Initial implementation of async installers
diff --git a/core/net/src/main/java/org/onlab/onos/net/intent/impl/IntentManager.java b/core/net/src/main/java/org/onlab/onos/net/intent/impl/IntentManager.java
index 16b75f2..50f1038 100644
--- a/core/net/src/main/java/org/onlab/onos/net/intent/impl/IntentManager.java
+++ b/core/net/src/main/java/org/onlab/onos/net/intent/impl/IntentManager.java
@@ -13,12 +13,14 @@
 import static org.slf4j.LoggerFactory.getLogger;
 
 import java.util.ArrayList;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Future;
 
 import org.apache.felix.scr.annotations.Activate;
 import org.apache.felix.scr.annotations.Component;
@@ -28,6 +30,7 @@
 import org.apache.felix.scr.annotations.Service;
 import org.onlab.onos.event.AbstractListenerRegistry;
 import org.onlab.onos.event.EventDeliveryService;
+import org.onlab.onos.net.flow.CompletedBatchOperation;
 import org.onlab.onos.net.intent.InstallableIntent;
 import org.onlab.onos.net.intent.Intent;
 import org.onlab.onos.net.intent.IntentCompiler;
@@ -44,7 +47,9 @@
 import org.onlab.onos.net.intent.IntentStoreDelegate;
 import org.slf4j.Logger;
 
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Lists;
 
 /**
  * An implementation of Intent Manager.
@@ -67,7 +72,8 @@
     private final AbstractListenerRegistry<IntentEvent, IntentListener>
             listenerRegistry = new AbstractListenerRegistry<>();
 
-    private final ExecutorService executor = newSingleThreadExecutor(namedThreads("onos-intents"));
+    private ExecutorService executor;
+    private ExecutorService monitorExecutor;
 
     private final IntentStoreDelegate delegate = new InternalStoreDelegate();
     private final TopologyChangeDelegate topoDelegate = new InternalTopoChangeDelegate();
@@ -86,6 +92,8 @@
         store.setDelegate(delegate);
         trackerService.setDelegate(topoDelegate);
         eventDispatcher.addSink(IntentEvent.class, listenerRegistry);
+        executor = newSingleThreadExecutor(namedThreads("onos-intents"));
+        monitorExecutor = newSingleThreadExecutor(namedThreads("onos-intent-monitor"));
         log.info("Started");
     }
 
@@ -94,6 +102,8 @@
         store.unsetDelegate(delegate);
         trackerService.unsetDelegate(topoDelegate);
         eventDispatcher.removeSink(IntentEvent.class);
+        executor.shutdown();
+        monitorExecutor.shutdown();
         log.info("Stopped");
     }
 
@@ -240,14 +250,23 @@
         }
     }
 
-    // FIXME: To make SDN-IP workable ASAP, only single level compilation is implemented
-    // TODO: implement compilation traversing tree structure
+    /**
+     * Compiles an intent recursively.
+     *
+     * @param intent intent
+     * @return result of compilation
+     */
     private List<InstallableIntent> compileIntent(Intent intent) {
-        List<InstallableIntent> installable = new ArrayList<>();
-        for (Intent compiled : getCompiler(intent).compile(intent)) {
-            InstallableIntent installableIntent = (InstallableIntent) compiled;
-            installable.add(installableIntent);
+        if (intent instanceof InstallableIntent) {
+            return ImmutableList.of((InstallableIntent) intent);
         }
+
+        List<InstallableIntent> installable = new ArrayList<>();
+        // TODO do we need to registerSubclassCompiler?
+        for (Intent compiled : getCompiler(intent).compile(intent)) {
+            installable.addAll(compileIntent(compiled));
+        }
+
         return installable;
     }
 
@@ -261,6 +280,7 @@
         // Indicate that the intent is entering the installing phase.
         store.setState(intent, INSTALLING);
 
+        List<Future<CompletedBatchOperation>> installFutures = Lists.newArrayList();
         try {
             List<InstallableIntent> installables = store.getInstallableIntents(intent.id());
             if (installables != null) {
@@ -268,17 +288,20 @@
                     registerSubclassInstallerIfNeeded(installable);
                     trackerService.addTrackedResources(intent.id(),
                                                        installable.requiredLinks());
-                    getInstaller(installable).install(installable);
+                    Future<CompletedBatchOperation> future = getInstaller(installable).install(installable);
+                    installFutures.add(future);
                 }
             }
-            eventDispatcher.post(store.setState(intent, INSTALLED));
-
+            // FIXME we have to wait for the installable intents
+            //eventDispatcher.post(store.setState(intent, INSTALLED));
+            monitorExecutor.execute(new IntentInstallMonitor(intent, installFutures, INSTALLED));
         } catch (Exception e) {
             log.warn("Unable to install intent {} due to: {}", intent.id(), e);
-            uninstallIntent(intent);
+            uninstallIntent(intent, RECOMPILING);
 
             // If compilation failed, kick off the recompiling phase.
-            executeRecompilingPhase(intent);
+            // FIXME
+            //executeRecompilingPhase(intent);
         }
     }
 
@@ -327,12 +350,14 @@
     private void executeWithdrawingPhase(Intent intent) {
         // Indicate that the intent is being withdrawn.
         store.setState(intent, WITHDRAWING);
-        uninstallIntent(intent);
+        uninstallIntent(intent, WITHDRAWN);
 
         // If all went well, disassociate the top-level intent with its
         // installable derivatives and mark it as withdrawn.
-        store.removeInstalledIntents(intent.id());
-        eventDispatcher.post(store.setState(intent, WITHDRAWN));
+        // FIXME need to clean up
+        //store.removeInstalledIntents(intent.id());
+        // FIXME
+        //eventDispatcher.post(store.setState(intent, WITHDRAWN));
     }
 
     /**
@@ -340,14 +365,17 @@
      *
      * @param intent intent to be uninstalled
      */
-    private void uninstallIntent(Intent intent) {
+    private void uninstallIntent(Intent intent, IntentState nextState) {
+        List<Future<CompletedBatchOperation>> uninstallFutures = Lists.newArrayList();
         try {
             List<InstallableIntent> installables = store.getInstallableIntents(intent.id());
             if (installables != null) {
                 for (InstallableIntent installable : installables) {
-                    getInstaller(installable).uninstall(installable);
+                    Future<CompletedBatchOperation> future = getInstaller(installable).uninstall(installable);
+                    uninstallFutures.add(future);
                 }
             }
+            monitorExecutor.execute(new IntentInstallMonitor(intent, uninstallFutures, nextState));
         } catch (IntentException e) {
             log.warn("Unable to uninstall intent {} due to: {}", intent.id(), e);
         }
@@ -422,9 +450,10 @@
             // Attempt recompilation of the specified intents first.
             for (IntentId intentId : intentIds) {
                 Intent intent = getIntent(intentId);
-                uninstallIntent(intent);
+                uninstallIntent(intent, RECOMPILING);
 
-                executeRecompilingPhase(intent);
+                //FIXME
+                //executeRecompilingPhase(intent);
             }
 
             if (compileAllFailed) {
@@ -460,4 +489,44 @@
         }
     }
 
+    private class IntentInstallMonitor implements Runnable {
+
+        private final Intent intent;
+        private final List<Future<CompletedBatchOperation>> futures;
+        private final IntentState nextState;
+
+        public IntentInstallMonitor(Intent intent,
+                List<Future<CompletedBatchOperation>> futures, IntentState nextState) {
+            this.intent = intent;
+            this.futures = futures;
+            this.nextState = nextState;
+        }
+
+        private void updateIntent(Intent intent) {
+            if (nextState == RECOMPILING) {
+                executor.execute(new IntentTask(nextState, intent));
+            } else if (nextState == INSTALLED || nextState == WITHDRAWN) {
+                eventDispatcher.post(store.setState(intent, nextState));
+            } else {
+                log.warn("Invalid next intent state {} for intent {}", nextState, intent);
+            }
+        }
+
+        @Override
+        public void run() {
+            for (Iterator<Future<CompletedBatchOperation>> i = futures.iterator(); i.hasNext();) {
+                Future<CompletedBatchOperation> future = i.next();
+                if (future.isDone()) {
+                    // TODO: we may want to get the future here
+                    i.remove();
+                }
+            }
+            if (futures.isEmpty()) {
+                updateIntent(intent);
+            } else {
+                // resubmit ourselves if we are not done yet
+                monitorExecutor.submit(this);
+            }
+        }
+    }
 }