# ChartDeleter.java

    /* ===========================================================
     * JFreeChart : a free chart library for the Java(tm) platform
     * ===========================================================
     *
     * (C) Copyright 2000-2007, by Object Refinery Limited and Contributors.
     *
     * Project Info:  http://www.jfree.org/jfreechart/index.html
     *
     * 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.
     *
     * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
     * in the United States and other countries.]
     *
     * -----------------
     * ChartDeleter.java
     * -----------------
      * (C) Copyright 2002-2007, by Richard Atkinson and Contributors.
     *
     * Original Author:  Richard Atkinson;
     * Contributor(s):   -;
     *
     * Changes
     * -------
     * 19-Aug-2002 : Version 1;
     * 17-Oct-2002 : Fixed errors reported by Checkstyle (DG);
     * ------------- JFREECHART 1.0.x ---------------------------------------------
     * 02-Feb-2007 : Removed author tags all over JFreeChart sources (DG);
     *
     */
    package org.jfree.chart.servlet;

    import java.io.File;
    import java.io.Serializable;
    import java.util.Iterator;
    import java.util.List;

    import javax.servlet.http.HttpSessionBindingEvent;
    import javax.servlet.http.HttpSessionBindingListener;

    /**
     * Used for deleting charts from the temporary directory when the users session
     * expires.
     */
    public class ChartDeleter implements HttpSessionBindingListener, Serializable {

        /** The chart names. */
        private List chartNames = new java.util.ArrayList();

        /**
         * Blank constructor.
         */
        public ChartDeleter() {
            super();
        }

        /**
         * Add a chart to be deleted when the session expires
         *
         * @param filename  the name of the chart in the temporary directory to be
         *                  deleted.
         */
        public void addChart(String filename) {
            this.chartNames.add(filename);
        }

        /**
         * Checks to see if a chart is in the list of charts to be deleted
         *
         * @param filename  the name of the chart in the temporary directory.
         *
         * @return A boolean value indicating whether the chart is present in the
         *         list.
         */
        public boolean isChartAvailable(String filename) {
            return (this.chartNames.contains(filename));
        }

        /**
         * Binding this object to the session has no additional effects.
         *
         * @param event  the session bind event.
         */
        public void valueBound(HttpSessionBindingEvent event) {
            return;
        }

        /**
         * When this object is unbound from the session (including upon session
         * expiry) the files that have been added to the ArrayList are iterated
         * and deleted.
         *
         * @param event  the session unbind event.
         */
        public void valueUnbound(HttpSessionBindingEvent event) {

            Iterator iter = this.chartNames.listIterator();
            while (iter.hasNext()) {
                String filename = (String) iter.next();
                File file = new File(
                    System.getProperty("java.io.tmpdir"), filename
                );
                if (file.exists()) {
                    file.delete();
                }
            }
            return;

        }

    }