source: branches/0.17.x/abcl/src/org/armedbear/lisp/ZipCache.java

/*
 * ZipCache.java
 *
 * Copyright (C) 2009 Erik Huelsmann
 * 
 * $Id: ZipCache.java 11998 2009-06-06 17:46:59Z ehuelsmann $
 *
 * This program 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
 * of the License, or (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * As a special exception, the copyright holders of this library give you
 * permission to link this library 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 library.  If you modify this library, 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 org.armedbear.lisp;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.zip.ZipFile;

/**
 *
 * @author Erik
 */
class ZipCache {

    static Map<String, Entry> zips = new HashMap<String, Entry>();
    
    synchronized static ZipFile getZip(String name) throws IOException {
        Entry zip = zips.get(name);
        
        if (zip == null)
            zips.put(name, zip = new Entry(new ZipFile(name)));

        zip.refcount++;
        return zip.value;
    }
    
    synchronized static void removeZip(String name) throws IOException {
        Entry zip = zips.get(name);

        if (zip == null)
            return;
        
        zip.refcount--;
        if (zip.refcount == 0) {
            zip.value.close();
            zips.remove(name);
        }
    }

    static class Entry {
        ZipFile value;
        int refcount = 0;

        Entry(ZipFile v) {
            value = v;
        }
    }

}