ThreadCounterBean.java example

Explorer
btrace-master
/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
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 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the Classpath exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
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package com.sun.btrace.samples;

import com.sun.btrace.annotations.*;
import static com.sun.btrace.BTraceUtils.*;

/**
 * This sample demonstrates that you can expose a BTrace
 * class as a JMX MBean. After connecting BTrace to the
 * target application, connect VisualVM or jconsole or 
 * any other JMX client to the same application.
 */ 
@BTrace public class ThreadCounterBean {

    // @Property makes the count field to be exposed
    // as an attribute of this MBean.
    @Property
    private static long count;

    @OnMethod(
        clazz="java.lang.Thread",
        method="start"
    ) 
    public static void onnewThread(@Self Thread t) {
        count++;
    }

    @OnTimer(2000) 
    public static void ontimer() {
        println(count);
    }
}