console/react/src/common/amqp/correlator.js

/*
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.
*/

import { utils } from "./utilities";

class Correlator {
  constructor() {
    this._objects = {};
    this._correlationID = 0;
    this.maxCorrelatorDepth = 10;
  }
  corr = () => `${++this._correlationID}`;

  // Associate this correlation id with the promise's resolve and reject methods
  register(id, resolve, reject) {
    this._objects[id] = { resolver: resolve, rejector: reject };
  }
  // Call the promise's resolve method.
  // This is called by rhea's receiver.on('message') function
  resolve(context) {
    var correlationID = context.message.correlation_id;
    // call the promise's resolve function with a copy of the rhea response (so we don't keep any references to internal rhea data)
    if (this._objects[correlationID]) {
      this._objects[correlationID].resolver({
        response: utils.copy(context.message.body),
        context: context
      });
    } else {
      console.log(
        `recieved message without a corresponding correlationID ${correlationID}`
      );
    }
    delete this._objects[correlationID];
  }
  reject(id, error) {
    this._objects[id].rejector(error);
    delete this._objects[id];
  }
  // Return the number of requests that can be sent before we start queuing requests
  depth() {
    return Math.max(1, this.maxCorrelatorDepth - Object.keys(this._objects).length);
  }
}

export default Correlator;