Merge pull request #2764 from yahoo/gjoranv/use-builder-ctor-for-default-node

Use builder to instantiate default node.

2 files changed, 17 insertions, 5 deletions

diff --git a/config-lib/src/main/java/com/yahoo/config/InnerNodeVector.java b/config-lib/src/main/java/com/yahoo/config/InnerNodeVector.java
index eec2d3cd500..14c72ee8b14 100644
--- a/config-lib/src/main/java/com/yahoo/config/InnerNodeVector.java
+++ b/config-lib/src/main/java/com/yahoo/config/InnerNodeVector.java
@@ -3,6 +3,7 @@ package com.yahoo.config;
 
 import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationTargetException;
+import java.util.Arrays;
 import java.util.List;
 
 /**
@@ -36,13 +37,24 @@ public class InnerNodeVector<NODE extends InnerNode> extends NodeVector<NODE> {
     /**
      * Creates a new Node by creating a new instance with the 0-argument constructor
      */
-    // TODO: remove when the library uses reflection via builders
+    // TODO: remove, only used for NodeVector.setSize which only seems to be used by unit tests.
     @SuppressWarnings("unchecked")
     protected NODE createNew() {
         try {
-            Constructor<? extends InnerNode> ctor  = defaultNode.getClass().getDeclaredConstructor();
-            ctor.setAccessible(true);
-            return (NODE) ctor.newInstance();
+            Class<? extends InnerNode> nodeClass = defaultNode.getClass();
+            Class<?> builderClass = Arrays.stream(nodeClass.getClasses())
+                    .filter(klass -> klass.getSimpleName().equals("Builder"))
+                    .findFirst()
+                    .orElseThrow(() -> new ConfigurationRuntimeException("Could not find builder class for " + nodeClass.getName()));
+
+            Constructor<?> builderCtor = builderClass.getConstructor();
+            Object builderInstance = builderCtor.newInstance();
+            if (! (builderInstance instanceof ConfigBuilder))
+                throw new ConfigurationRuntimeException("Builder is not a ConfigBuilder, has class: " + builderInstance.getClass().getName());
+
+            Constructor<? extends InnerNode> nodeCtor = nodeClass.getDeclaredConstructor(builderClass, boolean.class);
+            nodeCtor.setAccessible(true);
+            return (NODE) nodeCtor.newInstance(builderInstance, false);
         } catch (InvocationTargetException | IllegalAccessException | InstantiationException | NoSuchMethodException e) {
             throw new ConfigurationRuntimeException(e);
         }
diff --git a/config-lib/src/main/java/com/yahoo/config/NodeVector.java b/config-lib/src/main/java/com/yahoo/config/NodeVector.java
index 8ce5689937e..5279db65b85 100644
--- a/config-lib/src/main/java/com/yahoo/config/NodeVector.java
+++ b/config-lib/src/main/java/com/yahoo/config/NodeVector.java
@@ -34,7 +34,7 @@ public abstract class NodeVector<NODE> implements java.util.List<NODE> {
      *
      * @param n the new size of this NodeVector
      */
-    // TODO: remove when the library uses reflection via builders, and resizing won't be necessary
+    // TODO: remove, only used by unit tests
     public void setSize(int n) {
         while (size() > n) vector.remove(n);
         while (size() < n) vector.add(createNew());