extras/japi/java/jvpp-registry/io/fd/vpp/jvpp/future/AbstractFutureJVppInvoker.java

   1 /*
   2  * Copyright (c) 2016 Cisco and/or its affiliates.
   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 io.fd.vpp.jvpp.future;
  18
  19
  20 import java.util.Map;
  21 import java.util.Objects;
  22 import java.util.concurrent.CompletableFuture;
  23 import java.util.concurrent.CompletionStage;
  24
  25 import io.fd.vpp.jvpp.JVpp;
  26 import io.fd.vpp.jvpp.JVppRegistry;
  27 import io.fd.vpp.jvpp.VppInvocationException;
  28 import io.fd.vpp.jvpp.dto.JVppDump;
  29 import io.fd.vpp.jvpp.dto.JVppReply;
  30 import io.fd.vpp.jvpp.dto.JVppReplyDump;
  31 import io.fd.vpp.jvpp.dto.JVppRequest;
  32
  33 /**
  34  * Future facade on top of JVpp
  35  */
  36 public abstract class AbstractFutureJVppInvoker implements FutureJVppInvoker {
  37
  38     private final JVpp jvpp;
  39     private final JVppRegistry registry;
  40
  41     /**
  42      * Guarded by self
  43      */
  44     private final Map<Integer, CompletableFuture<? extends JVppReply<?>>> requests;
  45
  46     protected AbstractFutureJVppInvoker(final JVpp jvpp, final JVppRegistry registry,
  47                                         final Map<Integer, CompletableFuture<? extends JVppReply<?>>> requestMap) {
  48         this.jvpp =  Objects.requireNonNull(jvpp, "jvpp should not be null");
  49         this.registry =  Objects.requireNonNull(registry, "registry should not be null");
  50         // Request map represents the shared state between this facade and it's callback
  51         // where facade puts futures in and callback completes + removes them
  52         this.requests = Objects.requireNonNull(requestMap, "Null requestMap");
  53     }
  54
  55     protected final Map<Integer, CompletableFuture<? extends JVppReply<?>>> getRequests() {
  56         synchronized (requests) {
  57             return requests;
  58         }
  59     }
  60
  61     // TODO use Optional in Future, java8
  62
  63     @Override
  64     @SuppressWarnings("unchecked")
  65     public <REQ extends JVppRequest, REPLY extends JVppReply<REQ>> CompletionStage<REPLY> send(REQ req) {
  66         try {
  67             // jvpp.send() can go to waiting state if sending queue is full, putting it into same
  68             // synchronization block as used by receiving part (synchronized(requests)) can lead
  69             // to deadlock between these two sides or at least slowing sending process by slow
  70             // reader
  71             final CompletableFuture<REPLY> replyCompletableFuture;
  72             final int contextId = jvpp.send(req);
  73
  74             if(req instanceof JVppDump) {
  75                 throw new IllegalArgumentException("Send with empty reply dump has to be used in case of dump calls");
  76             }
  77
  78             synchronized(requests) {
  79                 CompletableFuture<? extends JVppReply<?>> replyFuture = requests.get(contextId);
  80                 if (replyFuture == null) {
  81                     // reply not yet received, put new future into map
  82                     replyCompletableFuture = new CompletableFuture<>();
  83                     requests.put(contextId, replyCompletableFuture);
  84                 } else {
  85                     // reply already received (should be completed by reader),
  86                     // remove future from map and return it to caller
  87                     replyCompletableFuture = (CompletableFuture<REPLY>) replyFuture;
  88                     requests.remove(contextId);
  89                 }
  90             }
  91
  92             // TODO in case of timeouts/missing replies, requests from the map are not removed
  93             // consider adding cancel method, that would remove requests from the map and cancel
  94             // associated replyCompletableFuture
  95
  96             return replyCompletableFuture;
  97         } catch (VppInvocationException ex) {
  98             final CompletableFuture<REPLY> replyCompletableFuture = new CompletableFuture<>();
  99             replyCompletableFuture.completeExceptionally(ex);
 100             return replyCompletableFuture;
 101         }
 102     }
 103
 104     @Override
 105     @SuppressWarnings("unchecked")
 106     public <REQ extends JVppRequest, REPLY extends JVppReply<REQ>, DUMP extends JVppReplyDump<REQ, REPLY>> CompletionStage<DUMP> send(
 107             REQ req, DUMP emptyReplyDump) {
 108       try {
 109           // jvpp.send() and registry.controlPing() can go to waiting state if sending queue is full,
 110           // putting it into same synchronization block as used by receiving part (synchronized(requests))
 111           // can lead to deadlock between these two sides or at least slowing sending process by slow reader
 112           final CompletableDumpFuture<DUMP> replyDumpFuture;
 113           final int contextId = jvpp.send(req);
 114
 115           if(!(req instanceof JVppDump)) {
 116               throw new IllegalArgumentException("Send without empty reply dump has to be used in case of regular calls");
 117           }
 118
 119           synchronized(requests) {
 120               CompletableFuture<? extends JVppReply<?>> replyFuture = requests.get(contextId);
 121               if (replyFuture == null) {
 122                   // reply not received yet, put new future to map
 123                   replyDumpFuture = new CompletableDumpFuture<>(contextId, emptyReplyDump);
 124                   requests.put(contextId, replyDumpFuture);
 125               } else {
 126                   // reply already received, save existing future
 127                   replyDumpFuture = (CompletableDumpFuture<DUMP>) replyFuture;
 128               }
 129           }
 130
 131           final int pingId = registry.controlPing(jvpp.getClass());
 132
 133           synchronized(requests) {
 134               if (requests.remove(pingId) == null) {
 135                   // reply not received yet, put future into map under pingId
 136                   requests.put(pingId, replyDumpFuture);
 137               } else {
 138                   // reply already received, complete future
 139                   // ping reply couldn't complete the future because it is not in map under
 140                   // ping id
 141                   replyDumpFuture.complete(replyDumpFuture.getReplyDump());
 142                   requests.remove(contextId);
 143               }
 144           }
 145
 146           // TODO in case of timeouts/missing replies, requests from the map are not removed
 147           // consider adding cancel method, that would remove requests from the map and cancel
 148           // associated replyCompletableFuture
 149
 150           return replyDumpFuture;
 151       } catch (VppInvocationException ex) {
 152           final CompletableFuture<DUMP> replyCompletableFuture = new CompletableFuture<>();
 153           replyCompletableFuture.completeExceptionally(ex);
 154           return replyCompletableFuture;
 155       }
 156     }
 157
 158     public static final class CompletableDumpFuture<T extends JVppReplyDump<?, ?>> extends CompletableFuture<T> {
 159         private final T replyDump;
 160         private final int contextId;
 161
 162         public CompletableDumpFuture(final int contextId, final T emptyDump) {
 163             this.contextId = contextId;
 164             this.replyDump = emptyDump;
 165         }
 166
 167         public int getContextId() {
 168             return contextId;
 169         }
 170
 171         public T getReplyDump() {
 172             return replyDump;
 173         }
 174     }
 175
 176     @Override
 177     public void close() throws Exception {
 178         jvpp.close();
 179     }
 180 }