Add more iterator functions

java/RocksDBSample.java

@@ -145,6 +145,9 @@ public class RocksDBSample {
       Iterator iterator = db.iterator();
       iterator.seekToFirst();
       assert(iterator.isValid());
+      iterator.next();
+      iterator.seekToLast();
+      iterator.prev();
       iterator.close();      
     } catch (RocksDBException e) {
       System.err.println(e);

java/org/rocksdb/Iterator.java

@@ -22,6 +22,21 @@ public class Iterator {
     seekToFirst0(nativeHandle_);
   }
   
+  public void seekToLast() {
+    assert(isInitialized());
+    seekToLast0(nativeHandle_);
+  }
+  
+  public void next() {
+    assert(isInitialized());
+    next0(nativeHandle_);
+  }
+  
+  public void prev() {
+    assert(isInitialized());
+    prev0(nativeHandle_);
+  }
+  
   public synchronized void close() {
     if(nativeHandle_ != 0) {
       close0(nativeHandle_);
@@ -39,4 +54,7 @@ public class Iterator {
   private native boolean isValid0(long handle);
   private native void close0(long handle);
   private native void seekToFirst0(long handle);
+  private native void seekToLast0(long handle);
+  private native void next0(long handle);
+  private native void prev0(long handle);
 }

java/rocksjni/iterator.cc

@@ -30,6 +30,30 @@ void Java_org_rocksdb_Iterator_seekToFirst0(
   st->SeekToFirst();
 }
 
+void Java_org_rocksdb_Iterator_seekToLast0(
+    JNIEnv* env, jobject jobj, jlong handle) {
+  auto st = reinterpret_cast<rocksdb::Iterator*>(handle);
+  assert(st != nullptr);
+  
+  st->SeekToLast();
+}
+
+void Java_org_rocksdb_Iterator_next0(
+    JNIEnv* env, jobject jobj, jlong handle) {
+  auto st = reinterpret_cast<rocksdb::Iterator*>(handle);
+  assert(st != nullptr);
+  
+  st->Next();
+}
+
+void Java_org_rocksdb_Iterator_prev0(
+    JNIEnv* env, jobject jobj, jlong handle) {
+  auto st = reinterpret_cast<rocksdb::Iterator*>(handle);
+  assert(st != nullptr);
+  
+  st->Prev();
+}
+
 void Java_org_rocksdb_Iterator_close0(
     JNIEnv* env, jobject jobj, jlong handle) {
   auto st = reinterpret_cast<rocksdb::Iterator*>(handle);