Trying to write a simple string to a socket's writeHandlerID

[murtuza chhil]

Hi,

When I try to use the writeHandleID of a socket as below , I get a cast exception, the NetSocket api expects a buffer. I understand I can use the socket, 

this is me trying to learn using the eventbus.

                        vertx.eventBus()
                             .send(netSocket.writeHandlerID(), "4TEST");

SEVERE: Failed to handleMessage. address: 5a56a125-fc81-4e36-a3b1-cbb10ed2b161
java.lang.ClassCastException: java.lang.String cannot be cast to io.vertx.core.buffer.Buffer
    at io.vertx.core.net.impl.NetSocketImpl.lambda$new$1(NetSocketImpl.java:95)
    at io.vertx.core.eventbus.impl.HandlerRegistration.deliver(HandlerRegistration.java:212)
    at io.vertx.core.eventbus.impl.HandlerRegistration.handle(HandlerRegistration.java:189)
    at io.vertx.core.eventbus.impl.EventBusImpl.lambda$deliverToHandler$3(EventBusImpl.java:538)
    at io.vertx.core.impl.ContextImpl.lambda$wrapTask$2(ContextImpl.java:344)
    at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:16

​

And when I pass a buffer, eventbus complains that it needs a codec as it doesn't understand buffers as it supports JSONObjects and Strings out of the box. 

                        vertx.eventBus()
                             .send(netSocket.writeHandlerID(), Buffer.buffer("4TEST"));

java.lang.IllegalArgumentException: No message codec for type: class io.vertx.reactivex.core.buffer.Buffer
    at io.vertx.core.eventbus.impl.CodecManager.lookupCodec(CodecManager.java:90)
    at io.vertx.core.eventbus.impl.clustered.ClusteredEventBus.createMessage(ClusteredEventBus.java:203)
    at io.vertx.core.eventbus.impl.EventBusImpl.send(EventBusImpl.java:110)
    at io.vertx.core.eventbus.impl.EventBusImpl.send(EventBusImpl.java:95)
    at chhil.vertx.example2.TCPServer.lambda$3(TCPServer.java:108)

​

Is there a codec for the simple conversion between vertx buffers and java strings?

Do I need to write one for this simple conversion? 

Do these writeHandlerIDs work across jvms and across machines boundaries in a cluster? 

Any help will be appreciated.

thanks

-chhil

[Julien Viet]

in your case you need to send an io.vertx.core.buffer.Buffer and not the reactive version.

it's because Java does not have reified generics it happens.

Julien

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[Grey Seal]

For the code snippet 1 that you have shared, there seems to be no address to handle the message. netSocket.writeHandlerID() is dynamic, and event bus looks for an already registered address to send the message to.

For the code snippet 2, you can send String/JsonObject as messages, so you have to get String/JsonObject from the buffer -> Buffer.buffer("4TEST").toString() as an example.

For more look at Vertx core doc and Vertx samples.

https://github.com/vert-x3/vertx-examples/blob/master/core-examples/src/main/java/io/vertx/example/core/eventbus/messagecodec/Sender.java

[murtuza chhil]

Thanks Julien,  

Using the correct Buffer import fixed it.

-chhil

[murtuza chhil]

Thank you Grey Seal for the response.

For the code snippet 1 that you have shared, there seems to be no address to handle the message. netSocket.writeHandlerID() is dynamic, and event bus looks for an already registered address to send the message to.

​

There is a connection and data has come over the socket, so I assume, the value is already registered by vertx internals.

For the code snippet 2, you can send String/JsonObject as messages, so you have to get String/JsonObject from the buffer -> Buffer.buffer(“4TEST”).toString() as an example.

​

I was using the reactive Buffer  instead of the non reactive one as Julien pointed out earlier. The  Buffer.buffer.tostring() does not work as the socket expects a Buffer.

When I do that ....

SEVERE: Unhandled exception
java.lang.ClassCastException: java.lang.String cannot be cast to io.vertx.core.buffer.Buffer
    at io.vertx.core.net.impl.NetSocketImpl.lambda$new$1(NetSocketImpl.java:95)
    at io.vertx.core.eventbus.impl.HandlerRegistration.deliver(HandlerRegistration.java:212)
    at io.vertx.core.eventbus.impl.HandlerRegistration.handle(HandlerRegistration.java:189)
    at io.vertx.core.eventbus.impl.EventBusImpl.lambda$deliverToHandler$3(EventBusImpl.java:538)
    at io.vertx.core.impl.ContextImpl.lambda$wrapTask$2(ContextImpl.java:344)

​

Thank you.

-chhil

[murtuza chhil]

Do these writeHandlerIDs work for verticles across jvms and across machines boundaries in a cluster?

-chhil

[Julien Viet]

they are local only.

On 19 Jan 2018, at 11:19, murtuza chhil <chi...@gmail.com> wrote:

Do these writeHandlerIDs work for verticles across jvms and across machines boundaries in a cluster?

-chhil

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[murtuza chhil]

Thank you, Julien.

-chhil