PathBasedSystemSettings.java

/*
 * This program is free software; you can redistribute it and/or modify it under the 
 * terms of the GNU General Public License, version 2 as published by the Free Software 
 * Foundation.
 *
 * You should have received a copy of the GNU General Public License along with this 
 * program; if not, you can obtain a copy at http://www.gnu.org/licenses/gpl-2.0.html 
 * or from the Free Software Foundation, Inc., 
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * This program 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 General Public License for more details.
 *
 * Copyright 2007 - 2008 Pentaho Corporation.  All rights reserved. 
 * 
 */
package org.pentaho.platform.engine.core.system;

import java.io.File;
import java.io.IOException;
import java.util.List;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.pentaho.platform.util.xml.dom4j.XmlDom4JHelper;

/**
 * Behavior is identical to <code>SystemSettings</code> except that the settings
 * for <code>PentahoSystem</code> can live in an arbitrary location in the file system
 * (i.e. the file does not have to exist in the <repository>/system). The location of
 * the file used to initialize <code>PentahoSystem</code> is specified by the
 * <code>System</code> property whose key is <code>SYSTEM_CFG_PATH_KEY</code>.
 * If this key does not exist in the <code>System</code> properties, then this
 * class falls back on the behavior of SystemSettings (i.e. it gets the system
 * settings from <repository>/system/pentaho.xml).
 * 
 * @author Steven Barkdull
 *
 */
public class PathBasedSystemSettings extends SystemSettings {

  private static final long serialVersionUID = 666L;

  /**
   * key into System.property containing the path to the file
   * containing settings information for <code>PentahoSystem</code>.
   */
  public static final String SYSTEM_CFG_PATH_KEY = "PENTAHO_SYS_CFG_PATH"; //$NON-NLS-1$

  /**
   * the path to the file containing settings information for <code>PentahoSystem</code>.
   * if this is null, the system settings will be in <repository>/system/pentaho.xml
   */
  private String systemCfgPath;

  public PathBasedSystemSettings() {
    super();
    // NOTE: null is an acceptable value, if null, fall back to default
    systemCfgPath = System.getProperty(PathBasedSystemSettings.SYSTEM_CFG_PATH_KEY);
  }

  @Override
  public String getSystemSetting(final String settingName, final String defaultValue) {
    if (null != systemCfgPath) {
      return getSystemSetting(systemCfgPath, settingName, defaultValue);
    } else {
      // use default
      return super.getSystemSetting(settingName, defaultValue);
    }
  }

  @Override
  public List getSystemSettings(final String settingName) {
    if (null != systemCfgPath) {
      return getSystemSettings(systemCfgPath, settingName);
    } else {
      // use default
      return super.getSystemSettings(settingName);
    }
  }

  @Override
  protected String getAbsolutePath(final String path) {
    if (path.equals(systemCfgPath)) {
      return systemCfgPath;
    } else {
      // use default
      return super.getAbsolutePath(path);
    }
  }

  @Override
  public String getSystemCfgSourceName() {
    return null != systemCfgPath ? systemCfgPath : super.getSystemCfgSourceName();
  }
  

  @Override
  public Document getSettingsDocumentFromFile(File f) throws IOException, DocumentException {
    return XmlDom4JHelper.getDocFromFile(f, new PentahoDtdEntityResolver() );
  }

}