| // Copyright (C) 2013 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.googlesource.gerrit.plugins.hooks.rtc.network; |
| |
| import java.io.IOException; |
| import java.util.Map; |
| import java.util.concurrent.ConcurrentHashMap; |
| |
| |
| public class CachableResourcesFactory { |
| |
| public final Map<Class<?>, InternalFactory<?>> factories; |
| private Transport transport; |
| |
| public CachableResourcesFactory(Transport transport) { |
| this.transport = transport; |
| this.factories = new ConcurrentHashMap<Class<?>, InternalFactory<?>>(); |
| } |
| |
| @SuppressWarnings("unchecked") |
| public <T> T get(String url, Class<T> clazz) throws IOException { |
| return (T) getFactory(clazz).get(url); |
| } |
| |
| @SuppressWarnings("unchecked") |
| private <T> InternalFactory<?> getFactory(Class<T> clazz) { |
| InternalFactory<?> factory = factories.get(clazz); |
| if (factory == null) { |
| factory = new InternalFactory(transport, clazz); |
| factories.put(clazz, factory); |
| } |
| return factory; |
| } |
| |
| private static class InternalFactory<T> { |
| |
| private final Transport transport; |
| private final Map<String, T> cache; |
| private Class<T> clazz; |
| |
| private InternalFactory(Transport transport, Class<T> clazz) { |
| this.transport = transport; |
| this.clazz = clazz; |
| this.cache = new ConcurrentHashMap<String, T>(); |
| } |
| |
| private T get(final String url) throws IOException { |
| T result = cache.get(url); |
| if (result == null) { |
| result = streamResourceFrom(url, clazz); |
| cache.put(url, result); |
| } |
| |
| return result; |
| } |
| |
| private T streamResourceFrom(final String url, final Class<T> clazz) throws IOException { |
| return transport.get(url+".json", clazz); |
| } |
| } |
| } |