/*

 * $Id$

 *

 * Copyright (C) 2003-2009 JNode.org

 *

 * This library is free software; you can redistribute it and/or modify it

 * under the terms of the GNU Lesser General Public License as published

 * by the Free Software Foundation; either version 2.1 of the License, or

 * (at your option) any later version.

 *

 * This library 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 Lesser General Public 

 * License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public License

 * along with this library; If not, write to the Free Software Foundation, Inc., 

 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

 */

package org.jnode.vm.memmgr.generational;

import java.io.IOException;

import java.util.TreeMap;

import org.jnode.util.NumberUtils;

import org.jnode.vm.memmgr.HeapStatistics;

/**

 * @author Martin Husted Hartvig (hagar@jnode.org)

 */

public final class GenHeapStatistics extends HeapStatistics {

    private int minInstanceCount = 0;

    private long minTotalSize = 0;

    private final TreeMap<String, HeapCounter> countData = new TreeMap<String, HeapCounter>();

    private static final char newline = '\n';

    public boolean contains(String classname) {

        return countData.containsKey(classname);

    }

    public void add(String className, int size) {

        HeapCounter count = (HeapCounter) countData.get(className);

        if (count == null) {

            count = new HeapCounter(className, size);

            countData.put(className, count);

        }

        count.inc();

        count = null;

    }

    /**

     * Sets the minimum number of instances a class must have before it is

     * listed in toString.

     * 

     * @param count

     */

    public void setMinimumInstanceCount(int count) {

        this.minInstanceCount = count;

    }

    /**

     * Sets the minimum bytes of occupied memory by all instances of a class

     * before it is listed in toString.

     * 

     * @param bytes

     */

    public void setMinimumTotalSize(long bytes) {

        this.minTotalSize = bytes;

    }

    /**

     * {@inheritDoc}

     * 

     * @throws IOException

     */

    public void writeTo(Appendable a) throws IOException {

        boolean first = true;

        for (HeapCounter c : countData.values()) {

            if ((c.getInstanceCount() >= minInstanceCount) && (c.getTotalSize() >= minTotalSize)) {

                if (first) {

                    first = false;

                } else {

                    a.append(newline);

                }

                c.append(a);

            }

        }

    }

    /**

     * {@inheritDoc}

     */

    public String toString() {

        final StringBuilder sb = new StringBuilder();

        try {

            writeTo(sb);

        } catch (IOException e) {

            // normally, it will never happen

            throw new RuntimeException(e);

        }

        return sb.toString();

    }

    static final class HeapCounter {

        private final String name;

        private int instanceCount;

        private int objectSize = 0;

        private static final String usage = " memory usage=";

        public HeapCounter(String objectName, int objectSize) {

            this.name = objectName;

            this.objectSize = objectSize;

            this.instanceCount = 0;

        }

        public void inc() {

            instanceCount++;

        }

        public int getInstanceCount() {

            return instanceCount;

        }

        public int getObjectSize() {

            return objectSize;

        }

        public long getTotalSize() {

            return objectSize * (long) instanceCount;

        }

        public void append(Appendable a) throws IOException {

            a.append(name);

            a.append("  #");

            a.append(Integer.toString(instanceCount));

            if (objectSize != 0) {

                a.append(usage);

                long size = getTotalSize();

                if (size >= 1024) {

                    a.append(NumberUtils.toBinaryByte(size)).append(" (");

                    a.append(Long.toString(size)).append("b)");

                } else {

                    a.append(Long.toString(size)).append('b');

                }

            }

        }

    }

}