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XWork is an command-pattern framework that is used to power WebWork as well as other applications. XWork provides an Inversion of Control container, a powerful expression language, data type conversion, validation, and pluggable configuration.

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/**
 * 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.opensymphony.xwork2.inject;

import java.util.Set;
import java.io.Serializable;

/**
 * Injects dependencies into constructors, methods and fields annotated with
 * {@link Inject}. Immutable.
 *
 * When injecting a method or constructor, you can additionally annotate
 * its parameters with {@link Inject} and specify a dependency name. When a
 * parameter has no annotation, the container uses the name from the method or
 * constructor's {@link Inject} annotation respectively.
 *
 * 
For example:
 *
 * 
 *  class Foo {
 *
 *    // Inject the int constant named "i".
 *    @Inject("i") int i;
 *
 *    // Inject the default implementation of Bar and the String constant
 *    // named "s".
 *    @Inject Foo(Bar bar, @Inject("s") String s) {
 *      ...
 *    }
 *
 *    // Inject the default implementation of Baz and the Bob implementation
 *    // named "foo".
 *    @Inject void initialize(Baz baz, @Inject("foo") Bob bob) {
 *      ...
 *    }
 *
 *    // Inject the default implementation of Tee.
 *    @Inject void setTee(Tee tee) {
 *      ...
 *    }
 *  }
 * 
 *
 * To create and inject an instance of {@code Foo}:
 *
 * 
 *  Container c = ...;
 *  Foo foo = c.inject(Foo.class);
 * 
 *
 * @see ContainerBuilder
 * @author [email protected] (Bob Lee)
 */
public interface Container extends Serializable {

  /**
   * Default dependency name.
   */
  String DEFAULT_NAME = "default";

  /**
   * Injects dependencies into the fields and methods of an existing object.
   */
  void inject(Object o);

  /**
   * Creates and injects a new instance of type {@code implementation}.
   */
   T inject(Class implementation);

  /**
   * Gets an instance of the given dependency which was declared in
   * {@link com.opensymphony.xwork2.inject.ContainerBuilder}.
   */
   T getInstance(Class type, String name);

  /**
   * Convenience method. Equivalent to {@code getInstance(type,
   * DEFAULT_NAME)}.
   */
   T getInstance(Class type);
  
  /**
   * Gets a set of all registered names for the given type
   * @param type The instance type
   * @return A set of registered names
   */
  Set getInstanceNames(Class type);

  /**
   * Sets the scope strategy for the current thread.
   */
  void setScopeStrategy(Scope.Strategy scopeStrategy);

  /**
   * Removes the scope strategy for the current thread.
   */
  void removeScopeStrategy();
}