Define Lambda interface representing wavelength and implementations

Two Lambda implementations are defined.
- IndexedLambda
- OchSignal

Change-Id: I36763390f61abd9f861e76edab63f558ae97e8a2
diff --git a/core/api/src/main/java/org/onosproject/net/IndexedLambda.java b/core/api/src/main/java/org/onosproject/net/IndexedLambda.java
new file mode 100644
index 0000000..e350b47
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/net/IndexedLambda.java
@@ -0,0 +1,60 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * 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.onosproject.net;
+
+import com.google.common.base.MoreObjects;
+
+/**
+ * Implementation of Lambda simply designated by an index number of wavelength.
+ */
+public class IndexedLambda implements Lambda {
+
+    private final long lambda;
+
+    /**
+     * Creates an instance representing the wavelength specified by the given index number.
+     *
+     * @param lambda index number of wavelength
+     */
+    IndexedLambda(long lambda) {
+        this.lambda = lambda;
+    }
+
+    @Override
+    public int hashCode() {
+        return (int) (lambda ^ (lambda >>> 32));
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (!(obj instanceof IndexedLambda)) {
+            return false;
+        }
+
+        final IndexedLambda that = (IndexedLambda) obj;
+        return this.lambda == that.lambda;
+    }
+
+    @Override
+    public String toString() {
+        return MoreObjects.toStringHelper(this)
+                .add("lambda", lambda)
+                .toString();
+    }
+}