Adding JSON output for intent list command.

 package org.onlab.onos.cli.net;
 
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ArrayNode;
+import com.fasterxml.jackson.databind.node.ObjectNode;
 import org.apache.karaf.shell.commands.Command;
 import org.onlab.onos.cli.AbstractShellCommand;
+import org.onlab.onos.net.ConnectPoint;
+import org.onlab.onos.net.Link;
+import org.onlab.onos.net.NetworkResource;
+import org.onlab.onos.net.intent.ConnectivityIntent;
 import org.onlab.onos.net.intent.Intent;
 import org.onlab.onos.net.intent.IntentService;
 import org.onlab.onos.net.intent.IntentState;
+import org.onlab.onos.net.intent.LinkCollectionIntent;
+import org.onlab.onos.net.intent.MultiPointToSinglePointIntent;
+import org.onlab.onos.net.intent.PathIntent;
+import org.onlab.onos.net.intent.PointToPointIntent;
+import org.onlab.onos.net.intent.SinglePointToMultiPointIntent;
+
+import java.util.Set;
 
 /**
  * Lists the inventory of intents and their states.
@@ -16,11 +31,120 @@ public class IntentsListCommand extends AbstractShellCommand {
     @Override
     protected void execute() {
         IntentService service = get(IntentService.class);
+        if (outputJson()) {
+            print("%s", json(service, service.getIntents()));
+        } else {
             for (Intent intent : service.getIntents()) {
                 IntentState state = service.getIntentState(intent.id());
-            print("id=%s, state=%s, appId=%s, %s",
-                  intent.id(), state, intent.appId().name(), intent);
+                print("id=%s, state=%s, type=%s, appId=%s",
+                      intent.id(), state, intent.getClass().getSimpleName(),
+                      intent.appId().name());
+                printDetails(intent);
+            }
+        }
+    }
+
+    private void printDetails(Intent intent) {
+        if (intent.resources() != null && !intent.resources().isEmpty()) {
+            print("    resources=%s", intent.resources());
+        }
+        if (intent instanceof ConnectivityIntent) {
+            ConnectivityIntent ci = (ConnectivityIntent) intent;
+            print("    selector=%s", ci.selector().criteria());
+            print("    treatment=%s", ci.treatment().instructions());
+        }
+
+        if (intent instanceof PointToPointIntent) {
+            PointToPointIntent pi = (PointToPointIntent) intent;
+            print("    ingress=%s, egress=%s", pi.ingressPoint(), pi.egressPoint());
+        } else if (intent instanceof MultiPointToSinglePointIntent) {
+            MultiPointToSinglePointIntent pi = (MultiPointToSinglePointIntent) intent;
+            print("    ingress=%s, egress=%s", pi.ingressPoints(), pi.egressPoint());
+        } else if (intent instanceof SinglePointToMultiPointIntent) {
+            SinglePointToMultiPointIntent pi = (SinglePointToMultiPointIntent) intent;
+            print("    ingress=%s, egress=%s", pi.ingressPoint(), pi.egressPoints());
+        } else if (intent instanceof PathIntent) {
+            PathIntent pi = (PathIntent) intent;
+            print("    path=%s, cost=%d", pi.path().links(), pi.path().cost());
+        } else if (intent instanceof LinkCollectionIntent) {
+            LinkCollectionIntent li = (LinkCollectionIntent) intent;
+            print("    links=%s", li.links());
+            print("    egress=%s", li.egressPoint());
+        }
+    }
+
+    // Produces JSON array of the specified intents.
+    private JsonNode json(IntentService service, Iterable<Intent> intents) {
+        ObjectMapper mapper = new ObjectMapper();
+        ArrayNode result = mapper.createArrayNode();
+        for (Intent intent : intents) {
+            result.add(json(service, mapper, intent));
+        }
+        return result;
+    }
+
+    private JsonNode json(IntentService service, ObjectMapper mapper, Intent intent) {
+        ObjectNode result = mapper.createObjectNode()
+                .put("id", intent.id().toString())
+                .put("state", service.getIntentState(intent.id()).toString())
+                .put("type", intent.getClass().getSimpleName())
+                .put("appId", intent.appId().name());
+
+        if (intent.resources() != null && !intent.resources().isEmpty()) {
+            ArrayNode rnode = mapper.createArrayNode();
+            for (NetworkResource resource : intent.resources()) {
+                rnode.add(resource.toString());
+            }
+            result.set("resources", rnode);
+        }
+
+        if (intent instanceof ConnectivityIntent) {
+            ConnectivityIntent ci = (ConnectivityIntent) intent;
+            if (!ci.selector().criteria().isEmpty()) {
+                result.put("selector", ci.selector().criteria().toString());
+            }
+            if (!ci.treatment().instructions().isEmpty()) {
+                result.put("treatment", ci.treatment().instructions().toString());
+            }
+        }
+
+        if (intent instanceof PathIntent) {
+            PathIntent pi = (PathIntent) intent;
+            ArrayNode pnode = mapper.createArrayNode();
+            for (Link link : pi.path().links()) {
+                pnode.add(link.toString());
+            }
+            result.set("path", pnode);
+
+        } else if (intent instanceof PointToPointIntent) {
+            PointToPointIntent pi = (PointToPointIntent) intent;
+            result.set("ingress", LinksListCommand.json(mapper, pi.ingressPoint()));
+            result.set("egress", LinksListCommand.json(mapper, pi.egressPoint()));
+
+        } else if (intent instanceof MultiPointToSinglePointIntent) {
+            MultiPointToSinglePointIntent pi = (MultiPointToSinglePointIntent) intent;
+            result.set("ingress", json(mapper, pi.ingressPoints()));
+            result.set("egress", LinksListCommand.json(mapper, pi.egressPoint()));
+
+        } else if (intent instanceof SinglePointToMultiPointIntent) {
+            SinglePointToMultiPointIntent pi = (SinglePointToMultiPointIntent) intent;
+            result.set("ingress", LinksListCommand.json(mapper, pi.ingressPoint()));
+            result.set("egress", json(mapper, pi.egressPoints()));
+
+        } else if (intent instanceof LinkCollectionIntent) {
+            LinkCollectionIntent li = (LinkCollectionIntent) intent;
+            result.set("links", LinksListCommand.json(li.links()));
+        }
+
+        return result;
+    }
+
+    private JsonNode json(ObjectMapper mapper, Set<ConnectPoint> connectPoints) {
+        ArrayNode result = mapper.createArrayNode();
+        for (ConnectPoint cp : connectPoints) {
+            result.add(LinksListCommand.json(mapper, cp));
         }
+        return result;
     }
 
 }