B4J Question MQTT broker messages

[jayel]

Hello,

I subscribe to $SYS/# messages but I get an error when I start my B4J program.

Waiting for debugger to connect...
Program started.
REMOTE : true
Connected: true
Error occurred on line: 47 (Connector)
java.io.EOFException: Unexpected end of ZLIB input stream
at java.util.zip.InflaterInputStream.fill(InflaterInputStream.java:240)
at java.util.zip.InflaterInputStream.read(InflaterInputStream.java:158)
at java.util.zip.InflaterInputStream.read(InflaterInputStream.java:122)
at java.io.DataInputStream.readByte(DataInputStream.java:265)
at anywheresoftware.b4a.randomaccessfile.B4XSerializator.readByte(B4XSerializator.java:131)
at anywheresoftware.b4a.randomaccessfile.B4XSerializator.readObject(B4XSerializator.java:299)
at anywheresoftware.b4a.randomaccessfile.B4XSerializator.ReadObject(B4XSerializator.java:110)
at anywheresoftware.b4a.randomaccessfile.B4XSerializator.ConvertBytesToObject(B4XSerializator.java:81)
at b4j.example.connector._client_messagearrived(connector.java:122)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:612)
at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:229)
at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:159)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at anywheresoftware.b4a.BA.raiseEvent2(BA.java:93)
at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:90)
at anywheresoftware.b4a.BA$3.run(BA.java:178)
at anywheresoftware.b4a.keywords.SimpleMessageLoop.runMessageLoop(SimpleMessageLoop.java:30)
at anywheresoftware.b4a.StandardBA.startMessageLoop(StandardBA.java:26)
at anywheresoftware.b4a.ShellBA.startMessageLoop(ShellBA.java:111)
at anywheresoftware.b4a.keywords.Common.StartMessageLoop(Common.java:131)
at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:301)
at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:159)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at anywheresoftware.b4a.BA.raiseEvent2(BA.java:93)
at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:90)
at anywheresoftware.b4a.BA.raiseEvent(BA.java:84)
at b4j.example.main.main(main.java:29)

I want to receive the messages from the Broker (SYS), how many clients connected, what connection has been rejected because wrong password or username, etc....

John

 

[Erel]

You can only use B4XSerializator to read messages if the messages were created with B4XSerializator.
In this case you need to check the topic id and read the bytes directly (with BytesToString).

 

[jayel]

Thx Erel