Copying logic from old classes

components/proxy/src/main/java/com/hotels/styx/infrastructure/configuration/ExtensibleConfiguration.java

@@ -1,12 +1,12 @@
 /**
  * Copyright (C) 2013-2018 Expedia Inc.
- *
+ * <p>
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- *
+ * <p>
  * http://www.apache.org/licenses/LICENSE-2.0
- *
+ * <p>
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -15,9 +15,13 @@
  */
 package com.hotels.styx.infrastructure.configuration;
 
+import com.google.common.collect.ImmutableList;
 import com.hotels.styx.api.configuration.Configuration;
+import com.hotels.styx.infrastructure.configuration.yaml.PlaceholderResolver.UnresolvedPlaceholder;
 
+import java.util.Collection;
 import java.util.Map;
+import java.util.Objects;
 
 /**
  * Extensible configuration, interface is agnostic to how it is stored in memory.
@@ -29,7 +33,23 @@ public interface ExtensibleConfiguration<C extends ExtensibleConfiguration<C>> e
 
     C withOverrides(Map<String, String> overrides);
 
-    int unresolvedPlaceholderCount();
+    PlaceholderResolutionResult<C> resolvePlaceholders();
+
+    class PlaceholderResolutionResult<C extends ExtensibleConfiguration<C>> {
+        private final C resolvedConfiguration;
+        private final Collection<UnresolvedPlaceholder> unresolvedPlaceholders;
+
+        public PlaceholderResolutionResult(C resolvedConfiguration, Collection<UnresolvedPlaceholder> unresolvedPlaceholders) {
+            this.resolvedConfiguration = Objects.requireNonNull(resolvedConfiguration);
+            this.unresolvedPlaceholders = ImmutableList.copyOf(unresolvedPlaceholders);
+        }
+
+        public C resolvedConfiguration() {
+            return resolvedConfiguration;
+        }
 
-    C resolvePlaceholders();
+        public Collection<UnresolvedPlaceholder> unresolvedPlaceholders() {
+            return unresolvedPlaceholders;
+        }
+    }
 }

components/proxy/src/main/java/com/hotels/styx/infrastructure/configuration/Parser.java

@@ -16,6 +16,7 @@
 package com.hotels.styx.infrastructure.configuration;
 
 import com.google.common.annotations.VisibleForTesting;
+import com.hotels.styx.infrastructure.configuration.ExtensibleConfiguration.PlaceholderResolutionResult;
 import com.hotels.styx.infrastructure.configuration.yaml.YamlConfig;
 
 import java.util.Map;
@@ -70,18 +71,13 @@ private C deserialise(ConfigurationProvider provider) {
     }
 
     private C resolvePlaceholders(C config) {
-        if (config.unresolvedPlaceholderCount() == 0) {
-            return config;
-        }
-
-        int previousUnresolvedPlaceholderCount;
+        PlaceholderResolutionResult<C> result = config.resolvePlaceholders();
 
-        do {
-            previousUnresolvedPlaceholderCount = config.unresolvedPlaceholderCount();
-            config = config.resolvePlaceholders();
-        } while (config.unresolvedPlaceholderCount() < previousUnresolvedPlaceholderCount);
+        if (!result.unresolvedPlaceholders().isEmpty()) {
+            throw new IllegalStateException("Unresolved placeholders: " + result.unresolvedPlaceholders());
+        }
 
-        return config;
+        return result.resolvedConfiguration();
     }
 
     private C parent(String includePath) {

components/proxy/src/main/java/com/hotels/styx/infrastructure/configuration/yaml/YamlConfiguration.java

@@ -5,41 +5,68 @@
 import com.fasterxml.jackson.databind.node.ObjectNode;
 import com.hotels.styx.api.configuration.ConversionException;
 import com.hotels.styx.infrastructure.configuration.ExtensibleConfiguration;
+import com.hotels.styx.infrastructure.configuration.yaml.PlaceholderResolver.UnresolvedPlaceholder;
 
 import java.io.IOException;
 import java.nio.file.Path;
 import java.nio.file.Paths;
+import java.util.Collection;
 import java.util.Map;
 import java.util.Optional;
 
 import static com.google.common.base.Throwables.propagate;
 import static com.hotels.styx.infrastructure.configuration.yaml.YamlConfigurationFormat.YAML_MAPPER;
+import static java.util.Collections.emptyMap;
 import static java.util.Objects.requireNonNull;
 
 /**
  *
  */
 public class YamlConfiguration implements ExtensibleConfiguration<YamlConfiguration> {
     private final JsonNode rootNode;
-    private final int unresolvedPlaceholders;
 
     public YamlConfiguration(JsonNode rootNode) {
         this.rootNode = requireNonNull(rootNode);
-        this.unresolvedPlaceholders = countUnresolvedPlaceholders();
     }
 
-    private YamlConfiguration(JsonNode rootNode, int unresolvedPlaceholders) {
-        this.rootNode = requireNonNull(rootNode);
-        this.unresolvedPlaceholders = unresolvedPlaceholders;
+    @Override
+    public YamlConfiguration withParent(YamlConfiguration parent) {
+        return new YamlConfiguration(merge(parent.rootNode.deepCopy(), rootNode));
     }
 
-    private static int countUnresolvedPlaceholders() {
-        return 0;
+    @Override
+    public YamlConfiguration withOverrides(Map<String, String> overrides) {
+        JsonNode newRootNode = rootNode.deepCopy();
+
+        applyExternalOverrides(newRootNode, overrides);
+
+        return new YamlConfiguration(newRootNode);
     }
 
     @Override
-    public YamlConfiguration withParent(YamlConfiguration parent) {
-        return new YamlConfiguration(merge(parent.rootNode.deepCopy(), rootNode));
+    public PlaceholderResolutionResult<YamlConfiguration> resolvePlaceholders() {
+        JsonNode newRootNode = rootNode.deepCopy();
+
+        Collection<UnresolvedPlaceholder> unresolvedPlaceholders = PlaceholderResolver.resolvePlaceholders(newRootNode, emptyMap());
+
+        return new PlaceholderResolutionResult<>(new YamlConfiguration(newRootNode), unresolvedPlaceholders);
+    }
+
+    @Override
+    public <T> Optional<T> get(String property, Class<T> tClass) {
+        return nodeAt(property)
+                .map(node -> {
+                    if (tClass == Path.class) {
+                        return (T) Paths.get(node.textValue());
+                    }
+
+                    return parseNodeToClass(node, tClass);
+                });
+    }
+
+    @Override
+    public <X> X as(Class<X> type) throws ConversionException {
+        return parseNodeToClass(rootNode, type);
     }
 
     private static JsonNode merge(JsonNode baseNode, JsonNode overrideNode) {
@@ -63,15 +90,6 @@ private static JsonNode merge(JsonNode baseNode, JsonNode overrideNode) {
         return baseNode;
     }
 
-    @Override
-    public YamlConfiguration withOverrides(Map<String, String> overrides) {
-        JsonNode newRootNode = rootNode.deepCopy();
-
-        applyExternalOverrides(newRootNode, overrides);
-
-        return new YamlConfiguration(newRootNode, unresolvedPlaceholders);
-    }
-
     private static void applyExternalOverrides(JsonNode rootNode, Map<String, String> overrides) {
         overrides.forEach((key, value) -> {
             NodePath nodePath = new NodePath(key);
@@ -80,37 +98,6 @@ private static void applyExternalOverrides(JsonNode rootNode, Map<String, String
         });
     }
 
-    @Override
-    public int unresolvedPlaceholderCount() {
-        return unresolvedPlaceholders;
-    }
-
-    @Override
-    public YamlConfiguration resolvePlaceholders() {
-        int stillUnresolved = 0;
-
-        JsonNode newRootNode = null;
-
-        return new YamlConfiguration(newRootNode, stillUnresolved);
-    }
-
-    @Override
-    public <T> Optional<T> get(String property, Class<T> tClass) {
-        return nodeAt(property)
-                .map(node -> {
-                    if (tClass == Path.class) {
-                        return (T) Paths.get(node.textValue());
-                    }
-
-                    return parseNodeToClass(node, tClass);
-                });
-    }
-
-    @Override
-    public <X> X as(Class<X> type) throws ConversionException {
-        return parseNodeToClass(rootNode, type);
-    }
-
     private Optional<JsonNode> nodeAt(String property) {
         NodePath nodePath = new NodePath(property);