| /* |
| * Copyright (C) 2007 Google Inc. |
| * |
| * 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.inject.util; |
| |
| import static com.google.common.base.Preconditions.checkNotNull; |
| |
| import java.util.Set; |
| |
| import com.google.inject.Inject; |
| import com.google.inject.Injector; |
| import com.google.inject.Provider; |
| import com.google.common.collect.ImmutableSet; |
| import com.google.common.collect.Sets; |
| import com.google.inject.spi.Dependency; |
| import com.google.inject.spi.InjectionPoint; |
| import com.google.inject.spi.ProviderWithDependencies; |
| |
| /** |
| * Static utility methods for creating and working with instances of |
| * {@link Provider}. |
| * |
| * @author Kevin Bourrillion (kevinb9n@gmail.com) |
| * @since 2.0 |
| */ |
| public final class Providers { |
| |
| private Providers() {} |
| |
| /** |
| * Returns a provider which always provides {@code instance}. This should not |
| * be necessary to use in your application, but is helpful for several types |
| * of unit tests. |
| * |
| * @param instance the instance that should always be provided. This is also |
| * permitted to be null, to enable aggressive testing, although in real |
| * life a Guice-supplied Provider will never return null. |
| */ |
| public static <T> Provider<T> of(final T instance) { |
| return new Provider<T>() { |
| public T get() { |
| return instance; |
| } |
| |
| @Override public String toString() { |
| return "of(" + instance + ")"; |
| } |
| }; |
| } |
| |
| /** |
| * Returns a Guice-friendly {@code com.google.inject.Provider} for the given |
| * JSR-330 {@code javax.inject.Provider}. The converse method is unnecessary, |
| * since Guice providers directly implement the JSR-330 interface. |
| * |
| * @since 3.0 |
| */ |
| public static <T> Provider<T> guicify(javax.inject.Provider<T> provider) { |
| if (provider instanceof Provider) { |
| return (Provider<T>) provider; |
| } |
| |
| final javax.inject.Provider<T> delegate = checkNotNull(provider, "provider"); |
| |
| // Ensure that we inject all injection points from the delegate provider. |
| Set<InjectionPoint> injectionPoints = |
| InjectionPoint.forInstanceMethodsAndFields(provider.getClass()); |
| if(injectionPoints.isEmpty()) { |
| return new Provider<T>() { |
| public T get() { |
| return delegate.get(); |
| } |
| |
| @Override public String toString() { |
| return "guicified(" + delegate + ")"; |
| } |
| }; |
| } else { |
| Set<Dependency<?>> mutableDeps = Sets.newHashSet(); |
| for(InjectionPoint ip : injectionPoints) { |
| mutableDeps.addAll(ip.getDependencies()); |
| } |
| final Set<Dependency<?>> dependencies = ImmutableSet.copyOf(mutableDeps); |
| return new ProviderWithDependencies<T>() { |
| @SuppressWarnings("unused") |
| @Inject |
| void initialize(Injector injector) { |
| injector.injectMembers(delegate); |
| } |
| |
| public Set<Dependency<?>> getDependencies() { |
| return dependencies; |
| } |
| |
| public T get() { |
| return delegate.get(); |
| } |
| |
| @Override public String toString() { |
| return "guicified(" + delegate + ")"; |
| } |
| }; |
| } |
| } |
| } |