Added constructors for serialization of the new constraint types and registered the types with the serializer pool.
diff --git a/core/api/src/main/java/org/onlab/onos/net/intent/constraint/LambdaConstraint.java b/core/api/src/main/java/org/onlab/onos/net/intent/constraint/LambdaConstraint.java
index d1d33d6..ab88c92 100644
--- a/core/api/src/main/java/org/onlab/onos/net/intent/constraint/LambdaConstraint.java
+++ b/core/api/src/main/java/org/onlab/onos/net/intent/constraint/LambdaConstraint.java
@@ -41,6 +41,11 @@
         this.lambda = lambda;
     }
 
+    // Constructor for serialization
+    private LambdaConstraint() {
+        this.lambda = null;
+    }
+
     @Override
     public boolean isValid(Link link, LinkResourceService resourceService) {
         for (ResourceRequest request : resourceService.getAvailableResources(link)) {