src/com/google/inject/Scope.java

/**
 * Copyright (C) 2006 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;

/**
 * A scope which bound objects can reside in. Mapping scopes by name with
 * {@link ContainerBuilder#scope} can help avoid compile time dependencies
 * on the {@code Scope} implementation (if desired) and enable the use of the
 * {@link Scoped} annotation.
 *
 * <p>Scope implementations should override {@link #toString} in the returned
 * factory and include the creator's {#toString} output. Doing so aids
 * debugging. They should also override their own {@link #toString}
 * method.
 *
 * @author crazybob@google.com (Bob Lee)
 */
public interface Scope {

  /**
   * Scopes a factory. The returned factory returns objects from this scope. If
   * an object does not exist in this scope, the factory can use the given
   * creator to create one.
   *
   * @param key binding key
   * @param creator creates new instances as needed
   * @return a new factory which only delegates to the given factory when an
   *     instance of the requested object doesn't already exist in the scope
   */
  public <T> Factory<T> scope(Key<T> key, Factory<T> creator);
}