com.caucho.jsp.el.InitParamFieldExpression Maven / Gradle / Ivy

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/*
 * Copyright (c) 1998-2018 Caucho Technology -- all rights reserved
 *
 * This file is part of Resin(R) Open Source
 *
 * Each copy or derived work must preserve the copyright notice and this
 * notice unmodified.
 *
 * Resin Open Source is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Resin Open Source 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, or any warranty
 * of NON-INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Resin Open Source; if not, write to the
 *
 *   Free Software Foundation, Inc.
 *   59 Temple Place, Suite 330
 *   Boston, MA 02111-1307  USA
 *
 * @author Scott Ferguson
 */

package com.caucho.jsp.el;

import javax.el.ELContext;
import javax.el.ELException;
import javax.el.ELResolver;
import javax.servlet.ServletContext;

@SuppressWarnings("serial")
public class InitParamFieldExpression extends AbstractValueExpression
{
  private final String _field;
  
  InitParamFieldExpression(String field)
  {
    _field = field;
  }
  
  /**
   * Evaluate the expr as an object.
   *
   * @param env the page context
   */
  @Override
  public Object getValue(ELContext env)
    throws ELException
  {
    if (! (env instanceof ServletELContext)) {
      ELResolver elResolver = env.getELResolver();
      
      Object scope = elResolver.getValue(env, null, "initParam");
      
      return elResolver.getValue(env, scope, _field);
    }

    ServletELContext servletEnv = (ServletELContext) env;

    ServletContext webApp = servletEnv.getApplication();

    return webApp.getInitParameter(_field);
  }

  public String getExpressionString()
  {
    return "initParam['" + _field + "']";
  }
}