Guard malformed intent by pre-condition check on instantiation

Change-Id: I90ca0fac2e3b68c4ca5b464777b0cdaa2227c2e5

@@ -71,6 +71,8 @@ public final class HostToHostIntent extends ConnectivityIntent {
         super(id(HostToHostIntent.class, min(one, two), max(one, two),
                  selector, treatment, constraints),
               appId, null, selector, treatment, constraints);
+
+        // TODO: consider whether the case one and two are same is allowed
         this.one = checkNotNull(one);
         this.two = checkNotNull(two);
 

@@ -86,9 +86,12 @@ public final class MultiPointToSinglePointIntent extends ConnectivityIntent {
 
         checkNotNull(ingressPoints);
         checkArgument(!ingressPoints.isEmpty(), "Ingress point set cannot be empty");
+        checkNotNull(egressPoint);
+        checkArgument(!ingressPoints.contains(egressPoint),
+                "Set of ingresses should not contain egress (egress: %s)", egressPoint);
 
         this.ingressPoints = Sets.newHashSet(ingressPoints);
-        this.egressPoint = checkNotNull(egressPoint);
+        this.egressPoint = egressPoint;
     }
 
     /**

@@ -26,6 +26,7 @@ import org.onlab.onos.net.intent.constraint.LinkTypeConstraint;
 
 import java.util.List;
 
+import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkNotNull;
 
 /**
@@ -75,8 +76,14 @@ public class PointToPointIntent extends ConnectivityIntent {
         super(id(PointToPointIntent.class, selector, treatment,
                  ingressPoint, egressPoint, constraints),
               appId, null, selector, treatment, constraints);
-        this.ingressPoint = checkNotNull(ingressPoint);
-        this.egressPoint = checkNotNull(egressPoint);
+
+        checkNotNull(ingressPoint);
+        checkNotNull(egressPoint);
+        checkArgument(!ingressPoint.equals(egressPoint),
+                "ingress and egress should be different (ingress: %s, egress: %s)", ingressPoint, egressPoint);
+
+        this.ingressPoint = ingressPoint;
+        this.egressPoint = egressPoint;
     }
 
     /**

@@ -56,8 +56,12 @@ public class SinglePointToMultiPointIntent extends ConnectivityIntent {
         super(id(SinglePointToMultiPointIntent.class, selector, treatment,
                  ingressPoint, egressPoints), appId, null, selector, treatment);
         checkNotNull(egressPoints);
+        checkNotNull(ingressPoint);
         checkArgument(!egressPoints.isEmpty(), "Egress point set cannot be empty");
-        this.ingressPoint = checkNotNull(ingressPoint);
+        checkArgument(!egressPoints.contains(ingressPoint),
+                "Set of egresses should not contain ingress (ingress: %s)", ingressPoint);
+
+        this.ingressPoint = ingressPoint;
         this.egressPoints = Sets.newHashSet(egressPoints);
     }