Java tutorial
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We also recommend that a * file or class name and description of purpose be included on the * same "printed page" as the copyright notice for easier * identification within third-party archives. * * Copyright 2014 Edgar Espina * * 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 org.jooby.guava; import static java.util.Objects.requireNonNull; import java.lang.reflect.ParameterizedType; import java.lang.reflect.Type; import java.util.ArrayList; import java.util.List; import java.util.Map; import java.util.stream.Collectors; import org.jooby.Env; import org.jooby.Jooby; import org.jooby.Session; import com.google.common.cache.Cache; import com.google.common.cache.CacheBuilder; import com.google.common.cache.CacheBuilderSpec; import com.google.common.cache.LoadingCache; import com.google.inject.Binder; import com.google.inject.Key; import com.google.inject.TypeLiteral; import com.google.inject.name.Names; import com.google.inject.util.Types; import com.typesafe.config.Config; import com.typesafe.config.ConfigFactory; import com.typesafe.config.ConfigValueFactory; /** * <h1>guava-cache</h1> * <p> * {@link Cache} services from <a href="https://github.com/google/guava">Guava</a> * </p> * * <h2>usage</h2> * * <p> * App.java: * </p> * <pre> * { * use(GuavaCache.newCache()); * * get("/", req {@literal ->} { * Cache cache = req.require(Cache.class); * // do with cache... * }); * } * </pre> * * <h2>options</h2> * * <h3>cache configuration</h3> * <p> * A default cache will be created, if you need to control the number of entries, expire policy, * etc... set the <code>guava.cache</code> property in <code>application.conf</code>, like: * </p> * * <pre> * guava.cache { * maximumSize = 10 * concurrencyLevel = 2 * } * </pre> * * or via {@link CacheBuilderSpec} syntax: * * <pre> * guava.cache = "maximumSize=10,concurrencyLevel=2" * </pre> * * <h3>multiple caches</h3> * <p> * Just add entries to: <code>guava.</code>, like: * </p> * * <pre> * # default cache (don't need a name on require calls) * guava.cache = "maximumSize=10" * * guava.cache1 = "maximumSize=1" * * guava.cacheX = "maximumSize=100" * </pre> * * <pre> * { * get("/", req {@literal ->} { * Cache defcache = req.require(Cache.class); * * Cache cache1 = req.require("cache1", Cache.class); * * Cache cacheX = req.require("cacheX", Cache.class); * }); * } * </pre> * * <h3>type-safe caches</h3> * <p> * Type safe caches are provided by calling and creating a new {@link GuavaCache} subclass: * </p> * * <pre> * { * // please notes the {} at the line of the next line * use(new GuavaCache<Integer, String>() {}); * } * </pre> * * <p> * Later, you can inject this cache in a type-safe manner: * </p> * * <pre> * @Inject * public MyService(Cache<Integer, String> cache) { * ... * } * </pre> * * <h2>session store</h2> * <p> * This module comes with a {@link Session.Store} implementation. In order to use it you need to * define a cache named <code>session</code> in your <code>application.conf</code> file: * </p> * * <pre> * guava.session = "maximumSize=10" * </pre> * * And set the {@link GuavaSessionStore}: * * <pre> * { * session(GuavaSessionStore.class); * } * </pre> * * You can access to the ```session``` via name: * * <pre> * { * get("/", req {@literal} { * Cache cache = req.require("session", Cache.class); * }); * } * </pre> * * @author edgar * @since 0.15.0 * @param <K> Cache key. * @param <V> Cache value. * @see GuavaSessionStore */ public abstract class GuavaCache<K, V> implements Jooby.Module { public interface Callback<K, V, C extends Cache<K, V>> { C apply(String name, CacheBuilder<K, V> builder); } private static final String DEF = "guava"; private Callback<K, V, Cache<K, V>> callback = (n, b) -> b.build(); private final String name; /** * Creates a new {@link GuavaCache} using the provided namespace. * * @param name Cache namespace. */ public GuavaCache(final String name) { this.name = name; } /** * Creates a new {@link GuavaCache} using <code>guava</code> as cache namespace. */ public GuavaCache() { this(DEF); } /** * Creates a new {@link GuavaCache} with {@link String} and {@link Object} types as key/value. * * @return A new {@link GuavaCache}. */ public static final GuavaCache<String, Object> newCache() { return new GuavaCache<String, Object>() { }; } /** * Configure a cache builder and creates a new {@link Cache}. * * @param configurer Configurer callback. * @return This instance. */ public GuavaCache<K, V> doWith(final Callback<K, V, Cache<K, V>> configurer) { this.callback = requireNonNull(configurer, "Configurer callback is required."); return this; } @SuppressWarnings({ "unchecked", "rawtypes" }) @Override public void configure(final Env env, final Config conf, final Binder binder) { Config gconf = conf.hasPath(name) ? conf : ConfigFactory.empty(); gconf = gconf .withFallback(ConfigFactory.empty().withValue("guava.cache", ConfigValueFactory.fromAnyRef(""))); gconf.getObject(name).unwrapped().forEach((name, spec) -> { CacheBuilder<K, V> cb = (CacheBuilder<K, V>) CacheBuilder.from(toSpec(spec)); Cache<K, V> cache = callback.apply(name, cb); List<TypeLiteral> types = cacheType(name, cache, getClass().getGenericSuperclass()); types.forEach(type -> { binder.bind(Key.get(type, Names.named(name))).toInstance(cache); if (name.equals("cache")) { // unnamed cache for default cache binder.bind(type).toInstance(cache); // raw type for default cache binder.bind(type.getRawType()).toInstance(cache); } if (name.equals("session")) { binder.bind(Key.get(type, Names.named(name))).toInstance(cache); binder.bind(Key.get(type.getRawType(), Names.named(name))).toInstance(cache); } }); }); } @SuppressWarnings("rawtypes") private static List<TypeLiteral> cacheType(final String name, final Cache cache, final Type superclass) { Class[] ctypes = cache instanceof LoadingCache ? new Class[] { LoadingCache.class, Cache.class } : new Class[] { Cache.class }; List<TypeLiteral> result = new ArrayList<>(ctypes.length); for (Class ctype : ctypes) { if (name.equals("session")) { result.add(TypeLiteral.get(Types.newParameterizedType(ctype, String.class, Session.class))); } else { result.add(TypeLiteral.get(Types.newParameterizedType(ctype, types(superclass)))); } } return result; } @SuppressWarnings("unchecked") private String toSpec(final Object spec) { if (spec instanceof Map) { Map<String, Object> m = (Map<String, Object>) spec; return m.entrySet().stream().map(e -> e.getKey() + "=" + e.getValue()).collect(Collectors.joining(",")); } return spec.toString(); } private static Type[] types(final Type superclass) { Type key = String.class; Type value = Object.class; if (superclass instanceof ParameterizedType) { ParameterizedType parameterized = (ParameterizedType) superclass; Type[] args = parameterized.getActualTypeArguments(); key = args[0]; value = args[1]; } return new Type[] { key, value }; } }