mv com/google/domain/registry google/registry

This change renames directories in preparation for the great package
rename. The repository is now in a broken state because the code
itself hasn't been updated. However this should ensure that git
correctly preserves history for each file.

java/google/registry/request/Router.java

@@ -0,0 +1,107 @@
+// Copyright 2016 The Domain Registry Authors. All Rights Reserved.
+//
+// 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
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// 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.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.domain.registry.request;
+
+import com.google.common.base.Function;
+import com.google.common.base.Optional;
+import com.google.common.base.Throwables;
+import com.google.common.collect.ImmutableSortedMap;
+import com.google.common.collect.Ordering;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.Map;
+import java.util.TreeMap;
+
+/**
+ * Path prefix request router for Domain Registry.
+ *
+ * <p>See the documentation of {@link RequestHandler} for more information.
+ *
+ * <h3>Implementation Details</h3>
+ *
+ * <p>Request routing is O(logn) because {@link ImmutableSortedMap} performs a binary search over a
+ * contiguous array, which makes it faster than a {@link TreeMap}. However a prefix trie search in
+ * generated code would be the ideal approach.
+ */
+final class Router {
+
+  static Router create(Iterable<Method> componentMethods) {
+    return new Router(extractRoutesFromComponent(componentMethods));
+  }
+
+  private final ImmutableSortedMap<String, Route> routes;
+
+  private Router(ImmutableSortedMap<String, Route> routes) {
+    this.routes = routes;
+  }
+
+  /** Returns the appropriate action route for a request. */
+  Optional<Route> route(String path) {
+    Map.Entry<String, Route> floor = routes.floorEntry(path);
+    if (floor != null) {
+      if (floor.getValue().action().isPrefix()
+          ? path.startsWith(floor.getKey())
+          : path.equals(floor.getKey())) {
+        return Optional.of(floor.getValue());
+      }
+    }
+    return Optional.absent();
+  }
+
+  private static
+      ImmutableSortedMap<String, Route> extractRoutesFromComponent(Iterable<Method> methods) {
+    ImmutableSortedMap.Builder<String, Route> routes =
+        new ImmutableSortedMap.Builder<>(Ordering.natural());
+    for (Method method : methods) {
+      if (!isDaggerInstantiatorOfType(Runnable.class, method)) {
+        continue;
+      }
+      Action action = method.getReturnType().getAnnotation(Action.class);
+      if (action == null) {
+        continue;
+      }
+      @SuppressWarnings("unchecked")  // Safe due to previous checks.
+      Route route =
+          Route.create(action, (Function<Object, Runnable>) newInstantiator(method));
+      routes.put(action.path(), route);
+    }
+    return routes.build();
+  }
+
+  private static boolean isDaggerInstantiatorOfType(Class<?> type, Method method) {
+    return method.getParameterTypes().length == 0
+        && type.isAssignableFrom(method.getReturnType());
+  }
+
+  private static Function<Object, ?> newInstantiator(final Method method) {
+    return new Function<Object, Object>() {
+      @Override
+      public Object apply(Object component) {
+        try {
+          return method.invoke(component);
+        } catch (IllegalAccessException e) {
+          throw new RuntimeException(
+              "Error reflectively accessing component's @Action factory method", e);
+        } catch (InvocationTargetException e) {
+          // This means an exception was thrown during the injection process while instantiating
+          // the @Action class; we should propagate that underlying exception.
+          Throwables.propagateIfPossible(e.getCause());
+          throw new AssertionError(
+              "Component's @Action factory method somehow threw checked exception", e);
+        }
+      }};
+  }
+}