View Javadoc

    1   /*
    2    * Licensed to the Apache Software Foundation (ASF) under one
    3    * or more contributor license agreements.  See the NOTICE file
    4    * distributed with this work for additional information
    5    * regarding copyright ownership.  The ASF licenses this file
    6    * to you under the Apache License, Version 2.0 (the
    7    * "License"); you may not use this file except in compliance
    8    * with the License.  You may obtain a copy of the License at
    9    *
    10   *   http://www.apache.org/licenses/LICENSE-2.0
    11   *
    12   * Unless required by applicable law or agreed to in writing,
    13   * software distributed under the License is distributed on an
    14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    15   * KIND, either express or implied.  See the License for the
    16   * specific language governing permissions and limitations
    17   * under the License.
    18   */
    19
    20  package org.apache.myfaces.orchestra.viewController;
    21
    22  import org.apache.myfaces.orchestra.lib.OrchestraException;
    23
    24  import java.lang.reflect.InvocationTargetException;
    25  import java.lang.reflect.Method;
    26
    27  /**
    28   * Invokes ViewController events using reflection.
    29   * <p>
    30   * If the target bean has a method with any of the following signatures then it
    31   * receives the appropriate callback:
    32   * <ul>
    33   * <li>public void initView()</li>
    34   * <li>public void preProcess()</li>
    35   * <li>public void preRenderView()</li>
    36   * </ul>
    37   * <p>
    38   * Note that each method here returns false if the target bean does not
    39   * have a method with an appropriate signature; this allows this executor to
    40   * be "chained" with others.
    41   */
    42  public class ReflectiveViewControllerExecutor extends AbstractViewControllerExecutor
    43  {
    44      /**
    45       * Helper method to find the method which should get invoked.
    46       */
    47      protected boolean invokeOnViewController(Object bean, String methodName)
    48      {
    49          try
    50          {
    51              Method method = bean.getClass().getMethod(methodName, (Class[]) null); // NON-NLS
    52              method.invoke(bean, (Object[]) null);
    53          }
    54          catch (NoSuchMethodException e)
    55          {
    56              return false;
    57          }
    58          catch (IllegalAccessException e)
    59          {
    60              throw new OrchestraException(e);
    61          }
    62          catch (InvocationTargetException e)
    63          {
    64              throw new OrchestraException(e);
    65          }
    66
    67          return true;
    68      }
    69
    70      /* the ViewControllerExecutor interface */
    71      public boolean invokeInitView(String beanName, Object bean)
    72      {
    73          return invokeOnViewController(bean, "initView");
    74      }
    75
    76      public boolean invokePreRenderView(String beanName, Object bean)
    77      {
    78          return invokeOnViewController(bean, "preRenderView");
    79      }
    80
    81      public boolean invokePreProcess(String beanName, Object bean)
    82      {
    83          return invokeOnViewController(bean, "preProcess");
    84      }
    85  }