Make providers lazy

7 files changed, 36 insertions, 32 deletions

diff --git a/container-di/src/main/java/com/yahoo/container/di/CloudSubscriberFactory.java b/container-di/src/main/java/com/yahoo/container/di/CloudSubscriberFactory.java
index 3f3991760e3..0851f69a366 100644
--- a/container-di/src/main/java/com/yahoo/container/di/CloudSubscriberFactory.java
+++ b/container-di/src/main/java/com/yahoo/container/di/CloudSubscriberFactory.java
@@ -26,6 +26,7 @@ import java.util.logging.Logger;
  * @author ollivir
  */
 public class CloudSubscriberFactory implements SubscriberFactory {
+
     private static final Logger log = Logger.getLogger(CloudSubscriberFactory.class.getName());
 
     private final ConfigSource configSource;
@@ -46,7 +47,7 @@ public class CloudSubscriberFactory implements SubscriberFactory {
         }
         CloudSubscriber subscriber = new CloudSubscriber(subscriptionKeys, configSource);
 
-        testGeneration.ifPresent(subscriber.subscriber::reload); //TODO: test specific code, remove
+        testGeneration.ifPresent(subscriber.subscriber::reload); // TODO: test specific code, remove
         activeSubscribers.put(subscriber, 0);
 
         return subscriber;
@@ -112,7 +113,7 @@ public class CloudSubscriberFactory implements SubscriberFactory {
              * component is removed, so this old config generation will soon be replaced by a new one. */
             boolean gotNextGen = false;
             int numExceptions = 0;
-            while (!gotNextGen) {
+            while ( ! gotNextGen) {
                 try {
                     if (subscriber.nextGeneration()) {
                         gotNextGen = true;
@@ -136,8 +137,8 @@ public class CloudSubscriberFactory implements SubscriberFactory {
         public void close() {
             subscriber.close();
         }
-    }
 
+    }
 
     public static class Provider implements com.google.inject.Provider<SubscriberFactory> {
         @Override
@@ -145,4 +146,5 @@ public class CloudSubscriberFactory implements SubscriberFactory {
             return new CloudSubscriberFactory(ConfigSourceSet.createDefault());
         }
     }
+
 }
diff --git a/container-di/src/main/java/com/yahoo/container/di/Container.java b/container-di/src/main/java/com/yahoo/container/di/Container.java
index 50e87cd9db6..24e5dcef838 100644
--- a/container-di/src/main/java/com/yahoo/container/di/Container.java
+++ b/container-di/src/main/java/com/yahoo/container/di/Container.java
@@ -67,8 +67,8 @@ public class Container {
 
     private void deconstructObsoleteComponents(ComponentGraph oldGraph, ComponentGraph newGraph) {
         IdentityHashMap<Object, Object> oldComponents = new IdentityHashMap<>();
-        oldGraph.allComponentsAndProviders().forEach(c -> oldComponents.put(c, null));
-        newGraph.allComponentsAndProviders().forEach(oldComponents::remove);
+        oldGraph.allConstructedComponentsAndProviders().forEach(c -> oldComponents.put(c, null));
+        newGraph.allConstructedComponentsAndProviders().forEach(oldComponents::remove);
         oldComponents.keySet().forEach(componentDeconstructor::deconstruct);
     }
 
@@ -226,7 +226,7 @@ public class Container {
     }
 
     private void constructComponents(ComponentGraph graph) {
-        graph.nodes().forEach(Node::newOrCachedInstance);
+        graph.nodes().forEach(Node::constructInstance);
     }
 
     public void shutdown(ComponentGraph graph, ComponentDeconstructor deconstructor) {
@@ -246,7 +246,7 @@ public class Container {
     }
 
     private void deconstructAllComponents(ComponentGraph graph, ComponentDeconstructor deconstructor) {
-        graph.allComponentsAndProviders().forEach(deconstructor::deconstruct);
+        graph.allConstructedComponentsAndProviders().forEach(deconstructor::deconstruct);
     }
 
     public static <T extends ConfigInstance> T getConfig(ConfigKey<T> key,
diff --git a/container-di/src/main/java/com/yahoo/container/di/componentgraph/core/ComponentGraph.java b/container-di/src/main/java/com/yahoo/container/di/componentgraph/core/ComponentGraph.java
index 76ca94c9286..4a0598d3436 100644
--- a/container-di/src/main/java/com/yahoo/container/di/componentgraph/core/ComponentGraph.java
+++ b/container-di/src/main/java/com/yahoo/container/di/componentgraph/core/ComponentGraph.java
@@ -43,6 +43,7 @@ import static com.yahoo.container.di.componentgraph.core.Exceptions.removeStackT
  */
 @NotThreadSafe
 public class ComponentGraph {
+
     private static final Logger log = Logger.getLogger(ComponentGraph.class.getName());
 
     private long generation;
@@ -107,7 +108,7 @@ public class ComponentGraph {
     @SuppressWarnings("unchecked")
     public <T> T getInstance(Key<T> key) {
         // TODO: Combine exception handling with lookupGlobalComponent.
-        Object ob = lookupGlobalComponent(key).map(Node::newOrCachedInstance)
+        Object ob = lookupGlobalComponent(key).map(Node::component)
                 .orElseThrow(() -> new IllegalStateException(String.format("No global component with key '%s'  ", key)));
         return (T) ob;
     }
@@ -162,8 +163,8 @@ public class ComponentGraph {
         }
     }
 
-    public Collection<?> allComponentsAndProviders() {
-        return nodes().stream().map(node -> node.instance().get()).collect(Collectors.toList());
+    public Collection<?> allConstructedComponentsAndProviders() {
+        return nodes().stream().map(node -> node.constructedInstance().get()).collect(Collectors.toList());
     }
 
     private void completeComponentRegistryNode(ComponentRegistryNode registry) {
@@ -243,7 +244,7 @@ public class ComponentGraph {
     }
 
     private Optional<GuiceNode> matchingGuiceNode(Key<?> key, Object instance) {
-        return matchingNodes(nodes(), GuiceNode.class, key).stream().filter(node -> node.newOrCachedInstance() == instance). // TODO: assert that there is only one (after filter)
+        return matchingNodes(nodes(), GuiceNode.class, key).stream().filter(node -> node.component() == instance). // TODO: assert that there is only one (after filter)
                 findFirst();
     }
 
diff --git a/container-di/src/main/java/com/yahoo/container/di/componentgraph/core/ComponentNode.java b/container-di/src/main/java/com/yahoo/container/di/componentgraph/core/ComponentNode.java
index dbe8ded550b..911cd5ffd02 100644
--- a/container-di/src/main/java/com/yahoo/container/di/componentgraph/core/ComponentNode.java
+++ b/container-di/src/main/java/com/yahoo/container/di/componentgraph/core/ComponentNode.java
@@ -138,7 +138,7 @@ public class ComponentNode extends Node {
         List<Object> actualArguments = new ArrayList<>();
         for (Object ob : arguments) {
             if (ob instanceof Node) {
-                actualArguments.add(((Node) ob).newOrCachedInstance());
+                actualArguments.add(((Node) ob).component());
             } else if (ob instanceof ConfigKey) {
                 actualArguments.add(availableConfigs.get(ob));
             } else {
diff --git a/container-di/src/main/java/com/yahoo/container/di/componentgraph/core/ComponentRegistryNode.java b/container-di/src/main/java/com/yahoo/container/di/componentgraph/core/ComponentRegistryNode.java
index 8af1713c84f..429052c0039 100644
--- a/container-di/src/main/java/com/yahoo/container/di/componentgraph/core/ComponentRegistryNode.java
+++ b/container-di/src/main/java/com/yahoo/container/di/componentgraph/core/ComponentRegistryNode.java
@@ -19,6 +19,7 @@ import java.util.stream.Collectors;
  * @author ollivir
  */
 public class ComponentRegistryNode extends Node {
+
     private static ComponentId componentRegistryNamespace = ComponentId.fromString("ComponentRegistry");
 
     private final Class<?> componentClass;
@@ -36,7 +37,7 @@ public class ComponentRegistryNode extends Node {
     @Override
     protected Object newInstance() {
         ComponentRegistry<Object> registry = new ComponentRegistry<>();
-        componentsToInject.forEach(component -> registry.register(component.componentId(), component.newOrCachedInstance()));
+        componentsToInject.forEach(component -> registry.register(component.componentId(), component.component()));
 
         return registry;
     }
@@ -102,4 +103,5 @@ public class ComponentRegistryNode extends Node {
             return false;
         }
     }
+
 }
diff --git a/container-di/src/main/java/com/yahoo/container/di/componentgraph/core/JerseyNode.java b/container-di/src/main/java/com/yahoo/container/di/componentgraph/core/JerseyNode.java
index 79b849bff8f..0f8aa678934 100644
--- a/container-di/src/main/java/com/yahoo/container/di/componentgraph/core/JerseyNode.java
+++ b/container-di/src/main/java/com/yahoo/container/di/componentgraph/core/JerseyNode.java
@@ -47,7 +47,7 @@ public class JerseyNode extends ComponentNode {
         }
 
         componentsToInject.forEach(component -> restApiContext.addInjectableComponent(component.instanceKey(), component.componentId(),
-                component.newOrCachedInstance()));
+                component.component()));
 
         return restApiContext;
     }
diff --git a/container-di/src/main/java/com/yahoo/container/di/componentgraph/core/Node.java b/container-di/src/main/java/com/yahoo/container/di/componentgraph/core/Node.java
index 6feac7a4078..9ed89a6091a 100644
--- a/container-di/src/main/java/com/yahoo/container/di/componentgraph/core/Node.java
+++ b/container-di/src/main/java/com/yahoo/container/di/componentgraph/core/Node.java
@@ -24,6 +24,7 @@ import static com.yahoo.log.LogLevel.SPAM;
  * @author ollivir
  */
 public abstract class Node {
+
     private final static Logger log = Logger.getLogger(Node.class.getName());
 
     private final ComponentId componentId;
@@ -43,25 +44,23 @@ public abstract class Node {
 
     protected abstract Object newInstance();
 
-    public Object newOrCachedInstance() {
-        Object inst;
-        if (instance.isPresent()) {
-            inst = instance.get();
-            log.log(SPAM, "Reusing instance for component with ID " + componentId);
-        } else {
-            log.log(DEBUG, "Creating new instance for component with ID " + componentId);
-            inst = newInstance();
-            instance = Optional.of(inst);
-        }
-        return component(inst);
+    /** Constructs the instance represented by this node, if not already done. */
+    public void constructInstance() {
+        if ( ! instance.isPresent())
+            instance = Optional.of(newInstance());
     }
 
-    private Object component(Object instance) {
-        if (instance instanceof Provider) {
-            Provider<?> provider = (Provider<?>) instance;
+    /**
+     * Returns the component represented by this - which is either the instance, or if the instance is a provider,
+     * the component returned by it.
+     */
+    public Object component() {
+        constructInstance();
+        if (instance.get() instanceof Provider) {
+            Provider<?> provider = (Provider<?>) instance.get();
             return provider.get();
         } else {
-            return instance;
+            return instance.get();
         }
     }
 
@@ -139,13 +138,13 @@ public abstract class Node {
         return componentId;
     }
 
-    public Optional<?> instance() {
+    /** Returns the already constructed instance in this, if any */
+    public Optional<?> constructedInstance() {
         return instance;
     }
 
     /**
-     * @param identityObject
-     *            The identifying object that makes the Node unique
+     * @param identityObject he identifying object that makes the Node unique
      */
     protected static ComponentId syntheticComponentId(String className, Object identityObject, ComponentId namespace) {
         String name = className + "_" + System.identityHashCode(identityObject);