Java example source code file (FinalizerSummaryQuery.java)

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Java - Java tags/keywords

classes, comparator, enumeration, finalizer, finalizersummaryquery, hashmap, histogramelement, javaclass, javaheapobject, queryhandler, summary, total, util

The FinalizerSummaryQuery.java Java example source code

/*
 * Copyright (c) 1997, 2008, 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */


/*
 * The Original Code is HAT. The Initial Developer of the
 * Original Code is Bill Foote, with contributions from others
 * at JavaSoft/Sun.
 */

package com.sun.tools.hat.internal.server;

import com.sun.tools.hat.internal.model.*;
import java.util.*;

public class FinalizerSummaryQuery extends QueryHandler {
    public void run() {
        Enumeration objs = snapshot.getFinalizerObjects();
        startHtml("Finalizer Summary");

        out.println("<p align='center'>");
        out.println("<b>All Classes (excluding platform)");
        out.println("</p>");

        printFinalizerSummary(objs);
        endHtml();
    }

    private static class HistogramElement {
        public HistogramElement(JavaClass clazz) {
            this.clazz = clazz;
        }

        public void updateCount() {
            this.count++;
        }

        public int compare(HistogramElement other) {
            long diff = other.count - count;
            return (diff == 0L)? 0 : ((diff > 0L)? +1 : -1);
        }

        public JavaClass getClazz() {
            return clazz;
        }

        public long getCount() {
            return count;
        }

        private JavaClass clazz;
        private long count;
    }

    private void printFinalizerSummary(Enumeration objs) {
        int count = 0;
        Map<JavaClass, HistogramElement> map = new HashMap();

        while (objs.hasMoreElements()) {
            JavaHeapObject obj = (JavaHeapObject) objs.nextElement();
            count++;
            JavaClass clazz = obj.getClazz();
            if (! map.containsKey(clazz)) {
                map.put(clazz, new HistogramElement(clazz));
            }
            HistogramElement element = map.get(clazz);
            element.updateCount();
        }

        out.println("<p align='center'>");
        out.println("<b>");
        out.println("Total ");
        if (count != 0) {
            out.print("<a href='/finalizerObjects/'>instances");
        } else {
            out.print("instances");
        }
        out.println(" pending finalization: ");
        out.print(count);
        out.println("</b>
");

        if (count == 0) {
            return;
        }

        // calculate and print histogram
        HistogramElement[] elements = new HistogramElement[map.size()];
        map.values().toArray(elements);
        Arrays.sort(elements, new Comparator<HistogramElement>() {
                    public int compare(HistogramElement o1, HistogramElement o2) {
                        return o1.compare(o2);
                    }
                });

        out.println("<table border=1 align=center>");
        out.println("<tr>