Adding iterator JNI binding

java/org/rocksdb/Iterator.java

@@ -0,0 +1,42 @@
+// 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;
+
+public class Iterator {
+  private long nativeHandle_;
+  
+  public Iterator(long nativeHandle) {
+    nativeHandle_ = nativeHandle;
+  }
+  
+  public boolean isValid() {
+    assert(isInitialized());
+    return isValid0(nativeHandle_);
+  }
+  
+  public void seekToFirst() {
+    assert(isInitialized());
+    seekToFirst0(nativeHandle_);
+  }
+  
+  public synchronized void close() {
+    if(nativeHandle_ != 0) {
+      close0(nativeHandle_);
+    }
+  }
+  
+  @Override protected void finalize() {
+    close();
+  }
+  
+  private boolean isInitialized() {
+    return (nativeHandle_ != 0);
+  }
+  
+  private native boolean isValid0(long handle);
+  private native void close0(long handle);
+  private native void seekToFirst0(long handle);
+}