core/src/com/google/inject/Guice.java

/*
 * 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;

import com.google.inject.internal.InternalInjectorCreator;
import java.util.Arrays;

/**
 * The entry point to the Guice framework. Creates {@link Injector}s from {@link Module}s.
 *
 * <p>Guice supports a model of development that draws clear boundaries between APIs,
 * Implementations of these APIs, Modules which configure these implementations, and finally
 * Applications which consist of a collection of Modules. It is the Application, which typically
 * defines your {@code main()} method, that bootstraps the Guice Injector using the {@code Guice}
 * class, as in this example:
 *
 * <pre>
 *     public class FooApplication {
 *       public static void main(String[] args) {
 *         Injector injector = Guice.createInjector(
 *             new ModuleA(),
 *             new ModuleB(),
 *             . . .
 *             new FooApplicationFlagsModule(args)
 *         );
 *
 *         // Now just bootstrap the application and you're done
 *         FooStarter starter = injector.getInstance(FooStarter.class);
 *         starter.runApplication();
 *       }
 *     }
 * </pre>
 */
public final class Guice {

  private Guice() {}

  /**
   * Creates an injector for the given set of modules. This is equivalent to calling {@link
   * #createInjector(Stage, Module...)} with Stage.DEVELOPMENT.
   *
   * @throws CreationException if one or more errors occur during injector construction
   */
  public static Injector createInjector(Module... modules) {
    return createInjector(Arrays.asList(modules));
  }

  /**
   * Creates an injector for the given set of modules. This is equivalent to calling {@link
   * #createInjector(Stage, Iterable)} with Stage.DEVELOPMENT.
   *
   * @throws CreationException if one or more errors occur during injector creation
   */
  public static Injector createInjector(Iterable<? extends Module> modules) {
    return createInjector(Stage.DEVELOPMENT, modules);
  }

  /**
   * Creates an injector for the given set of modules, in a given development stage.
   *
   * @throws CreationException if one or more errors occur during injector creation.
   */
  public static Injector createInjector(Stage stage, Module... modules) {
    return createInjector(stage, Arrays.asList(modules));
  }

  /**
   * Creates an injector for the given set of modules, in a given development stage.
   *
   * @throws CreationException if one or more errors occur during injector construction
   */
  public static Injector createInjector(Stage stage, Iterable<? extends Module> modules) {
    return new InternalInjectorCreator().stage(stage).addModules(modules).build();
  }
}