/*
 * Copyright 2012-2017 Red Hat, Inc.
 *
 * This file is part of Thermostat.
 *
 * Thermostat is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published
 * by the Free Software Foundation; either version 2, or (at your
 * option) any later version.
 *
 * Thermostat 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Thermostat; see the file COPYING.  If not see
 * <http://www.gnu.org/licenses/>.
 *
 * Linking this code with other modules is making a combined work
 * based on this code.  Thus, the terms and conditions of the GNU
 * General Public License cover the whole combination.
 *
 * As a special exception, the copyright holders of this code give
 * you permission to link this code with independent modules to
 * produce an executable, regardless of the license terms of these
 * independent modules, and to copy and distribute the resulting
 * executable under terms of your choice, provided that you also
 * meet, for each linked independent module, the terms and conditions
 * of the license of that module.  An independent module is a module
 * which is not derived from or based on this code.  If you modify
 * this code, you may extend this exception to your version of the
 * library, but you are not obligated to do so.  If you do not wish
 * to do so, delete this exception statement from your version.
 */

package com.redhat.thermostat.vm.heap.analysis.common;

import java.io.File;
import java.io.IOException;
import java.util.Enumeration;

import com.sun.tools.hat.internal.model.JavaHeapObject;
import com.sun.tools.hat.internal.model.Snapshot;
import com.sun.tools.hat.internal.parser.Reader;

public class HistogramLoader {

    public ObjectHistogram load(String filename) throws IOException {
        Snapshot snapshot = loadHeapdump(filename);
        return computeHistogram(snapshot);
    }

    private Snapshot loadHeapdump(String filename) throws IOException {
        File heapdump = new File(filename);
        Snapshot snapshot = Reader.readFile(heapdump.getAbsolutePath(), true, 0);
        snapshot.resolve(true);
        return snapshot;
    }

    private ObjectHistogram computeHistogram(Snapshot snapshot) {
        Enumeration<JavaHeapObject> thingos = snapshot.getThings();
        ObjectHistogram histogram = new ObjectHistogram();
        while (thingos.hasMoreElements()) {
            JavaHeapObject thingo = thingos.nextElement();
            histogram.addThing(thingo);
        }
        return histogram;
    }

}