| // Copyright (C) 2009 The Android Open Source Project |
| // |
| // 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.gerrit.server.config; |
| |
| import com.google.inject.AbstractModule; |
| import com.google.inject.Key; |
| import com.google.inject.assistedinject.FactoryProvider; |
| |
| import java.lang.reflect.Method; |
| import java.lang.reflect.Modifier; |
| |
| public abstract class FactoryModule extends AbstractModule { |
| /** |
| * Register an assisted injection factory. |
| * <p> |
| * This function provides an automatic way to define a factory that creates a |
| * concrete type through assisted injection. For example to configure the |
| * following assisted injection case: |
| * |
| * <pre> |
| * public class Foo { |
| * public interface Factory { |
| * Foo create(int a); |
| * } |
| * @Inject |
| * Foo(Logger log, @Assisted int a) {...} |
| * } |
| * </pre> |
| * |
| * Just pass {@code Foo.Factory.class} to this method. The factory will be |
| * generated to return its one return type as declared in the creation method. |
| * |
| * @param <F> |
| * @param factory interface which specifies the bean factory method. |
| */ |
| protected <F> void factory(final Class<F> factory) { |
| factory(Key.get(factory), factory); |
| } |
| |
| /** |
| * Register an assisted injection factory. |
| * <p> |
| * This function provides an automatic way to define a factory that creates a |
| * concrete type through assited injection. For example to configure the |
| * following assisted injection case: |
| * |
| * <pre> |
| * public class Foo { |
| * public interface Factory { |
| * Foo create(int a); |
| * } |
| * @Inject |
| * Foo(Logger log, @Assisted int a) {...} |
| * } |
| * </pre> |
| * |
| * Just pass {@code Foo.Factory.class} to this method. The factory will be |
| * generated to return its one return type as declared in the creation method. |
| * |
| * @param <F> |
| * @param key key to bind with in Guice bindings. |
| * @param factory interface which specifies the bean factory method. |
| */ |
| protected <F> void factory(final Key<F> key, final Class<F> factory) { |
| final Method[] methods = factory.getDeclaredMethods(); |
| switch (methods.length) { |
| case 1: { |
| final Class<?> result = methods[0].getReturnType(); |
| if (isAbstract(result)) { |
| addError("Factory " + factory.getName() + " returns abstract result."); |
| } else { |
| bind(key).toProvider(FactoryProvider.newFactory(factory, result)); |
| } |
| break; |
| } |
| |
| case 0: |
| addError("Factory " + factory.getName() + " has no create method."); |
| break; |
| |
| default: |
| addError("Factory " + factory.getName() |
| + " has more than one create method."); |
| break; |
| } |
| } |
| |
| private static boolean isAbstract(final Class<?> result) { |
| return result.isInterface() |
| || (result.getModifiers() & Modifier.ABSTRACT) == Modifier.ABSTRACT; |
| } |
| } |