content: /* ========================================================================
   * JCommon : a free general purpose class library for the Java(tm) platform
   * ========================================================================
   *
   * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
   * 
   * Project Info:  http://www.jfree.org/jcommon/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.]
   * 
   * --------------------------------
   * SystemPropertyConfiguration.java
   * --------------------------------
   * (C)opyright 2002-2004, by Thomas Morgner and Contributors.
   *
   * Original Author:  Thomas Morgner
   * Contributor(s):   Stefan Prange;
   *
   * $Id: SystemPropertyConfiguration.java,v 1.3 2005/10/18 13:14:12 mungady Exp $
   *
   * Changes (from 8-Feb-2002)
   * -------------------------
   * 14-Jan-2003 : Initial Version, moved from inner class of ReportConfiguration
   * 05-Feb-2003 : This implementation now handles SecurityExceptions.
   * 
   */
  
  package org.jfree.base.config;
  
  import java.util.Enumeration;
  import java.util.Vector;
  
  /**
   * A property configuration based on system properties.
   *
   * @author Thomas Morgner
   */
  public class SystemPropertyConfiguration extends HierarchicalConfiguration {
  
      /**
       * Creates a report configuration that includes all the system properties (whether they are
       * related to reports or not).  The parent configuration is a
       * <code>PropertyFileConfiguration</code>.
       */
      public SystemPropertyConfiguration() {
      }
  
      /**
       * Sets a configuration property.
       *
       * @param key  the property key.
       * @param value  the property value.
       */
      public void setConfigProperty(final String key, final String value) {
          throw new UnsupportedOperationException("The SystemPropertyConfiguration is readOnly");
      }
  
      /**
       * Returns the configuration property with the specified key (or the specified default value
       * if there is no such property).
       * <p>
       * If the property is not defined in this configuration, the code will lookup the property in
       * the parent configuration.
       *
       * @param key  the property key.
       * @param defaultValue  the default value.
       *
       * @return the property value.
       */
      public String getConfigProperty(final String key, final String defaultValue) {
          try {
              final String value = System.getProperty(key);
              if (value != null) {
                 return value;
              }
          }
          catch (SecurityException se) {
              // ignore security exceptions, continue as if the property was not set..
          }
          return super.getConfigProperty(key, defaultValue);
      }
  
      /**
       * Checks, whether the given key is locally defined in the system properties.
       * @see HierarchicalConfiguration#isLocallyDefined(java.lang.String)
       *
       * @param key the key that should be checked.
       * @return true, if the key is defined in the system properties, false otherwise.
       */
      public boolean isLocallyDefined(final String key) {
          try {
              return System.getProperties().containsKey(key);
          }
          catch (SecurityException se) {
              return false;
          }
      }
  
      /**
       * Returns all defined configuration properties for the report. The enumeration
       * contains all keys of the changed properties, properties set from files or
       * the system properties are not included.
       *
       * @return all defined configuration properties for the report.
       */
      public Enumeration getConfigProperties() {
          try {
              return System.getProperties().keys();
          }
          catch (SecurityException se) {
              // should return an empty enumeration ...
              return new Vector().elements();
          }
      }
  }
  