move some stuff from ConfigImpl to a new class Loader

This is just to make ConfigImpl less of a random jumble.

src/main/java/com/typesafe/config/impl/ConfigImpl.java

@@ -1,20 +1,13 @@
 package com.typesafe.config.impl;
 
-import java.io.IOException;
-import java.io.InputStream;
-import java.net.URL;
 import java.util.ArrayList;
-import java.util.Collections;
-import java.util.Enumeration;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.Properties;
 
 import com.typesafe.config.ConfigConfig;
 import com.typesafe.config.ConfigException;
 import com.typesafe.config.ConfigObject;
-import com.typesafe.config.ConfigOrigin;
 
 /** This is public but is only supposed to be used by the "config" package */
 public class ConfigImpl {
@@ -32,10 +25,7 @@ public class ConfigImpl {
         if (system != null)
             stack.add(system);
 
-        // now try to load a resource for each extension
+        stack.add(Loader.load(configConfig.rootPath()));
-        addResource(configConfig.rootPath() + ".conf", stack);
-        addResource(configConfig.rootPath() + ".json", stack);
-        addResource(configConfig.rootPath() + ".properties", stack);
 
         ConfigTransformer transformer = withExtraTransformer(null);
 
@@ -49,14 +39,6 @@ public class ConfigImpl {
         return (AbstractConfigObject) resolved;
     }
 
-    private static void addResource(String name,
-            List<AbstractConfigObject> stack) {
-        URL url = ConfigImpl.class.getResource("/" + name);
-        if (url != null) {
-            stack.add(loadURL(url));
-        }
-    }
-
     static ConfigObject getEnvironmentAsConfig() {
         // This should not need to create a new config object
         // as long as the transformer is just the default transformer.
@@ -71,39 +53,6 @@ public class ConfigImpl {
                 withExtraTransformer(null));
     }
 
-    static AbstractConfigObject loadURL(URL url) {
-        if (url.getPath().endsWith(".properties")) {
-            ConfigOrigin origin = new SimpleConfigOrigin(url.toExternalForm());
-            Properties props = new Properties();
-            InputStream stream = null;
-            try {
-                stream = url.openStream();
-                props.load(stream);
-            } catch (IOException e) {
-                throw new ConfigException.IO(origin, "failed to open url", e);
-            } finally {
-                if (stream != null) {
-                    try {
-                        stream.close();
-                    } catch (IOException e) {
-                    }
-                }
-            }
-            return fromProperties(url.toExternalForm(), props);
-        } else {
-            return forceParsedToObject(Parser.parse(url));
-        }
-    }
-
-    static AbstractConfigObject forceParsedToObject(AbstractConfigValue value) {
-        if (value instanceof AbstractConfigObject) {
-            return (AbstractConfigObject) value;
-        } else {
-            throw new ConfigException.WrongType(value.origin(), "",
-                    "object at file root", value.valueType().name());
-        }
-    }
-
     private static ConfigTransformer withExtraTransformer(
             ConfigTransformer extraTransformer) {
         // idea is to avoid creating a new, unique transformer if there's no
@@ -120,7 +69,7 @@ public class ConfigImpl {
 
     private static ConfigTransformer defaultTransformer = null;
 
-    private synchronized static ConfigTransformer defaultConfigTransformer() {
+    synchronized static ConfigTransformer defaultConfigTransformer() {
         if (defaultTransformer == null) {
             defaultTransformer = new DefaultTransformer();
         }
@@ -137,8 +86,7 @@ public class ConfigImpl {
     }
 
     private static AbstractConfigObject loadSystemProperties() {
-        return fromProperties("system property", System.getProperties());
+        return Loader.fromProperties("system property", System.getProperties());
-
     }
 
     // this is a hack to let us set system props in the test suite
@@ -146,75 +94,6 @@ public class ConfigImpl {
         systemProperties = null;
     }
 
-    private static AbstractConfigObject fromProperties(String originPrefix,
-            Properties props) {
-        Map<String, Map<String, AbstractConfigValue>> scopes = new HashMap<String, Map<String, AbstractConfigValue>>();
-        Enumeration<?> i = props.propertyNames();
-        while (i.hasMoreElements()) {
-            Object o = i.nextElement();
-            if (o instanceof String) {
-                try {
-                    String path = (String) o;
-                    String last = ConfigUtil.lastElement(path);
-                    String exceptLast = ConfigUtil.exceptLastElement(path);
-                    if (exceptLast == null)
-                        exceptLast = "";
-                    Map<String, AbstractConfigValue> scope = scopes
-                            .get(exceptLast);
-                    if (scope == null) {
-                        scope = new HashMap<String, AbstractConfigValue>();
-                        scopes.put(exceptLast, scope);
-                    }
-                    String value = props.getProperty(path);
-                    scope.put(last, new ConfigString(new SimpleConfigOrigin(
-                            originPrefix + " " + path), value));
-                } catch (ConfigException.BadPath e) {
-                    // just skip this one (log it?)
-                }
-            }
-        }
-
-        // pull out the list of objects that go inside other objects
-        List<String> childPaths = new ArrayList<String>();
-        for (String path : scopes.keySet()) {
-            if (path != "")
-                childPaths.add(path);
-        }
-
-        // put everything in its parent, ensuring all parents exist
-        for (String path : childPaths) {
-            String parentPath = ConfigUtil.exceptLastElement(path);
-            if (parentPath == null)
-                parentPath = "";
-
-            Map<String, AbstractConfigValue> parent = scopes.get(parentPath);
-            if (parent == null) {
-                parent = new HashMap<String, AbstractConfigValue>();
-                scopes.put(parentPath, parent);
-            }
-            // NOTE: we are evil and cheating, we mutate the map we
-            // provide to SimpleConfigObject, which is not allowed by
-            // its contract, but since we know nobody has a ref to this
-            // SimpleConfigObject yet we can get away with it.
-            AbstractConfigObject o = new SimpleConfigObject(
-                    new SimpleConfigOrigin(
-                    originPrefix + " " + path), null, scopes.get(path));
-            String basename = ConfigUtil.lastElement(path);
-            parent.put(basename, o);
-        }
-
-        Map<String, AbstractConfigValue> root = scopes.get("");
-        if (root == null) {
-            // this would happen only if you had no properties at all
-            // in "props"
-            root = Collections.<String, AbstractConfigValue> emptyMap();
-        }
-
-        // return root config object
-        return new SimpleConfigObject(new SimpleConfigOrigin(originPrefix),
-                null, root);
-    }
-
     private static AbstractConfigObject envVariables = null;
 
     synchronized static AbstractConfigObject envVariablesConfig() {

src/main/java/com/typesafe/config/impl/Loader.java

@@ -0,0 +1,150 @@
+package com.typesafe.config.impl;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Enumeration;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Properties;
+
+import com.typesafe.config.ConfigException;
+import com.typesafe.config.ConfigOrigin;
+
+final class Loader {
+    static AbstractConfigObject load(String name) {
+        List<AbstractConfigObject> stack = new ArrayList<AbstractConfigObject>();
+
+        // if name has an extension, only use that; otherwise merge all three
+        if (name.endsWith(".conf") || name.endsWith(".json")
+                || name.endsWith(".properties")) {
+            addResource(name, stack);
+        } else {
+            // .conf wins over .json wins over .properties;
+            // arbitrary, but deterministic
+            addResource(name + ".conf", stack);
+            addResource(name + ".json", stack);
+            addResource(name + ".properties", stack);
+        }
+
+        AbstractConfigObject merged = AbstractConfigObject.merge(
+                new SimpleConfigOrigin("config for " + name), stack,
+                ConfigImpl.defaultConfigTransformer());
+
+        return merged;
+    }
+
+    private static void addResource(String name,
+            List<AbstractConfigObject> stack) {
+        URL url = ConfigImpl.class.getResource("/" + name);
+        if (url != null) {
+            stack.add(loadURL(url));
+        }
+    }
+
+    private static AbstractConfigObject loadURL(URL url) {
+        if (url.getPath().endsWith(".properties")) {
+            ConfigOrigin origin = new SimpleConfigOrigin(url.toExternalForm());
+            Properties props = new Properties();
+            InputStream stream = null;
+            try {
+                stream = url.openStream();
+                props.load(stream);
+            } catch (IOException e) {
+                throw new ConfigException.IO(origin, "failed to open url", e);
+            } finally {
+                if (stream != null) {
+                    try {
+                        stream.close();
+                    } catch (IOException e) {
+                    }
+                }
+            }
+            return fromProperties(url.toExternalForm(), props);
+        } else {
+            return forceParsedToObject(Parser.parse(url));
+        }
+    }
+
+    private static AbstractConfigObject forceParsedToObject(
+            AbstractConfigValue value) {
+        if (value instanceof AbstractConfigObject) {
+            return (AbstractConfigObject) value;
+        } else {
+            throw new ConfigException.WrongType(value.origin(), "",
+                    "object at file root", value.valueType().name());
+        }
+    }
+
+    static AbstractConfigObject fromProperties(String originPrefix,
+            Properties props) {
+        Map<String, Map<String, AbstractConfigValue>> scopes = new HashMap<String, Map<String, AbstractConfigValue>>();
+        Enumeration<?> i = props.propertyNames();
+        while (i.hasMoreElements()) {
+            Object o = i.nextElement();
+            if (o instanceof String) {
+                try {
+                    String path = (String) o;
+                    String last = ConfigUtil.lastElement(path);
+                    String exceptLast = ConfigUtil.exceptLastElement(path);
+                    if (exceptLast == null)
+                        exceptLast = "";
+                    Map<String, AbstractConfigValue> scope = scopes
+                            .get(exceptLast);
+                    if (scope == null) {
+                        scope = new HashMap<String, AbstractConfigValue>();
+                        scopes.put(exceptLast, scope);
+                    }
+                    String value = props.getProperty(path);
+                    scope.put(last, new ConfigString(new SimpleConfigOrigin(
+                            originPrefix + " " + path), value));
+                } catch (ConfigException.BadPath e) {
+                    // just skip this one (log it?)
+                }
+            }
+        }
+
+        // pull out the list of objects that go inside other objects
+        List<String> childPaths = new ArrayList<String>();
+        for (String path : scopes.keySet()) {
+            if (path != "")
+                childPaths.add(path);
+        }
+
+        // put everything in its parent, ensuring all parents exist
+        for (String path : childPaths) {
+            String parentPath = ConfigUtil.exceptLastElement(path);
+            if (parentPath == null)
+                parentPath = "";
+
+            Map<String, AbstractConfigValue> parent = scopes.get(parentPath);
+            if (parent == null) {
+                parent = new HashMap<String, AbstractConfigValue>();
+                scopes.put(parentPath, parent);
+            }
+            // NOTE: we are evil and cheating, we mutate the map we
+            // provide to SimpleConfigObject, which is not allowed by
+            // its contract, but since we know nobody has a ref to this
+            // SimpleConfigObject yet we can get away with it.
+            AbstractConfigObject o = new SimpleConfigObject(
+                    new SimpleConfigOrigin(originPrefix + " " + path), null,
+                    scopes.get(path));
+            String basename = ConfigUtil.lastElement(path);
+            parent.put(basename, o);
+        }
+
+        Map<String, AbstractConfigValue> root = scopes.get("");
+        if (root == null) {
+            // this would happen only if you had no properties at all
+            // in "props"
+            root = Collections.<String, AbstractConfigValue> emptyMap();
+        }
+
+        // return root config object
+        return new SimpleConfigObject(new SimpleConfigOrigin(originPrefix),
+                null, root);
+    }
+}