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      1 /*
      2  * Copyright 2009 Mike Cumings
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *   http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.kenai.jbosh;
     18 
     19 import java.util.concurrent.locks.Condition;
     20 import java.util.concurrent.locks.Lock;
     21 import java.util.concurrent.locks.ReentrantLock;
     22 import java.util.logging.Level;
     23 import java.util.logging.Logger;
     24 
     25 /**
     26  * A request and response pair representing a single exchange with a remote
     27  * content manager.  This is primarily a container class intended to maintain
     28  * the relationship between the request and response but allows the response
     29  * to be added after the fact.
     30  */
     31 final class HTTPExchange {
     32 
     33     /**
     34      * Logger.
     35      */
     36     private static final Logger LOG =
     37             Logger.getLogger(HTTPExchange.class.getName());
     38 
     39     /**
     40      * Request body.
     41      */
     42     private final AbstractBody request;
     43 
     44     /**
     45      * Lock instance used to protect and provide conditions.
     46      */
     47     private final Lock lock = new ReentrantLock();
     48 
     49     /**
     50      * Condition used to signal when the response has been set.
     51      */
     52     private final Condition ready = lock.newCondition();
     53 
     54     /**
     55      * HTTPResponse instance.
     56      */
     57     private HTTPResponse response;
     58 
     59     ///////////////////////////////////////////////////////////////////////////
     60     // Constructor:
     61 
     62     /**
     63      * Create a new request/response pair object.
     64      *
     65      * @param req request message body
     66      */
     67     HTTPExchange(final AbstractBody req) {
     68         if (req == null) {
     69             throw(new IllegalArgumentException("Request body cannot be null"));
     70         }
     71         request = req;
     72     }
     73 
     74     ///////////////////////////////////////////////////////////////////////////
     75     // Package-private methods:
     76 
     77     /**
     78      * Get the original request message.
     79      *
     80      * @return request message body.
     81      */
     82     AbstractBody getRequest() {
     83         return request;
     84     }
     85 
     86     /**
     87      * Set the HTTPResponse instance.
     88      *
     89      * @return HTTPResponse instance associated with the request.
     90      */
     91     void setHTTPResponse(HTTPResponse resp) {
     92         lock.lock();
     93         try {
     94             if (response != null) {
     95                 throw(new IllegalStateException(
     96                         "HTTPResponse was already set"));
     97             }
     98             response = resp;
     99             ready.signalAll();
    100         } finally {
    101             lock.unlock();
    102         }
    103     }
    104 
    105     /**
    106      * Get the HTTPResponse instance.
    107      *
    108      * @return HTTPResponse instance associated with the request.
    109      */
    110     HTTPResponse getHTTPResponse() {
    111         lock.lock();
    112         try {
    113             while (response == null) {
    114                 try {
    115                     ready.await();
    116                 } catch (InterruptedException intx) {
    117                     LOG.log(Level.FINEST, "Interrupted", intx);
    118                 }
    119             }
    120             return response;
    121         } finally {
    122             lock.unlock();
    123         }
    124     }
    125 
    126 }
    127