteArrayElements(jkey, key, JNI_ABORT);
+  env->ReleaseByteArrayElements(jvalue, value, JNI_ABORT);
+}
+
+/*
+ * Class:     org_rocksdb_WriteBatch
+ * Method:    remove
+ * Signature: ([BI)V
+ */
+JNIEXPORT void JNICALL Java_org_rocksdb_WriteBatch_remove(
+    JNIEnv* env, jobject jobj,
+    jbyteArray jkey, jint jkey_len) {
+  rocksdb::WriteBatch* wb = rocksdb::WriteBatchJni::getHandle(env, jobj);
+  assert(wb != nullptr);
+
+  jbyte* key = env->GetByteArrayElements(jkey, nullptr);
+  rocksdb::Slice key_slice(reinterpret_cast<char*>(key), jkey_len);
+  wb->Delete(key_slice);
+  env->ReleaseByteArrayElements(jkey, key, JNI_ABORT);
+}
+
+/*
+ * Class:     org_rocksdb_WriteBatch
+ * Method:    putLogData
+ * Signature: ([BI)V
+ */
+void Java_org_rocksdb_WriteBatch_putLogData(
+    JNIEnv* env, jobject jobj, jbyteArray jblob, jint jblob_len) {
+  rocksdb::WriteBatch* wb = rocksdb::WriteBatchJni::getHandle(env, jobj);
+  assert(wb != nullptr);
+
+  jbyte* blob = env->GetByteArrayElements(jblob, nullptr);
+  rocksdb::Slice blob_slice(reinterpret_cast<char*>(blob), jblob_len);
+  wb->PutLogData(blob_slice);
+  env->ReleaseByteArrayElements(jblob, blob, JNI_ABORT);
+}
+
+/*
+ * Class:     org_rocksdb_WriteBatch
+ * Method:    dispose0
+ * Signature: ()V
+ */
+void Java_org_rocksdb_WriteBatch_dispose0(JNIEnv* env, jobject jobj) {
+  rocksdb::WriteBatch* wb = rocksdb::WriteBatchJni::getHandle(env, jobj);
+  assert(wb != nullptr);
+  delete wb;
+
+  rocksdb::WriteBatchJni::setHandle(env, jobj, nullptr);
+}
+
+/*
+ * Class:     org_rocksdb_WriteBatchInternal
+ * Method:    setSequence
+ * Signature: (Lorg/rocksdb/WriteBatch;J)V
+ */
+void Java_org_rocksdb_WriteBatchInternal_setSequence(
+    JNIEnv* env, jclass jclazz, jobject jobj, jlong jsn) {
+  rocksdb::WriteBatch* wb = rocksdb::WriteBatchJni::getHandle(env, jobj);
+  assert(wb != nullptr);
+
+  rocksdb::WriteBatchInternal::SetSequence(
+      wb, static_cast<rocksdb::SequenceNumber>(jsn));
+}
+
+/*
+ * Class:     org_rocksdb_WriteBatchInternal
+ * Method:    sequence
+ * Signature: (Lorg/rocksdb/WriteBatch;)J
+ */
+jlong Java_org_rocksdb_WriteBatchInternal_sequence(
+    JNIEnv* env, jclass jclazz, jobject jobj) {
+  rocksdb::WriteBatch* wb = rocksdb::WriteBatchJni::getHandle(env, jobj);
+  assert(wb != nullptr);
+
+  return static_cast<jlong>(rocksdb::WriteBatchInternal::Sequence(wb));
+}
+
+/*
+ * Class:     org_rocksdb_WriteBatchInternal
+ * Method:    append
+ * Signature: (Lorg/rocksdb/WriteBatch;Lorg/rocksdb/WriteBatch;)V
+ */
+void Java_org_rocksdb_WriteBatchInternal_append(
+    JNIEnv* env, jclass jclazz, jobject jwb1, jobject jwb2) {
+  rocksdb::WriteBatch* wb1 = rocksdb::WriteBatchJni::getHandle(env, jwb1);
+  assert(wb1 != nullptr);
+  rocksdb::WriteBatch* wb2 = rocksdb::WriteBatchJni::getHandle(env, jwb2);
+  assert(wb2 != nullptr);
+
+  rocksdb::WriteBatchInternal::Append(wb1, wb2);
+}
+
+/*
+ * Class:     org_rocksdb_WriteBatchTest
+ * Method:    getContents
+ * Signature: (Lorg/rocksdb/WriteBatch;)[B
+ */
+jbyteArray Java_org_rocksdb_WriteBatchTest_getContents(
+    JNIEnv* env, jclass jclazz, jobject jobj) {
+  rocksdb::WriteBatch* b = rocksdb::WriteBatchJni::getHandle(env, jobj);
+  assert(b != nullptr);
+
+  // todo: Currently the following code is directly copied from
+  // db/write_bench_test.cc.  It could be implemented in java once
+  // all the necessary components can be accessed via jni api.
+
+  rocksdb::InternalKeyComparator cmp(rocksdb::BytewiseComparator());
+  auto factory = std::make_shared<rocksdb::SkipListFactory>();
+  rocksdb::Options options;
+  options.memtable_factory = factory;
+  rocksdb::MemTable* mem = new rocksdb::MemTable(cmp, options);
+  mem->Ref();
+  std::string state;
+  rocksdb::Status s = rocksdb::WriteBatchInternal::InsertInto(b, mem, &options);
+  int count = 0;
+  rocksdb::Iterator* iter = mem->NewIterator();
+  for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
+    rocksdb::ParsedInternalKey ikey;
+    memset(reinterpret_cast<void*>(&ikey), 0, sizeof(ikey));
+    ASSERT_TRUE(rocksdb::ParseInternalKey(iter->key(), &ikey));
+    switch (ikey.type) {
+      case rocksdb::kTypeValue:
+        state.append("Put(");
+        state.append(ikey.user_key.ToString());
+        state.append(", ");
+        state.append(iter->value().ToString());
+        state.append(")");
+        count++;
+        break;
+      case rocksdb::kTypeMerge:
+        state.append("Merge(");
+        state.append(ikey.user_key.ToString());
+        state.append(", ");
+        state.append(iter->value().ToString());
+        state.append(")");
+        count++;
+        break;
+      case rocksdb::kTypeDeletion:
+        state.append("Delete(");
+        state.append(ikey.user_key.ToString());
+        state.append(")");
+        count++;
+        break;
+      default:
+        assert(false);
+        break;
+    }
+    state.append("@");
+    state.append(rocksdb::NumberToString(ikey.sequence));
+  }
+  delete iter;
+  if (!s.ok()) {
+    state.append(s.ToString());
+  } else if (count != rocksdb::WriteBatchInternal::Count(b)) {
+    state.append("CountMismatch()");
+  }
+  delete mem->Unref();
+
+  jbyteArray jstate = env->NewByteArray(state.size());
+  env->SetByteArrayRegion(
+      jstate, 0, state.size(),
+      reinterpret_cast<const jbyte*>(state.c_str()));
+
+  return jstate;
+}
+