diff --git a/java/src/com/android/inputmethod/latin/makedict/BinaryDictReader.java b/java/src/com/android/inputmethod/latin/makedict/BinaryDictReader.java
index 57a5832..a4a7ce4 100644
--- a/java/src/com/android/inputmethod/latin/makedict/BinaryDictReader.java
+++ b/java/src/com/android/inputmethod/latin/makedict/BinaryDictReader.java
@@ -24,6 +24,7 @@
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.io.RandomAccessFile;
 import java.nio.ByteBuffer;
 import java.nio.channels.FileChannel;
 
@@ -82,6 +83,32 @@
         }
     }
 
+    /**
+     * Creates FusionDictionaryBuffer from a RandomAccessFile.
+     */
+    @UsedForTesting
+    public static final class FusionDictionaryBufferFromWritableByteBufferFactory
+            implements FusionDictionaryBufferFactory {
+        @Override
+        public FusionDictionaryBufferInterface getFusionDictionaryBuffer(final File file)
+                throws FileNotFoundException, IOException {
+            RandomAccessFile raFile = null;
+            ByteBuffer buffer = null;
+            try {
+                raFile = new RandomAccessFile(file, "rw");
+                buffer = raFile.getChannel().map(FileChannel.MapMode.READ_WRITE, 0, file.length());
+            } finally {
+                if (raFile != null) {
+                    raFile.close();
+                }
+            }
+            if (buffer != null) {
+                return new BinaryDictInputOutput.ByteBufferWrapper(buffer);
+            }
+            return null;
+        }
+    }
+
     private final File mDictionaryBinaryFile;
     private FusionDictionaryBufferInterface mFusionDictionaryBuffer;
 
diff --git a/tests/src/com/android/inputmethod/latin/makedict/BinaryDictReaderTests.java b/tests/src/com/android/inputmethod/latin/makedict/BinaryDictReaderTests.java
index 5f6950a..a46e583 100644
--- a/tests/src/com/android/inputmethod/latin/makedict/BinaryDictReaderTests.java
+++ b/tests/src/com/android/inputmethod/latin/makedict/BinaryDictReaderTests.java
@@ -18,8 +18,12 @@
 
 import com.android.inputmethod.latin.makedict.BinaryDictInputOutput.FusionDictionaryBufferInterface;
 import com.android.inputmethod.latin.makedict.BinaryDictReader.FusionDictionaryBufferFactory;
-import com.android.inputmethod.latin.makedict.BinaryDictReader.FusionDictionaryBufferFromByteArrayFactory;
-import com.android.inputmethod.latin.makedict.BinaryDictReader.FusionDictionaryBufferFromByteBufferFactory;
+import com.android.inputmethod.latin.makedict.BinaryDictReader.
+        FusionDictionaryBufferFromByteArrayFactory;
+import com.android.inputmethod.latin.makedict.BinaryDictReader.
+        FusionDictionaryBufferFromByteBufferFactory;
+import com.android.inputmethod.latin.makedict.BinaryDictReader.
+        FusionDictionaryBufferFromWritableByteBufferFactory;
 
 import android.test.AndroidTestCase;
 import android.util.Log;
@@ -94,6 +98,11 @@
                 new FusionDictionaryBufferFromByteArrayFactory());
     }
 
+    public void testOpenBufferWithWritableByteBuffer() {
+        runTestOpenBuffer("testOpenBufferWithWritableByteBuffer",
+                new FusionDictionaryBufferFromWritableByteBufferFactory());
+    }
+
     @SuppressWarnings("null")
     public void runTestGetBuffer(final String testName,
             final FusionDictionaryBufferFactory factory) {
@@ -135,4 +144,9 @@
         runTestGetBuffer("testGetBufferWithByteArray",
                 new FusionDictionaryBufferFromByteArrayFactory());
     }
+
+    public void testGetBufferWithWritableByteBuffer() {
+        runTestGetBuffer("testGetBufferWithWritableByteBuffer",
+                new FusionDictionaryBufferFromWritableByteBufferFactory());
+    }
 }