/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.myfaces.tobago.util;

import org.apache.myfaces.tobago.context.ClientProperties;

import javax.el.ELContext;
import javax.faces.context.FacesContext;

public final class VariableResolverUtils {

  private VariableResolverUtils() {
    // utils class
  }

  /**
   * Returns the requested object configured in the faces-config or from library.
   */
  public static Object resolveVariable(final FacesContext context, final String variable) {
    final ELContext elContext = context.getELContext();
    return elContext.getELResolver().getValue(elContext, null, variable);
  }

  /**
   * Returns the ClientProperties object configured in the faces-config.
   *
   * @deprecated Since 2.0.0. Please use
   * {@link org.apache.myfaces.tobago.context.ClientProperties#getInstance(javax.faces.context.FacesContext)}
   */
  @Deprecated
  public static ClientProperties resolveClientProperties(final FacesContext facesContext) {
    return ClientProperties.getInstance(facesContext);
  }
  
  /**
   * Clears the value of the variable.
   * Useful for cleaning up e.g. a session or application variable
   * to save memory without the knowledge of the scope.
   * Also useful to enforce a new creation of a managed-bean.
   */
  public static void clearVariable(final FacesContext context, final String variable) {
    final ELContext elContext = context.getELContext();
    elContext.getELResolver().setValue(elContext, null, variable, null);
  }
}
