聊聊artemis的BaseInterceptor

序

本文主要研究一下artemis的BaseInterceptor

BaseInterceptor

activemq-artemis-master/artemis-core-client/src/main/java/org/apache/activemq/artemis/api/core/BaseInterceptor.java

public interface BaseInterceptor<P> {

   /**
    * Intercepts a packet which is received before it is sent to the channel
    *
    * @param packet     the packet being received
    * @param connection the connection the packet was received on
    * @return {@code true} to process the next interceptor and handle the packet,
    * {@code false} to abort processing of the packet
    * @throws ActiveMQException
    */
   boolean intercept(P packet, RemotingConnection connection) throws ActiveMQException;

}

• BaseInterceptor定義了intercept方法，該方法返回true表示能夠繼續下一個interceptor，返回false表示終止packet的處理

AbstractProtocolManager

activemq-artemis-master/artemis-server/src/main/java/org/apache/activemq/artemis/spi/core/protocol/AbstractProtocolManager.java

public abstract class AbstractProtocolManager<P, I extends BaseInterceptor<P>, C extends RemotingConnection> implements ProtocolManager<I> {

   private final Map<SimpleString, RoutingType> prefixes = new HashMap<>();

   protected void invokeInterceptors(final List<I> interceptors, final P message, final C connection) {
      if (interceptors != null && !interceptors.isEmpty()) {
         for (I interceptor : interceptors) {
            try {
               if (!interceptor.intercept(message, connection)) {
                  break;
               }
            } catch (Exception e) {
               ActiveMQServerLogger.LOGGER.failedToInvokeAninterceptor(e);
            }
         }
      }
   }

   @Override
   public void setAnycastPrefix(String anycastPrefix) {
      for (String prefix : anycastPrefix.split(",")) {
         prefixes.put(SimpleString.toSimpleString(prefix), RoutingType.ANYCAST);
      }
   }

   @Override
   public void setMulticastPrefix(String multicastPrefix) {
      for (String prefix : multicastPrefix.split(",")) {
         prefixes.put(SimpleString.toSimpleString(prefix), RoutingType.MULTICAST);
      }
   }

   @Override
   public Map<SimpleString, RoutingType> getPrefixes() {
      return prefixes;
   }
}

• AbstractProtocolManager的invokeInterceptors方法接收interceptors，以後挨個遍歷interceptors，執行interceptor.intercept(message, connection)，若返回false則立馬終止循環

小結

BaseInterceptor定義了intercept方法，該方法返回true表示能夠繼續下一個interceptor，返回false表示終止packet的處理

doc

• BaseInterceptor