Merge pull request #377 from fyrz/RocksJava-KeyMayExist

[RocksJava] KeyMayExist w/o ColumnFamilies

java/org/rocksdb/RocksDB.java

@@ -419,6 +419,22 @@ public class RocksDB extends RocksObject {
         columnFamilyHandle.nativeHandle_);
   }
 
+  /**
+   * If the key definitely does not exist in the database, then this method
+   * returns false, else true.
+   *
+   * This check is potentially lighter-weight than invoking DB::Get(). One way
+   * to make this lighter weight is to avoid doing any IOs.
+   *
+   * @param key byte array of a key to search for
+   * @param value StringBuffer instance which is a out parameter if a value is
+   *    found in block-cache.
+   * @return boolean value indicating if key does not exist or might exist.
+   */
+  public boolean keyMayExist(byte[] key, StringBuffer value){
+    return keyMayExist(key, key.length, value);
+  }
+
   /**
    * If the key definitely does not exist in the database, then this method
    * returns false, else true.
@@ -438,6 +454,26 @@ public class RocksDB extends RocksObject {
         value);
   }
 
+  /**
+   * If the key definitely does not exist in the database, then this method
+   * returns false, else true.
+   *
+   * This check is potentially lighter-weight than invoking DB::Get(). One way
+   * to make this lighter weight is to avoid doing any IOs.
+   *
+   * @param readOptions {@link ReadOptions} instance
+   * @param columnFamilyHandle {@link ColumnFamilyHandle} instance
+   * @param key byte array of a key to search for
+   * @param value StringBuffer instance which is a out parameter if a value is
+   *    found in block-cache.
+   * @return boolean value indicating if key does not exist or might exist.
+   */
+  public boolean keyMayExist(ReadOptions readOptions,
+      byte[] key, StringBuffer value){
+    return keyMayExist(readOptions.nativeHandle_,
+        key, key.length, value);
+  }
+
   /**
    * If the key definitely does not exist in the database, then this method
    * returns false, else true.
@@ -1086,8 +1122,12 @@ public class RocksDB extends RocksObject {
       byte[] value, int valueLen, long cfHandle) throws RocksDBException;
   protected native void write(
       long writeOptHandle, long batchHandle) throws RocksDBException;
+  protected native boolean keyMayExist(byte[] key, int keyLen,
+      StringBuffer stringBuffer);
   protected native boolean keyMayExist(byte[] key, int keyLen,
       long cfHandle, StringBuffer stringBuffer);
+  protected native boolean keyMayExist(long optionsHandle, byte[] key, int keyLen,
+      StringBuffer stringBuffer);
   protected native boolean keyMayExist(long optionsHandle, byte[] key, int keyLen,
       long cfHandle, StringBuffer stringBuffer);
   protected native void merge(

java/org/rocksdb/test/KeyMayExistTest.java

@@ -4,10 +4,7 @@
 // of patent rights can be found in the PATENTS file in the same directory.
 package org.rocksdb.test;
 
-import org.rocksdb.ColumnFamilyHandle;
-import org.rocksdb.Options;
-import org.rocksdb.RocksDB;
-import org.rocksdb.RocksDBException;
+import org.rocksdb.*;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -34,13 +31,39 @@ public class KeyMayExistTest {
       assert(columnFamilyHandleList.size()==2);
 
       db.put("key".getBytes(), "value".getBytes());
+      // Test without column family
       StringBuffer retValue = new StringBuffer();
+      if (db.keyMayExist("key".getBytes(), retValue)) {
+        assert(retValue.toString().equals("value"));
+      } else {
+        assert(false);
+      }
+      // Test without column family but with readOptions
+      retValue = new StringBuffer();
+      if (db.keyMayExist(new ReadOptions(), "key".getBytes(),
+          retValue)) {
+        assert(retValue.toString().equals("value"));
+      } else {
+        assert(false);
+      }
+      // Test with column family
+      retValue = new StringBuffer();
       if (db.keyMayExist(columnFamilyHandleList.get(0), "key".getBytes(),
           retValue)) {
         assert(retValue.toString().equals("value"));
       } else {
         assert(false);
       }
+      // Test with column family and readOptions
+      retValue = new StringBuffer();
+      if (db.keyMayExist(new ReadOptions(),
+          columnFamilyHandleList.get(0), "key".getBytes(),
+          retValue)) {
+        assert(retValue.toString().equals("value"));
+      } else {
+        assert(false);
+      }
+      // KeyMayExist in CF1 must return false
       assert(db.keyMayExist(columnFamilyHandleList.get(1), "key".getBytes(),
           retValue) == false);
       System.out.println("Passed KeyMayExistTest");

java/rocksjni/rocksjni.cc

@@ -390,8 +390,15 @@ jboolean key_may_exist_helper(JNIEnv* env, rocksdb::DB* db,
   jboolean isCopy;
   jbyte* key = env->GetByteArrayElements(jkey, &isCopy);
   rocksdb::Slice key_slice(reinterpret_cast<char*>(key), jkey_len);
-  bool keyMaxExist = db->KeyMayExist(read_opt, cf_handle, key_slice,
+  bool keyMayExist;
+  if (cf_handle != nullptr) {
+    keyMayExist = db->KeyMayExist(read_opt, cf_handle, key_slice,
+        &value, &value_found);
+  } else {
+    keyMayExist = db->KeyMayExist(read_opt, key_slice,
         &value, &value_found);
+  }
+
   if (value_found && !value.empty()) {
     jclass clazz = env->GetObjectClass(jvalue);
     jmethodID mid = env->GetMethodID(clazz, "append",
@@ -400,7 +407,20 @@ jboolean key_may_exist_helper(JNIEnv* env, rocksdb::DB* db,
     env->CallObjectMethod(jvalue, mid, new_value_str);
   }
   env->ReleaseByteArrayElements(jkey, key, JNI_ABORT);
-  return static_cast<jboolean>(keyMaxExist);
+  return static_cast<jboolean>(keyMayExist);
+}
+
+/*
+ * Class:     org_rocksdb_RocksDB
+ * Method:    keyMayExist
+ * Signature: ([BILjava/lang/StringBuffer;)Z
+ */
+jboolean Java_org_rocksdb_RocksDB_keyMayExist___3BILjava_lang_StringBuffer_2(
+    JNIEnv* env, jobject jdb, jbyteArray jkey, jint jkey_len,
+    jobject jvalue) {
+  rocksdb::DB* db = rocksdb::RocksDBJni::getHandle(env, jdb);
+  return key_may_exist_helper(env, db, rocksdb::ReadOptions(),
+      nullptr, jkey, jkey_len, jvalue);
 }
 
 /*
@@ -424,6 +444,21 @@ jboolean Java_org_rocksdb_RocksDB_keyMayExist___3BIJLjava_lang_StringBuffer_2(
   return true;
 }
 
+/*
+ * Class:     org_rocksdb_RocksDB
+ * Method:    keyMayExist
+ * Signature: (J[BILjava/lang/StringBuffer;)Z
+ */
+jboolean Java_org_rocksdb_RocksDB_keyMayExist__J_3BILjava_lang_StringBuffer_2(
+    JNIEnv* env, jobject jdb, jlong jread_options_handle,
+    jbyteArray jkey, jint jkey_len, jobject jvalue) {
+  rocksdb::DB* db = rocksdb::RocksDBJni::getHandle(env, jdb);
+  auto& read_options = *reinterpret_cast<rocksdb::ReadOptions*>(
+      jread_options_handle);
+  return key_may_exist_helper(env, db, read_options,
+      nullptr, jkey, jkey_len, jvalue);
+}
+
 /*
  * Class:     org_rocksdb_RocksDB
  * Method:    keyMayExist