Tidy up.

Address code review comments.
Remove all safe calls from Kotlin tests.

components/proxy/src/main/java/com/hotels/styx/admin/handlers/RoutingObjectHandler.java

@@ -27,7 +27,7 @@
 import com.hotels.styx.api.HttpRequest;
 import com.hotels.styx.api.HttpResponse;
 import com.hotels.styx.api.WebServiceHandler;
-import com.hotels.styx.routing.RoutingObjectDecorator;
+import com.hotels.styx.routing.RoutingMetadataDecorator;
 import com.hotels.styx.routing.RoutingObjectRecord;
 import com.hotels.styx.routing.config.Builtins;
 import com.hotels.styx.routing.config.RoutingObjectFactory;
@@ -96,9 +96,9 @@ public RoutingObjectHandler(StyxObjectStore<RoutingObjectRecord> routeDatabase,
 
                     try {
                         RoutingObjectDefinition payload = YAML_MAPPER.readValue(body, RoutingObjectDefinition.class);
-                        RoutingObjectDecorator adapter = new RoutingObjectDecorator(Builtins.build(emptyList(), routingObjectFactoryContext, payload));
+                        RoutingMetadataDecorator decorator = new RoutingMetadataDecorator(Builtins.build(emptyList(), routingObjectFactoryContext, payload));
 
-                        routeDatabase.insert(name, new RoutingObjectRecord(payload.type(), ImmutableSet.copyOf(payload.tags()), payload.config(), adapter))
+                        routeDatabase.insert(name, new RoutingObjectRecord(payload.type(), ImmutableSet.copyOf(payload.tags()), payload.config(), decorator))
                                 .ifPresent(previous -> previous.getRoutingObject().stop());
 
                         return Eventual.of(response(CREATED).build());

components/proxy/src/main/java/com/hotels/styx/infrastructure/RegistryServiceAdapter.java

@@ -24,7 +24,7 @@
 import static java.util.Objects.requireNonNull;
 
 /**
- * RegistryServiceAdapter - add a description later.
+ * RegistryServiceAdapter adapts BackendService registry to a Styx Service.
  */
 public class RegistryServiceAdapter extends AbstractStyxService implements Registry<BackendService> {
     private Registry<BackendService> delegate;

components/proxy/src/main/java/com/hotels/styx/routing/RoutingObjectDecorator.java → components/proxy/src/main/java/com/hotels/styx/routing/RoutingMetadataDecorator.java

@@ -28,10 +28,11 @@
 import static java.util.Objects.requireNonNull;
 
 /**
- * Adapts routing object into Styx core.
- * Provides a load balancing metric for the adapted routing object.
+ * Decorates a RoutingObject instance with additional metadata. This includes, but not
+ * limited to, a load balancing metric. Styx core needs this metadata to use the
+ * routing object in the forwarding path.
  */
-public class RoutingObjectDecorator implements RoutingObject {
+public class RoutingMetadataDecorator implements RoutingObject {
 
     private final RoutingObject delegate;
 
@@ -42,7 +43,7 @@ public class RoutingObjectDecorator implements RoutingObject {
      * Routing object adapater constructor.
      * @param routingObject
      */
-    public RoutingObjectDecorator(RoutingObject routingObject) {
+    public RoutingMetadataDecorator(RoutingObject routingObject) {
         this.delegate = requireNonNull(routingObject);
     }
 

components/proxy/src/main/java/com/hotels/styx/routing/config/Builtins.java

@@ -40,9 +40,9 @@
 import static java.nio.charset.StandardCharsets.UTF_8;
 
 /**
- * Builds a routing object based on its actual type.
+ * Contains mappings of builtin routing object and interceptor names to their factory methods.
  */
-public class Builtins {
+public final class Builtins {
     public static final ImmutableMap<String, Schema.FieldType> BUILTIN_HANDLER_SCHEMAS;
     public static final ImmutableMap<String, RoutingObjectFactory> BUILTIN_HANDLER_FACTORIES;
     public static final RouteRefLookup DEFAULT_REFERENCE_LOOKUP = reference -> (request, ctx) ->
@@ -84,6 +84,9 @@ public class Builtins {
                 .build();
     }
 
+    private Builtins() {
+    }
+
     public static RoutingObject build(List<String> parents, RoutingObjectFactory.Context context, RoutingObjectConfiguration configNode) {
         if (configNode instanceof RoutingObjectDefinition) {
             RoutingObjectDefinition configBlock = (RoutingObjectDefinition) configNode;

components/proxy/src/main/java/com/hotels/styx/routing/config/RoutingObjectFactory.java

@@ -28,25 +28,24 @@
 import static java.util.Objects.requireNonNull;
 
 /**
- * A factory for constructing HTTP handler objects from a RoutingObjectDefinition yaml config block.
+ * A factory for constructing Styx routing objects from a RoutingObjectDefinition
+ * yaml config block.
  */
 public interface RoutingObjectFactory {
     /**
-     * Constructs a terminal action handler according to routing configuration block.
+     * Constructs a RoutingObject instance according to configuration block.
      * <p>
-     * Constructs a terminal action handler for the HTTP request. The handler is constructed
-     * according to the definition codified in the RoutingObjectDefinition instance.
-     * The RoutingObjectFactory is a factory object for constructing any dependant routing
-     * objects. The objectVariables is a map of already instantiated routing objects
-     * that can be referred from the handler being built.
+     * The routing object is constructed according to the definition codified in
+     * the RoutingObjectDefinition instance. Context provides access to
+     * core Styx components necessary for constructing dependant objects.
      * <p>
      *
-     * @param parents
-     * @param context
-     * @param configBlock
-     * @return
+     * @param fullName a fully qualified attribute name, including parents
+     * @param context a routing object factory context
+     * @param configBlock routing object configuration
+     * @return a RoutingObject with all dependant objects
      */
-    RoutingObject build(List<String> parents, Context context, RoutingObjectDefinition configBlock);
+    RoutingObject build(List<String> fullName, Context context, RoutingObjectDefinition configBlock);
 
     /**
      * Contextual information for factory class.

components/proxy/src/main/java/com/hotels/styx/routing/handlers/BackendServiceProxy.java

@@ -92,16 +92,16 @@ public Factory(Environment environment, Map<String, Registry<BackendService>> ba
         }
 
         @Override
-        public RoutingObject build(List<String> parents, Context context, RoutingObjectDefinition configBlock) {
+        public RoutingObject build(List<String> fullName, Context context, RoutingObjectDefinition configBlock) {
             JsonNodeConfig config = new JsonNodeConfig(configBlock.config());
             String provider = config.get("backendProvider")
-                    .orElseThrow(() -> missingAttributeError(configBlock, join(".", parents), "backendProvider"));
+                    .orElseThrow(() -> missingAttributeError(configBlock, join(".", fullName), "backendProvider"));
 
             Registry<BackendService> registry = backendRegistries.get(provider);
             if (registry == null) {
                 throw new IllegalArgumentException(
                         format("No such backend service provider exists, attribute='%s', name='%s'",
-                                join(".", append(parents, "backendProvider")), provider));
+                                join(".", append(fullName, "backendProvider")), provider));
             }
 
             PlatformAwareClientEventLoopGroupFactory factory = new PlatformAwareClientEventLoopGroupFactory("BackendServiceProxy", 0);

components/proxy/src/main/java/com/hotels/styx/routing/handlers/ConditionRouter.java

@@ -122,23 +122,23 @@ private static Route buildRoute(
         }
 
         @Override
-        public RoutingObject build(List<String> parents, Context context, RoutingObjectDefinition configBlock) {
+        public RoutingObject build(List<String> fullName, Context context, RoutingObjectDefinition configBlock) {
             ConditionRouterConfig config = new JsonNodeConfig(configBlock.config()).as(ConditionRouterConfig.class);
             if (config.routes == null) {
-                throw missingAttributeError(configBlock, join(".", parents), "routes");
+                throw missingAttributeError(configBlock, join(".", fullName), "routes");
             }
 
             AtomicInteger index = new AtomicInteger(0);
             List<Route> routes = config.routes.stream()
                     .map(routeConfig -> buildRoute(
-                            append(parents, "routes"),
+                            append(fullName, "routes"),
                             context,
                             index.getAndIncrement(),
                             routeConfig.condition,
                             routeConfig.destination))
                     .collect(Collectors.toList());
 
-            RoutingObject fallbackHandler = buildFallbackHandler(parents, context, config);
+            RoutingObject fallbackHandler = buildFallbackHandler(fullName, context, config);
 
             ConditionRouter router = new ConditionRouter(routes, fallbackHandler);
 

components/proxy/src/main/java/com/hotels/styx/routing/handlers/HostProxy.java

@@ -148,7 +148,7 @@ public static class Factory implements RoutingObjectFactory {
         private static final int DEFAULT_HTTP_PORT = 80;
 
         @Override
-        public RoutingObject build(List<String> parents, Context context, RoutingObjectDefinition configBlock) {
+        public RoutingObject build(List<String> fullName, Context context, RoutingObjectDefinition configBlock) {
             JsonNodeConfig config = new JsonNodeConfig(configBlock.config());
 
             ConnectionPoolSettings poolSettings = config.get("connectionPool", ConnectionPoolSettings.class)
@@ -166,7 +166,7 @@ public RoutingObject build(List<String> parents, Context context, RoutingObjectD
             HostAndPort hostAndPort = config.get("host")
                     .map(HostAndPort::fromString)
                     .map(it -> addDefaultPort(it, tlsSettings))
-                    .orElseThrow(() -> missingAttributeError(configBlock, join(".", parents), "host"));
+                    .orElseThrow(() -> missingAttributeError(configBlock, join(".", fullName), "host"));
 
             return createHostProxyHandler(context, hostAndPort, poolSettings, tlsSettings, responseTimeoutMillis, metricPrefix);
         }

components/proxy/src/main/java/com/hotels/styx/routing/handlers/HttpInterceptorPipeline.java

@@ -87,17 +87,17 @@ public CompletableFuture<Void> stop() {
     public static class Factory implements RoutingObjectFactory {
 
         @Override
-        public RoutingObject build(List<String> parents, Context context, RoutingObjectDefinition configBlock) {
+        public RoutingObject build(List<String> fullName, Context context, RoutingObjectDefinition configBlock) {
             JsonNode pipeline = configBlock.config().get("pipeline");
-            List<HttpInterceptor> interceptors = getHttpInterceptors(append(parents, "pipeline"), toMap(context.plugins()), context.interceptorFactories(), pipeline);
+            List<HttpInterceptor> interceptors = getHttpInterceptors(append(fullName, "pipeline"), toMap(context.plugins()), context.interceptorFactories(), pipeline);
 
             JsonNode handlerConfig = new JsonNodeConfig(configBlock.config())
                     .get("handler", JsonNode.class)
-                    .orElseThrow(() -> missingAttributeError(configBlock, join(".", parents), "handler"));
+                    .orElseThrow(() -> missingAttributeError(configBlock, join(".", fullName), "handler"));
 
             return new HttpInterceptorPipeline(
                     interceptors,
-                    Builtins.build(append(parents, "handler"), context, toRoutingConfigNode(handlerConfig)),
+                    Builtins.build(append(fullName, "handler"), context, toRoutingConfigNode(handlerConfig)),
                     context.requestTracking());
         }
 

components/proxy/src/main/java/com/hotels/styx/routing/handlers/PathPrefixRouter.java

@@ -92,10 +92,10 @@ public Optional<RoutingObject> route(LiveHttpRequest request) {
     public static class Factory implements RoutingObjectFactory {
 
         @Override
-        public RoutingObject build(List<String> parents, Context context, RoutingObjectDefinition configBlock) {
+        public RoutingObject build(List<String> fullName, Context context, RoutingObjectDefinition configBlock) {
             PathPrefixRouterConfig config = new JsonNodeConfig(configBlock.config()).as(PathPrefixRouterConfig.class);
             if (config.routes == null) {
-                throw missingAttributeError(configBlock, join(".", parents), "routes");
+                throw missingAttributeError(configBlock, join(".", fullName), "routes");
             }
 
             PathPrefixRouter pathPrefixRouter = new PathPrefixRouter(

components/proxy/src/main/java/com/hotels/styx/routing/handlers/ProxyToBackend.java

@@ -132,8 +132,8 @@ static RoutingObject build(List<String> parents, Context context, RoutingObjectD
         }
 
         @Override
-        public RoutingObject build(List<String> parents, Context context, RoutingObjectDefinition configBlock) {
-            return build(parents, context, configBlock, new StyxBackendServiceClientFactory(context.environment()));
+        public RoutingObject build(List<String> fullName, Context context, RoutingObjectDefinition configBlock) {
+            return build(fullName, context, configBlock, new StyxBackendServiceClientFactory(context.environment()));
         }
 
     }

components/proxy/src/main/java/com/hotels/styx/routing/handlers/StaticResponseHandler.java

@@ -77,7 +77,7 @@ public StaticResponseConfig(@JsonProperty("status") int status,
      * Builds a static response handler from Yaml configuration.
      */
     public static class Factory implements RoutingObjectFactory {
-        public RoutingObject build(List<String> parents, Context context, RoutingObjectDefinition configBlock) {
+        public RoutingObject build(List<String> fullName, Context context, RoutingObjectDefinition configBlock) {
             requireNonNull(configBlock.config());
 
             StaticResponseConfig config = new JsonNodeConfig(configBlock.config())

components/proxy/src/main/java/com/hotels/styx/startup/StyxServerComponents.java

@@ -32,7 +32,7 @@
 import com.hotels.styx.client.netty.eventloop.PlatformAwareClientEventLoopGroupFactory;
 import com.hotels.styx.infrastructure.configuration.yaml.JsonNodeConfig;
 import com.hotels.styx.proxy.plugin.NamedPlugin;
-import com.hotels.styx.routing.RoutingObjectDecorator;
+import com.hotels.styx.routing.RoutingMetadataDecorator;
 import com.hotels.styx.routing.RoutingObjectRecord;
 import com.hotels.styx.routing.config.Builtins;
 import com.hotels.styx.routing.config.RoutingObjectFactory;
@@ -109,7 +109,7 @@ private StyxServerComponents(Builder builder) {
                 .map(StyxServerComponents::readHttpHandlers)
                 .orElse(ImmutableMap.of())
                 .forEach((name, record) -> {
-                    RoutingObjectDecorator adapter = new RoutingObjectDecorator(Builtins.build(ImmutableList.of(name), routingObjectContext, record));
+                    RoutingMetadataDecorator adapter = new RoutingMetadataDecorator(Builtins.build(ImmutableList.of(name), routingObjectContext, record));
                     routeObjectStore.insert(name, new RoutingObjectRecord(record.type(), ImmutableSet.copyOf(record.tags()), record.config(), adapter))
                             .ifPresent(previous -> previous.getRoutingObject().stop());
                 });

components/proxy/src/main/kotlin/com/hotels/styx/routing/RoutingObjectRecord.kt

@@ -18,18 +18,18 @@ package com.hotels.styx.routing
 import com.fasterxml.jackson.databind.JsonNode
 
 /**
- * Holds routing object and its associated metadata.
+ * A routing object and its associated configuration metadata.
  */
 internal data class RoutingObjectRecord(
         val type: String,
         val tags: Set<String>,
         val config: JsonNode,
-        val routingObject: RoutingObjectDecorator) {
+        val routingObject: RoutingMetadataDecorator) {
     companion object {
         fun create(type: String, tags: Set<String>, config: JsonNode, routingObject: RoutingObject) = RoutingObjectRecord(
                 type,
                 tags,
                 config,
-                RoutingObjectDecorator(routingObject))
+                RoutingMetadataDecorator(routingObject))
     }
 }

components/proxy/src/main/kotlin/com/hotels/styx/routing/handlers/LoadBalancingGroup.kt

@@ -58,7 +58,7 @@ import java.util.concurrent.atomic.AtomicReference
  */
 internal class LoadBalancingGroup(val client: StyxBackendServiceClient, val changeWatcher: Disposable) : RoutingObject {
 
-    override fun handle(request: LiveHttpRequest?, context: HttpInterceptor.Context?) = Eventual(client.sendRequest(request))
+    override fun handle(request: LiveHttpRequest, context: HttpInterceptor.Context) = Eventual(client.sendRequest(request))
 
     override fun stop(): CompletableFuture<Void> {
         changeWatcher.dispose()
@@ -80,9 +80,9 @@ internal class LoadBalancingGroup(val client: StyxBackendServiceClient, val chan
     }
 
     class Factory : RoutingObjectFactory {
-        override fun build(parents: List<String>, context: RoutingObjectFactory.Context, configBlock: RoutingObjectDefinition): RoutingObject {
+        override fun build(fullName: List<String>, context: RoutingObjectFactory.Context, configBlock: RoutingObjectDefinition): RoutingObject {
 
-            val appId = parents.last()
+            val appId = fullName.last()
             val config = JsonNodeConfig(configBlock.config()).`as`(Config::class.java)
 
             val routeDb = context.routeDb()