core/src/com/google/inject/spi/BindingScopingVisitor.java

/**
 * Copyright (C) 2008 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.spi;

import com.google.inject.Scope;
import java.lang.annotation.Annotation;

/**
 * Visits each of the strategies used to scope an injection.
 *
 * @param <V> any type to be returned by the visit method. Use {@link Void} with
 *     {@code return null} if no return type is needed.
 * @since 2.0
 */
public interface BindingScopingVisitor<V> {

  /**
   * Visit an eager singleton or single instance. This scope strategy is found on both module and
   * injector bindings.
   */
  V visitEagerSingleton();

  /**
   * Visit a scope instance. This scope strategy is found on both module and injector bindings.
   */
  V visitScope(Scope scope);

  /**
   * Visit a scope annotation. This scope strategy is found only on module bindings. The instance
   * that implements this scope is registered by {@link com.google.inject.Binder#bindScope(Class,
   * Scope) Binder.bindScope()}.
   */
  V visitScopeAnnotation(Class<? extends Annotation> scopeAnnotation);

  /**
   * Visit an unspecified or unscoped strategy. On a module, this strategy indicates that the
   * injector should use scoping annotations to find a scope. On an injector, it indicates that
   * no scope is applied to the binding. An unscoped binding will behave like a scoped one when it
   * is linked to a scoped binding.
   */
  V visitNoScoping();
}