diff --git a/apps/acl/src/main/java/org/onos/acl/RuleId.java b/apps/acl/src/main/java/org/onos/acl/RuleId.java
new file mode 100644
index 0000000..754a643
--- /dev/null
+++ b/apps/acl/src/main/java/org/onos/acl/RuleId.java
@@ -0,0 +1,85 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ * Originally created by Pengfei Lu, Network and Cloud Computing Laboratory, Dalian University of Technology, China
+ * Advisers: Keqiu Li and Heng Qi
+ * This work is supported by the State Key Program of National Natural Science of China(Grant No. 61432002)
+ * and Prospective Research Project on Future Networks in Jiangsu Future Networks Innovation Institute.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onos.acl;
+
+/**
+ * ACL rule identifier suitable as an external key.
+ * <p>This class is immutable.</p>
+ */
+public final class RuleId {
+    private final long value;
+
+    /**
+     * Creates an ACL rule identifier from the specified long value.
+     *
+     * @param value long value
+     * @return ACL rule identifier
+     */
+    public static RuleId valueOf(long value) {
+        return new RuleId(value);
+    }
+
+    /**
+     * Constructor for serializer.
+     */
+    RuleId() {
+        this.value = 0;
+    }
+
+    /**
+     * Constructs the ID corresponding to a given long value.
+     *
+     * @param value the underlying value of this ID
+     */
+    RuleId(long value) {
+        this.value = value;
+    }
+
+    /**
+     * Returns the backing value.
+     *
+     * @return the value
+     */
+    public long fingerprint() {
+        return value;
+    }
+
+    @Override
+    public int hashCode() {
+        return Long.hashCode(value);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj == this) {
+            return true;
+        }
+        if (!(obj instanceof RuleId)) {
+            return false;
+        }
+        RuleId that = (RuleId) obj;
+        return this.value == that.value;
+    }
+
+    @Override
+    public String toString() {
+        return "0x" + Long.toHexString(value);
+    }
+}