How can write logs to a file in btrace?

Question

I have following btrace script. I would like to record entry and exit of functions in a specific class.

..
package com.sun.btrace.samples;

import com.sun.btrace.BTraceUtils;
import com.sun.btrace.Profiler;
import com.sun.btrace.annotations.*;
@BTrace class Profiling {
@Property
Profiler swingProfiler = BTraceUtils.Profiling.newProfiler();

@OnMethod(
    clazz="com.pkg.classname", 
    method="/.*/")
    void entry(@ProbeMethodName(fqn=true) String probeMethod) {
        BTraceUtils.print("Entry" );
        BTraceUtils.println(BTraceUtils.timestamp() );
        BTraceUtils.println(probeMethod);
    }

@OnMethod(
    clazz="com.pkg.classname", 
    location=@Location(value=Kind.RETURN)
    )
    void exit(@ProbeMethodName(fqn=true) String probeMethod, @Duration long duration) {
        BTraceUtils.print("Exit:" );
        BTraceUtils.println(BTraceUtils.timestamp() );
        BTraceUtils.println(probeMethod);
    }

}

This gives outout on the console. How could I write the result to a file? Btrace does not allow to create new objects.

(Obvious work around is redirect to a file. Another choice is to use VisualVM btrace plugin - the output then goes to visualVM window. Note sure if it an handle very large output 500Mb or so.)

Thanks

Answer 1

You can start your application with BTrace agent (http://kenai.com/projects/btrace/pages/UserGuide#btrace-agent). Then you can specify scriptOutputFile argument to the agent and all output generated by calls to println etc. will go to the specified file instead of the stdout.