    001    /* ========================================================================
    002     * JCommon : a free general purpose class library for the Java(tm) platform
    003     * ========================================================================
    004     *
    005     * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
    006     *
    007     * Project Info:  http://www.jfree.org/jcommon/index.html
    008     *
    009     * This library is free software; you can redistribute it and/or modify it
    010     * under the terms of the GNU Lesser General Public License as published by
    011     * the Free Software Foundation; either version 2.1 of the License, or
    012     * (at your option) any later version.
    013     *
    014     * This library is distributed in the hope that it will be useful, but
    015     * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    016     * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
    017     * License for more details.
    018     *
    019     * You should have received a copy of the GNU Lesser General Public
    020     * License along with this library; if not, write to the Free Software
    021     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
    022     * USA.
    023     *
    024     * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
    025     * in the United States and other countries.]
    026     *
    027     * -------------------------
    028     * DefaultConfiguration.java
    029     * -------------------------
    030     * (C)opyright 2003, 2004, by Thomas Morgner and Contributors.
    031     *
    032     * Original Author:  Thomas Morgner;
    033     * Contributor(s):   David Gilbert (for Object Refinery Limited);
    034     *
    035     * $Id: DefaultConfiguration.java,v 1.6 2008/09/10 09:21:30 mungady Exp $
    036     *
    037     * Changes
    038     * -------
    039     * 04.06.2003 : Initial version (TM);
    040     *
    041     */
    042
    043    package org.jfree.util;
    044
    045    import java.util.Collections;
    046    import java.util.Enumeration;
    047    import java.util.Iterator;
    048    import java.util.Properties;
    049    import java.util.TreeSet;
    050
    051    import org.jfree.base.config.ModifiableConfiguration;
    052
    053    /**
    054     * Default configuration.
    055     *
    056     * @author Thomas Morgner.
    057     */
    058    public class DefaultConfiguration extends Properties
    059        implements ModifiableConfiguration
    060    {
    061
    062      /**
    063       * Creates an empty property list with no default values.
    064       */
    065      public DefaultConfiguration()
    066      {
    067        super();
    068      }
    069
    070      /**
    071       * Returns the configuration property with the specified key.
    072       *
    073       * @param key the property key.
    074       * @return the property value.
    075       */
    076      public String getConfigProperty(final String key)
    077      {
    078        return getProperty(key);
    079      }
    080
    081      /**
    082       * Returns the configuration property with the specified key (or the
    083       * specified default value if there is no such property).
    084       * <p/>
    085       * If the property is not defined in this configuration, the code will
    086       * lookup the property in the parent configuration.
    087       *
    088       * @param key          the property key.
    089       * @param defaultValue the default value.
    090       * @return the property value.
    091       */
    092      public String getConfigProperty(final String key, final String defaultValue)
    093      {
    094        return getProperty(key, defaultValue);
    095      }
    096
    097      /**
    098       * Searches all property keys that start with a given prefix.
    099       *
    100       * @param prefix the prefix that all selected property keys should share
    101       * @return the properties as iterator.
    102       */
    103      public Iterator findPropertyKeys(final String prefix)
    104      {
    105        final TreeSet collector = new TreeSet();
    106        final Enumeration enum1 = keys();
    107        while (enum1.hasMoreElements())
    108        {
    109          final String key = (String) enum1.nextElement();
    110          if (key.startsWith(prefix))
    111          {
    112            if (collector.contains(key) == false)
    113            {
    114              collector.add(key);
    115            }
    116          }
    117        }
    118        return Collections.unmodifiableSet(collector).iterator();
    119      }
    120
    121      /**
    122       * Returns an enumeration of the property keys.
    123       *
    124       * @return An enumeration of the property keys.
    125       */
    126      public Enumeration getConfigProperties()
    127      {
    128        return keys();
    129      }
    130
    131      /**
    132       * Sets the value of a configuration property.
    133       *
    134       * @param key   the property key.
    135       * @param value the property value.
    136       */
    137      public void setConfigProperty(final String key, final String value)
    138      {
    139        if (value == null)
    140        {
    141          remove(key);
    142        }
    143        else
    144        {
    145          setProperty(key, value);
    146        }
    147      }
    148    }