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 * Configuration.java
029 * ------------------
030 * (C)opyright 2002-2005, by Thomas Morgner and Contributors.
031 *
032 * Original Author:  Thomas Morgner (taquera@sherito.org);
033 * Contributor(s):   David Gilbert (for Object Refinery Limited);
034 *
035 * $Id: Configuration.java,v 1.8 2007/11/02 17:50:37 taqua Exp $
036 *
037 * Changes
038 * -------
039 * 02-May-2003 : Initial version (TM);
040 * 
041 */
042
043package org.jfree.util;
044
045import java.io.Serializable;
046import java.util.Enumeration;
047import java.util.Iterator;
048
049/**
050 * A simple query interface for a configuration.
051 *
052 * @author Thomas Morgner
053 */
054public interface Configuration extends Serializable, Cloneable {
055
056    /**
057     * Returns the configuration property with the specified key.
058     *
059     * @param key  the property key.
060     *
061     * @return the property value.
062     */
063    public String getConfigProperty(String key);
064
065    /**
066     * Returns the configuration property with the specified key (or the 
067     * specified default value if there is no such property).
068     * <p>
069     * If the property is not defined in this configuration, the code will 
070     * lookup the property in the parent configuration.
071     *
072     * @param key  the property key.
073     * @param defaultValue  the default value.
074     *
075     * @return the property value.
076     */
077    public String getConfigProperty(String key, String defaultValue);
078
079    /**
080     * Returns all keys with the given prefix.
081     *
082     * @param prefix the prefix
083     * @return the iterator containing all keys with that prefix
084     */
085    public Iterator findPropertyKeys(String prefix);
086
087    /**
088     * Returns the configuration properties.
089     * 
090     * @return The configuration properties.
091     */
092    public Enumeration getConfigProperties();
093  
094    /**
095     * Returns a clone of the object.
096     *
097     * @return A clone.
098     *
099     * @throws CloneNotSupportedException if cloning is not supported for some reason.
100     */
101    public Object clone() throws CloneNotSupportedException;
102
103}