common/src/main/java/org/onap/so/client/dmaap/DmaapConsumer.java

   1 /*-
   2  * ============LICENSE_START=======================================================
   3  * ONAP - SO
   4  * ================================================================================
   5  * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
   6  * ================================================================================
   7  * Licensed under the Apache License, Version 2.0 (the "License");
   8  * you may not use this file except in compliance with the License.
   9  * You may obtain a copy of the License at
  10  *
  11  *      http://www.apache.org/licenses/LICENSE-2.0
  12  *
  13  * Unless required by applicable law or agreed to in writing, software
  14  * distributed under the License is distributed on an "AS IS" BASIS,
  15  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  16  * See the License for the specific language governing permissions and
  17  * limitations under the License.
  18  * ============LICENSE_END=========================================================
  19  */
  20
  21 package org.onap.so.client.dmaap;
  22
  23 import com.google.common.base.Stopwatch;
  24 import java.io.IOException;
  25 import java.util.concurrent.TimeUnit;
  26 import org.onap.so.client.dmaap.exceptions.DMaaPConsumerFailure;
  27 import org.onap.so.client.dmaap.exceptions.ExceededMaximumPollingTime;
  28 import org.onap.so.client.dmaap.rest.RestConsumer;
  29
  30 public abstract class DmaapConsumer extends DmaapClient {
  31
  32         public DmaapConsumer() throws IOException {
  33                 super("dmaap/default-consumer.properties");
  34         }
  35
  36         public Consumer getConsumer() {
  37                 return new RestConsumer(this.properties);
  38         }
  39
  40         public boolean consume() throws Exception {
  41             Consumer mrConsumer = this.getConsumer();
  42                 boolean accepted = false;
  43                 Stopwatch stopwatch = Stopwatch.createUnstarted();
  44                 try {
  45                         while (this.continuePolling()) {
  46                                 if (stopwatch.elapsed(TimeUnit.MILLISECONDS) >= this.getMaximumElapsedTime()) {
  47                                         final String message = "exceeded maximum retries on " + this.getRequestId() + " on " + this.getTopic();
  48                                         logger.error(message);
  49                                         throw new ExceededMaximumPollingTime(message);
  50                                 }
  51                                 stopwatch.start();
  52                                 Iterable<String> itr = mrConsumer.fetch();
  53                                 stopwatch.stop();
  54                                 for (String message : itr) {
  55                                         if (!accepted && this.isAccepted(message)) {
  56                                                 logger.info("accepted message found for " + this.getRequestId() + " on " + this.getTopic());
  57                                                 accepted = true;
  58                                         }
  59                                         if (accepted) {
  60                                                 logger.info("received dmaap message: " + message);
  61                                                 if (this.isFailure(message)) {
  62                                                         this.stopProcessingMessages();
  63                                                         final String errorMsg = "failure received from dmaap topic " + this.getTopic();
  64                                                         logger.error(errorMsg);
  65                                                         throw new DMaaPConsumerFailure(errorMsg);
  66                                                 } else {
  67                                                         this.processMessage(message);
  68                                                 }
  69                                         }
  70                                 }
  71                         }
  72                         return true;
  73                 } finally {
  74                         if (stopwatch.isRunning()) {
  75                                 stopwatch.stop();
  76                         }
  77                 }
  78         }
  79
  80         /**
  81          * Should this consumer continue to consume messages from the topic?
  82          * @return
  83          */
  84         public abstract boolean continuePolling();
  85         /**
  86          * Process a message from a DMaaP topic
  87          *
  88          * @param message
  89          * @throws Exception
  90          */
  91         public abstract void processMessage(String message) throws Exception;
  92         /**
  93          * Has the request been accepted by the receiving system?
  94          * Should the consumer move to processing messages?
  95          *
  96          * @param message
  97          * @return
  98          */
  99         public abstract boolean isAccepted(String message);
 100         /**
 101          * has the request failed?
 102          *
 103          * @param message
 104          * @return
 105          */
 106         public abstract boolean isFailure(String message);
 107         /**
 108          * The request id to filter messages on
 109          * @return
 110          */
 111         public abstract String getRequestId();
 112         /**
 113          * Logic that defines when the consumer should stop processing messages
 114          */
 115         public abstract void stopProcessingMessages();
 116
 117         /**
 118          * time in milliseconds
 119          */
 120         public int getMaximumElapsedTime() {
 121                 return 180000;
 122         }
 123
 124
 125
 126 }