com.hubspot.smtp.client

Interface SendInterceptor

All Known Implementing Classes:

CompositeSendInterceptor

public interface SendInterceptor

An extension point that supports intercepting commands and data before they are sent.

There are three methods to implement, each of which executes "around" the sending of a request, data or pipelined sequence of requests. The @{code aroundRequest} and aroundPipelinedSequence methods each receive an argument describing what is being sent. All methods receive a Supplier<CompletableFuture<List<SmtpResponse>>> called next that returns a future that will complete when the send has finished.

As an example, consider an interceptor used for timing commands. It can record the time before the command/data is sent, then log the difference when the next future completes.

  class TimingInterceptor implements SendInterceptor {
    private static final Logger LOG = LoggerFactory.getLogger(TimingInterceptor.class);

    public CompletableFuture<List<SmtpResponse>> aroundRequest(SmtpRequest request, Supplier<CompletableFuture<List<SmtpResponse>>> next) {
      long startedAt = System.currentTimeMillis();
      return next.get().whenComplete((response, throwable) -> LOG.debug("{}: {}ms", request, System.currentTimeMillis() - startedAt);
    }

    public CompletableFuture<List<SmtpResponse>> aroundData(Supplier<CompletableFuture<List<SmtpResponse>>> next) {
      long startedAt = System.currentTimeMillis();
      return next.get().whenComplete((response, throwable) -> LOG.debug("data: {}ms", System.currentTimeMillis() - startedAt);
    }

    public CompletableFuture<List<SmtpResponse>> aroundPipelinedSequence(List<SmtpRequest> requests, Supplier<CompletableFuture<List<SmtpResponse>>> next) {
      long startedAt = System.currentTimeMillis();
      return next.get().whenComplete((response, throwable) -> LOG.debug("{}: {}ms", requests, System.currentTimeMillis() - startedAt);
    }
  }

See Also:

CompositeSendInterceptor

Method Summary

Modifier and Type	Method and Description
CompletableFuture<List<io.netty.handler.codec.smtp.SmtpResponse>>	aroundData(Supplier<CompletableFuture<List<io.netty.handler.codec.smtp.SmtpResponse>>> next) Called before data is sent.
CompletableFuture<List<io.netty.handler.codec.smtp.SmtpResponse>>	aroundPipelinedSequence(List<io.netty.handler.codec.smtp.SmtpRequest> requests, Supplier<CompletableFuture<List<io.netty.handler.codec.smtp.SmtpResponse>>> next) Called before a pipelined series of requests is sent.
CompletableFuture<List<io.netty.handler.codec.smtp.SmtpResponse>>	aroundRequest(io.netty.handler.codec.smtp.SmtpRequest request, Supplier<CompletableFuture<List<io.netty.handler.codec.smtp.SmtpResponse>>> next) Called before a request is sent.

Method Detail

aroundRequest

CompletableFuture<List<io.netty.handler.codec.smtp.SmtpResponse>> aroundRequest(io.netty.handler.codec.smtp.SmtpRequest request,
                                                                                Supplier<CompletableFuture<List<io.netty.handler.codec.smtp.SmtpResponse>>> next)

Called before a request is sent.

Parameters:

request - the request that will be sent

next - supplies a future that will complete when the request has been sent and a response received

Returns:

next.get(), a CompletableFuture derived from it, or an exceptional future if the send should be aborted

aroundData

CompletableFuture<List<io.netty.handler.codec.smtp.SmtpResponse>> aroundData(Supplier<CompletableFuture<List<io.netty.handler.codec.smtp.SmtpResponse>>> next)

Called before data is sent.

Parameters:

next - supplies a future that will complete when the data has been sent and a response received

Returns:

next.get(), a CompletableFuture derived from it, or an exceptional future if the send should be aborted

aroundPipelinedSequence

CompletableFuture<List<io.netty.handler.codec.smtp.SmtpResponse>> aroundPipelinedSequence(List<io.netty.handler.codec.smtp.SmtpRequest> requests,
                                                                                          Supplier<CompletableFuture<List<io.netty.handler.codec.smtp.SmtpResponse>>> next)

Called before a pipelined series of requests is sent.

Parameters:

requests - the requests that will be sent

next - supplies a future that will complete when the requests have been sent and responses received

Returns:

next.get(), a CompletableFuture derived from it, or an exceptional future if the send should be aborted