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    1   /*
    2    * Copyright 2000-2002,2004 The Apache Software Foundation.
    3    *
    4    * Licensed under the Apache License, Version 2.0 (the "License");
    5    * you may not use this file except in compliance with the License.
    6    * You may obtain a copy of the License at
    7    *
    8    *      http://www.apache.org/licenses/LICENSE-2.0
    9    *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS,
    12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13   * See the License for the specific language governing permissions and
    14   * limitations under the License.
    15   */
    16  package org.apache.commons.jexl.util;
    17
    18  import java.lang.reflect.InvocationTargetException;
    19
    20  import org.apache.commons.jexl.util.introspection.Introspector;
    21  import org.apache.commons.logging.Log;
    22
    23  /***
    24   * Returned the value of object property when executed.
    25   */
    26  public class PropertyExecutor extends AbstractExecutor
    27  {
    28      protected Introspector introspector = null;
    29
    30      protected String methodUsed = null;
    31
    32      public PropertyExecutor(Log r, Introspector ispctr,
    33                              Class clazz, String property)
    34      {
    35          rlog = r;
    36          introspector = ispctr;
    37
    38          discover(clazz, property);
    39      }
    40
    41      protected void discover(Class clazz, String property)
    42      {
    43          /*
    44           *  this is gross and linear, but it keeps it straightforward.
    45           */
    46
    47          try
    48          {
    49              char c;
    50              StringBuffer sb;
    51
    52              Object[] params = {  };
    53
    54              /*
    55               *  start with get<property>
    56               *  this leaves the property name
    57               *  as is...
    58               */
    59              sb = new StringBuffer("get");
    60              sb.append(property);
    61
    62              methodUsed = sb.toString();
    63
    64              method = introspector.getMethod(clazz, methodUsed, params);
    65
    66              if (method != null)
    67                  return;
    68
    69              /*
    70               *  now the convenience, flip the 1st character
    71               */
    72
    73              sb = new StringBuffer("get");
    74              sb.append(property);
    75
    76              c = sb.charAt(3);
    77
    78              if (Character.isLowerCase(c))
    79              {
    80                  sb.setCharAt(3, Character.toUpperCase(c));
    81              }
    82              else
    83              {
    84                  sb.setCharAt(3, Character.toLowerCase(c));
    85              }
    86
    87              methodUsed = sb.toString();
    88              method = introspector.getMethod(clazz, methodUsed, params);
    89
    90              if (method != null)
    91                  return;
    92
    93          }
    94          catch(Exception e)
    95          {
    96              rlog.error("PROGRAMMER ERROR : PropertyExector() : " + e );
    97          }
    98      }
    99
    100
    101     /***
    102      * Execute method against context.
    103      */
    104     public Object execute(Object o)
    105         throws IllegalAccessException,  InvocationTargetException
    106     {
    107         if (method == null)
    108             return null;
    109
    110         return method.invoke(o, null);
    111     }
    112 }
    113
    114