03 storm 源码阅读 storm的进程间消息通信实现clojure端 加载java端netty能力

<pre name="code" class="java">;; Licensed to the Apache Software Foundation (ASF) under one;; or more contributor license agreements.  See the NOTICE file;; distributed with this work for additional information;; regarding copyright ownership.  The ASF licenses this file;; to you 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.;;;;主要负责调用java端的进程间通信的接口，包了一层，这样就可以通过它实现在clojure主逻辑做进程间通信。（后期版本是netty实现）;;;;mk-context 调用 LocalContext，LocalContext调用 LocalConnection ，LocalConnection 调用add-queue ;;对外暴露一个  mk-context函数，返回LocalContext。 就可以使用进程间通信。(ns backtype.storm.messaging.local  (:refer-clojure :exclude [send])  (:use [backtype.storm log])  (:import [backtype.storm.messaging IContext IConnection TaskMessage])  (:import [java.util.concurrent LinkedBlockingQueue])  (:import [java.util Map Iterator])  (:import [java.util Iterator ArrayList])  (:gen-class));;这是有个方法。添加队列的。辅助方法(defn add-queue! [queues-map lock storm-id port]  (let [id (str storm-id "-" port)]    (locking lock      (when-not (contains? @queues-map id)        (swap! queues-map assoc id (LinkedBlockingQueue.))))    (@queues-map id)));;这个是java那边netty映射到clojure端的conection(deftype LocalConnection [storm-id port queues-map lock queue]  IConnection  (^Iterator recv [this ^int flags ^int clientId]    (when-not queue      (throw (IllegalArgumentException. "Cannot receive on this socket")))    (let [ret (ArrayList.)          msg (if (= flags 1) (.poll queue) (.take queue))]      (if msg        (do           (.add ret msg)          (.iterator ret))        nil)))  (^void send [this ^int taskId ^bytes payload]    (let [send-queue (add-queue! queues-map lock storm-id port)]      (.put send-queue (TaskMessage. taskId payload))      ))  (^void send [this ^Iterator iter]    (let [send-queue (add-queue! queues-map lock storm-id port)]      (while (.hasNext iter)          (.put send-queue (.next iter)))      ))  (^void close [this]    ));;这个是java那边netty映射到clojure端的Context，里面持有LocalConnection(deftype LocalContext [^{:unsynchronized-mutable true} queues-map                       ^{:unsynchronized-mutable true} lock]  IContext  (^void prepare [this ^Map storm-conf]    (set! queues-map (atom {}))    (set! lock (Object.)))  (^IConnection bind [this ^String storm-id ^int port]    (LocalConnection. storm-id port queues-map lock (add-queue! queues-map lock storm-id port)))  (^IConnection connect [this ^String storm-id ^String host ^int port]    (LocalConnection. storm-id port queues-map lock nil))  (^void term [this]    ));;这个返回LocalContext，给主流程做消息传递逻辑(defn mk-context []   (let [context  (LocalContext. nil nil)]    (.prepare ^IContext context nil)    context))