/*
    * 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 javax.faces.validator;
  
  import javax.el.ELException;
  import javax.el.MethodExpression;
  import javax.faces.application.FacesMessage;
  import javax.faces.component.StateHolder;
  import javax.faces.component.UIComponent;
  import javax.faces.context.FacesContext;
  
  /**
   * see Javadoc of <a href="http://java.sun.com/j2ee/javaserverfaces/1.2/docs/api/index.html">JSF Specification</a>
   *
   * @author Stan Silvert
   */
  public class MethodExpressionValidator implements Validator, StateHolder {
      
      private MethodExpression methodExpression;
      
      private boolean isTransient = false;
      
      /** Creates a new instance of MethodExpressionValidator */
      public MethodExpressionValidator() {
      }
      
      public MethodExpressionValidator(MethodExpression methodExpression) {
          if (methodExpression == null) throw new NullPointerException("methodExpression can not be null.");
          
          this.methodExpression = methodExpression;
      }
  
      public void validate(FacesContext context, UIComponent component, Object value) throws ValidatorException {
          Object[] params = new Object[3];
          params[0] = context;
          params[1] = component;
          params[2] = value;
          
          try {
              methodExpression.invoke(context.getELContext(), params);
          } 
          catch (ELException e) {
              Throwable cause = e.getCause();
              if (cause instanceof ValidatorException) {
                  throw (ValidatorException) cause;
              }
              else {
                  throw e;
              }
          }
      }
  
      public void restoreState(FacesContext context, Object state) {
          methodExpression = (MethodExpression)state;
      }
  
      public Object saveState(FacesContext context) {
          return methodExpression;
      }
  
      public void setTransient(boolean newTransientValue) {
          isTransient = newTransientValue;
      }
  
      public boolean isTransient() {
          return isTransient;
      }
      
  }