URLTracker.java

/*
 * Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * 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.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 */

package com.sun.btrace.samples;

import com.sun.btrace.annotations.OnMethod;
import com.sun.btrace.annotations.Kind;
import com.sun.btrace.annotations.BTrace;
import com.sun.btrace.annotations.Location;
import com.sun.btrace.annotations.TLS;
import com.sun.btrace.dtrace.D;
import static com.sun.btrace.ext.Printer.*;
import com.sun.btrace.ext.Strings;
import java.net.*;

/*
 * This sample prints every Java URL openURL and
 * openConnection (successful) attempts. In addition,
 * on platforms where DTrace is available, it runs
 * the D-script jurls.d -- which collects a histogram
 * of URL accesses by a btrace:::event probe. From this
 * BTrace program we raise that DTrace probe (dtraceProbe
 * call). Note that it is possible to do similar histogram
 * in BTrace itself (see Histogram.java). But, this sample
 * shows DTrace/BTrace integration as well. On exit, all
 * DTrace aggregates are printed by BTrace (i.e., the ones
 * that are not explicitly printed by DTrace printa call).
 */
@BTrace public class URLTracker {
    static {
        D.submitFile("jurls.d");
    }
    @TLS private static URL url;

    @OnMethod(
        clazz="java.net.URL",
        method="openConnection"
    )
    public static void openURL(URL self) {
        url = self;
    }

    @OnMethod(
        clazz="java.net.URL",
        method="openConnection"
    )
    public static void openURL(URL self, Proxy p) {
        url = self;
    }

    @OnMethod(
        clazz="java.net.URL",
        method="openConnection",
        location=@Location(Kind.RETURN)
    )
    public static void openURL() {
        if (url != null) {
            println(Strings.strcat("open ", Strings.str(url)));
            D.probe("java-url-open", Strings.str(url));
            url = null;
        }
    }
}