how do I check if a Client has connected

Core Library Questions

mrumunhum

how do I check if a Client has connected

in Core Library Questions • 2 years ago

This did not work:
C = null;
C = new Client ( this, "0.0.0.0", 5402 );
if( C == null ) println( "Client failed" );

Any time I reference C.anything, I get java.lang.NullPointerException

William Estrada
Mt Umunhum, CA, USA
HTTP://64.124.13.3 ( Mt-Umunhum-Wireless.net )
Skype: MrUmunhum

Replies(3)

PhiLho

Re: how do I check if a Client has connected

2 years ago

Well, you answered yourself to your question...
I hope you don't really use a null IP address...

mrumunhum

Re: how do I check if a Client has connected

2 years ago

What are you saying? It doesn't work.

This is the code:

C = new Client ( this, "0.0.0.0", 5402 );

if( C == null ) println( "Client failed" );
if( C != null ) println( "Client opened" );
println( C.ip() ); <=== STOPS HERE

This is what is generated:

java.net.ConnectException: Connection refused
    at java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:351)
    at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:211)
    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:200)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
    at java.net.Socket.connect(Socket.java:529)
    at java.net.Socket.connect(Socket.java:478)
    at java.net.Socket.<init>(Socket.java:375)
    at java.net.Socket.<init>(Socket.java:189)
    at processing.net.Client.<init>(Unknown Source)
    at Snake_Chart.setup(Snake_Chart.java:76)
    at processing.core.PApplet.handleDraw(Unknown Source)
    at processing.core.PApplet.run(Unknown Source)
    at java.lang.Thread.run(Thread.java:662)
Client opened
Exception in thread "Animation Thread" java.lang.NullPointerException
    at processing.net.Client.ip(Unknown Source)
    at Snake_Chart.setup(Snake_Chart.java:81)
    at processing.core.PApplet.handleDraw(Unknown Source)
    at processing.core.PApplet.run(Unknown Source)
    at java.lang.Thread.run(Thread.java:662)

William Estrada
Mt Umunhum, CA, USA
HTTP://64.124.13.3 ( Mt-Umunhum-Wireless.net )
Skype: MrUmunhum

PhiLho

Re: how do I check if a Client has connected

2 years ago

1) If C is null, it means you didn't connect, so don't try to use C in this case. That's the point of error checking...
2) Don't use 0.0.0.0. I doubt the server's IP address looks like that. Either 0.0.0.0 isn't valid or is used for broadcasting (fuzzy memory) but it shouldn't be used for client/server communication.

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