systempropertyconfiguration.java

这是一个segy数据显示程序

/**
 * ========================================
 * JFreeReport : a free Java report library
 * ========================================
 *
 * Project Info:  http://www.jfree.org/jfreereport/index.html
 * Project Lead:  Thomas Morgner;
 *
 * (C) Copyright 2000-2003, by Simba Management Limited and Contributors.
 *
 * 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., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 * --------------------------------
 * SystemPropertyConfiguration.java
 * --------------------------------
 * (C)opyright 2000-2003, by Simba Management Limited.
 *
 * Original Author:  Thomas Morger
 * Contributor(s):   Stefan Prange;
 *
 * $Id: SystemPropertyConfiguration.java,v 1.1 2004/06/01 13:40:18 taqua 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>PropertyFileReportConfiguration</code>.
   */
  public SystemPropertyConfiguration()
  {
    // the configuration set of ReportConfiguration is not filled, we handle request
    // by using an own implementation...
  }

  /**
   * 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();
    }
  }
}