Added a number of container classes that will be used for
Flow Path computation and installation.
diff --git a/src/main/java/net/floodlightcontroller/util/CallerId.java b/src/main/java/net/floodlightcontroller/util/CallerId.java
new file mode 100644
index 0000000..898da31
--- /dev/null
+++ b/src/main/java/net/floodlightcontroller/util/CallerId.java
@@ -0,0 +1,48 @@
+package net.floodlightcontroller.util;
+
+/**
+ * The class representing a Caller ID for an ONOS component.
+ */
+public class CallerId {
+    private String value;
+
+    /**
+     * Default constructor.
+     */
+    public CallerId() {}
+
+    /**
+     * Constructor from a string value.
+     *
+     * @param value the value to use.
+     */
+    public CallerId(String value) {
+	this.value = value;
+    }
+
+    /**
+     * Get the value of the Caller ID.
+     *
+     * @return the value of the Caller ID.
+     */
+    public String value() { return value; }
+
+    /**
+     * Set the value of the Caller ID.
+     *
+     * @param value the value to set.
+     */
+    public void setValue(String value) {
+	this.value = value;
+    }
+
+    /**
+     * Convert the Caller ID value to a string.
+     *
+     * @return the Caller ID value to a string.
+     */
+    @Override
+    public String toString() {
+	return value;
+    }
+}