View Javadoc

1   /***
2    *
3    * Copyright 2004 Hiram Chirino
4    *
5    *  Licensed under the Apache License, Version 2.0 (the "License");
6    *  you may not use this file except in compliance with the License.
7    *  You may obtain a copy of the License at
8    *
9    *     http://www.apache.org/licenses/LICENSE-2.0
10   *
11   *  Unless required by applicable law or agreed to in writing, software
12   *  distributed under the License is distributed on an "AS IS" BASIS,
13   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   *  See the License for the specific language governing permissions and
15   *  limitations under the License.
16   */
17  
18  package org.activeio;
19  
20  
21  /***
22   * A Channel provides a standard procedure for regulating data transmission between 
23   * applications.
24   * 
25   * The activeio API encourages that layered wire protocols be created by wiring
26   * together a chain of Channel objects.   
27   * 
28   * @version $Revision$
29   */
30  public interface Channel extends Disposable, Service {
31      
32      /***
33       * Since a Channel may be composed from a chain of other Channel obejcts,
34       * this method allows you to query the chain for the specified {@param target} interface.
35       * 
36       * The first Channel in the chain the implments the requested interface will be return
37       * an implementing object.  If no Channel in the chain implements the requested class,
38       * then null is returned.
39       */
40      Object narrow(Class target);
41  }