propertyutilsbean.java

一个很好实用的工作流OSWORKFLOW开发例子.有着非常优秀的灵活性.

   * thrown.
   *
   * @param bean Bean whose property is to be extracted
   * @param name <code>propertyname(key)</code> of the property value
   *             to be extracted
   * @throws IllegalAccessException    if the caller does not have
   *                                   access to the property accessor method
   * @throws InvocationTargetException if the property accessor method
   *                                   throws an exception
   * @throws NoSuchMethodException     if an accessor method for this
   *                                   propety cannot be found
   */
  public Object getMappedProperty(Object bean, String name) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException
  {

    if(bean == null)
    {
      throw new IllegalArgumentException("No bean specified");
    }
    if(name == null)
    {
      throw new IllegalArgumentException("No name specified");
    }

    // Identify the index of the requested individual property
    int delim = name.indexOf(PropertyUtils.MAPPED_DELIM);
    int delim2 = name.indexOf(PropertyUtils.MAPPED_DELIM2);
    if((delim < 0) || (delim2 <= delim))
    {
      throw new IllegalArgumentException("Invalid mapped property '" + name + "'");
    }

    // Isolate the name and the key
    String key = name.substring(delim + 1, delim2);
    name = name.substring(0, delim);

    // Request the specified indexed property value
    return (getMappedProperty(bean, name, key));

  }

  /**
   * Return the value of the specified mapped property of the specified
   * bean, with no type conversions.
   *
   * @param bean Bean whose property is to be extracted
   * @param name Mapped property name of the property value to be extracted
   * @param key  Key of the property value to be extracted
   * @throws IllegalAccessException    if the caller does not have
   *                                   access to the property accessor method
   * @throws InvocationTargetException if the property accessor method
   *                                   throws an exception
   * @throws NoSuchMethodException     if an accessor method for this
   *                                   propety cannot be found
   */
  public Object getMappedProperty(Object bean, String name, String key) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException
  {

    if(bean == null)
    {
      throw new IllegalArgumentException("No bean specified");
    }
    if(name == null)
    {
      throw new IllegalArgumentException("No name specified");
    }
    if(key == null)
    {
      throw new IllegalArgumentException("No key specified");
    }

    // Handle DynaBean instances specially
    Object result = null;

    // Retrieve the property descriptor for the specified property
    PropertyDescriptor descriptor = getPropertyDescriptor(bean, name);
    if(descriptor == null)
    {
      throw new NoSuchMethodException("Unknown property '" + name + "'");
    }

    if(descriptor instanceof MappedPropertyDescriptor)
    {
      // Call the keyed getter method if there is one
      Method readMethod = ((MappedPropertyDescriptor)descriptor).getMappedReadMethod();
      if(readMethod != null)
      {
        Object keyArray[] = new Object[1];
        keyArray[0] = key;
        result = invokeMethod(readMethod, bean, keyArray);
      }
      else
      {
        throw new NoSuchMethodException("Property '" + name + "' has no mapped getter method");
      }
    }
    else
    {
      /* means that the result has to be retrieved from a map */
      Method readMethod = descriptor.getReadMethod();
      if(readMethod != null)
      {
        Object invokeResult = invokeMethod(readMethod, bean, new Object[0]);
        /* test and fetch from the map */
        if(invokeResult instanceof java.util.Map)
        {
          result = ((java.util.Map)invokeResult).get(key);
        }
      }
      else
      {
        throw new NoSuchMethodException("Property '" + name + "' has no mapped getter method");
      }
    }
    return result;

  }

  /**
   * <p>Return the mapped property descriptors for this bean class.</p>
   * <p/>
   * <p><strong>FIXME</strong> - Does not work with DynaBeans.</p>
   *
   * @param beanClass Bean class to be introspected
   */
  public Map getMappedPropertyDescriptors(Class beanClass)
  {

    if(beanClass == null)
    {
      return null;
    }

    // Look up any cached descriptors for this bean class
    return (Map)mappedDescriptorsCache.get(beanClass);

  }

  /**
   * <p>Return the mapped property descriptors for this bean.</p>
   * <p/>
   * <p><strong>FIXME</strong> - Does not work with DynaBeans.</p>
   *
   * @param bean Bean to be introspected
   */
  public Map getMappedPropertyDescriptors(Object bean)
  {

    if(bean == null)
    {
      return null;
    }
    return (getMappedPropertyDescriptors(bean.getClass()));

  }

  /**
   * Return the value of the (possibly nested) property of the specified
   * name, for the specified bean, with no type conversions.
   *
   * @param bean Bean whose property is to be extracted
   * @param name Possibly nested name of the property to be extracted
   * @throws IllegalAccessException    if the caller does not have
   *                                   access to the property accessor method
   * @throws IllegalArgumentException  if <code>bean</code> or
   *                                   <code>name</code> is null
   * @throws IllegalArgumentException  if a nested reference to a
   *                                   property returns null
   * @throws InvocationTargetException if the property accessor method throws an exception
   * @throws NoSuchMethodException     if an accessor method for this
   *                                   propety cannot be found
   */
  public Object getNestedProperty(Object bean, String name) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException
  {

    if(bean == null)
    {
      throw new IllegalArgumentException("No bean specified");
    }
    if(name == null)
    {
      throw new IllegalArgumentException("No name specified");
    }

    int indexOfINDEXED_DELIM;
    int indexOfMAPPED_DELIM;
    int indexOfMAPPED_DELIM2;
    int indexOfNESTED_DELIM;
    while(true)
    {
      indexOfNESTED_DELIM = name.indexOf(PropertyUtils.NESTED_DELIM);
      indexOfMAPPED_DELIM = name.indexOf(PropertyUtils.MAPPED_DELIM);
      indexOfMAPPED_DELIM2 = name.indexOf(PropertyUtils.MAPPED_DELIM2);
      if(indexOfMAPPED_DELIM2 >= 0 && indexOfMAPPED_DELIM >= 0 && (indexOfNESTED_DELIM < 0 || indexOfNESTED_DELIM > indexOfMAPPED_DELIM))
      {
        indexOfNESTED_DELIM = name.indexOf(PropertyUtils.NESTED_DELIM, indexOfMAPPED_DELIM2);
      }
      else
      {
        indexOfNESTED_DELIM = name.indexOf(PropertyUtils.NESTED_DELIM);
      }
      if(indexOfNESTED_DELIM < 0)
      {
        break;
      }
      String next = name.substring(0, indexOfNESTED_DELIM);
      indexOfINDEXED_DELIM = next.indexOf(PropertyUtils.INDEXED_DELIM);
      indexOfMAPPED_DELIM = next.indexOf(PropertyUtils.MAPPED_DELIM);
      if(bean instanceof Map)
      {
        bean = ((Map)bean).get(next);
      }
      else if(indexOfMAPPED_DELIM >= 0)
      {
        bean = getMappedProperty(bean, next);
      }
      else if(indexOfINDEXED_DELIM >= 0)
      {
        bean = getIndexedProperty(bean, next);
      }
      else
      {
        bean = getSimpleProperty(bean, next);
      }
      if(bean == null)
      {
        throw new NullPointerException("Null property value for '" + name.substring(0, indexOfNESTED_DELIM) + "'");
      }
      name = name.substring(indexOfNESTED_DELIM + 1);
    }

    indexOfINDEXED_DELIM = name.indexOf(PropertyUtils.INDEXED_DELIM);
    indexOfMAPPED_DELIM = name.indexOf(PropertyUtils.MAPPED_DELIM);

    if(bean instanceof Map)
    {
      bean = ((Map)bean).get(name);
    }
    else if(indexOfMAPPED_DELIM >= 0)
    {
      bean = getMappedProperty(bean, name);
    }
    else if(indexOfINDEXED_DELIM >= 0)
    {
      bean = getIndexedProperty(bean, name);
    }
    else
    {
      bean = getSimpleProperty(bean, name);
    }
    return bean;

  }

  /**
   * Return the value of the specified property of the specified bean,
   * no matter which property reference format is used, with no
   * type conversions.
   *
   * @param bean Bean whose property is to be extracted
   * @param name Possibly indexed and/or nested name of the property
   *             to be extracted
   * @throws IllegalAccessException    if the caller does not have
   *                                   access to the property accessor method
   * @throws IllegalArgumentException  if <code>bean</code> or
   *                                   <code>name</code> is null
   * @throws InvocationTargetException if the property accessor method
   *                                   throws an exception
   * @throws NoSuchMethodException     if an accessor method for this
   *                                   propety cannot be found
   */
  public Object getProperty(Object bean, String name) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException
  {

    return (getNestedProperty(bean, name));

  }

  /**
   * <p>Retrieve the property descriptor for the specified property of the
   * specified bean, or return <code>null</code> if there is no such
   * descriptor.  This method resolves indexed and nested property
   * references in the same manner as other methods in this class, except
   * that if the last (or only) name element is indexed, the descriptor
   * for the last resolved property itself is returned.</p>
   * <p/>
   * <p><strong>FIXME</strong> - Does not work with DynaBeans.</p>
   *
   * @param bean Bean for which a property descriptor is requested
   * @param name Possibly indexed and/or nested name of the property for
   *             which a property descriptor is requested
   * @throws IllegalAccessException    if the caller does not have
   *                                   access to the property accessor method
   * @throws IllegalArgumentException  if <code>bean</code> or
   *                                   <code>name</code> is null
   * @throws IllegalArgumentException  if a nested reference to a
   *                                   property returns null
   * @throws InvocationTargetException if the property accessor method
   *                                   throws an exception
   * @throws NoSuchMethodException     if an accessor method for this
   *                                   propety cannot be found
   */
  public PropertyDescriptor getPropertyDescriptor(Object bean, String name) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException
  {

    if(bean == null)
    {
      throw new IllegalArgumentException("No bean specified");
    }
    if(name == null)
    {
      throw new IllegalArgumentException("No name specified");
    }

    // Resolve nested references
    while(true)
    {
      int period = findNextNestedIndex(name);
      if(period < 0)
      {
        break;
      }
      String next = name.substring(0, period);
      int indexOfINDEXED_DELIM = next.indexOf(PropertyUtils.INDEXED_DELIM);
      int indexOfMAPPED_DELIM = next.indexOf(PropertyUtils.MAPPED_DELIM);
      if(indexOfMAPPED_DELIM >= 0 && (indexOfINDEXED_DELIM < 0 || indexOfMAPPED_DELIM < indexOfINDEXED_DELIM))
      {
        bean = getMappedProperty(bean, next);
      }
      else
      {
        if(indexOfINDEXED_DELIM >= 0)
        {
          bean = getIndexedProperty(bean, next);
        }
        else
        {
          bean = getSimpleProperty(bean, next);
        }
      }
      if(bean == null)
      {
        throw new IllegalArgumentException("Null property value for '" + name.substring(0, period) + "'");
      }
      name = name.substring(period + 1);
    }

    // Remove any subscript from the final name value
    int left = name.indexOf(PropertyUtils.INDEXED_DELIM);
    if(left >= 0)
    {
      name = name.substring(0, left);
    }
    left = name.indexOf(PropertyUtils.MAPPED_DELIM);
    if(left >= 0)
    {
      name = name.substring(0, left);
    }

    // Look up and return this property from our cache
    // creating and adding it to the cache if not found.
    if((bean == null) || (name == null))
    {
      return (null);
    }

    PropertyDescriptor descriptors[] = getPropertyDescriptors(bean);
    if(descriptors != null)
    {

      for(int i = 0; i < descriptors.length; i++)
      {
        if(name.equals(descriptors[i].getName()))
          return (descriptors[i]);
      }
    }

    PropertyDescriptor result;
    Map mappedDescriptors = getMappedPropertyDescriptors(bean);
    if(mappedDescriptors == null)
    {
      mappedDescriptors = new HashMap();
      mappedDescriptorsCache.put(bean.getClass(), mappedDescriptors);
    }
    result = (PropertyDescriptor)mappedDescriptors.get(name);
    if(result == null)
    {
      // not found, try to create it
      try
      {
        result = new MappedPropertyDescriptor(name, bean.getClass());
      }
      catch(IntrospectionException ie)
      {
      }
      if(result != null)
      {
        mappedDescriptors.put(name, result);
      }
    }

    return result;

  }

  private int findNextNestedIndex(String expression)
  {
    // walk back from the end to the start
    // and find the first index that
    int bracketCount = 0;
    for(int i = 0, size = expression.length(); i < size; i++)
    {
      char at = expression.charAt(i);
      switch(at)
      {
        case PropertyUtils.NESTED_DELIM:
          if(bracketCount < 1)
          {
            return i;
          }
          break;

        case PropertyUtils.MAPPED_DELIM:
        case PropertyUtils.INDEXED_DELIM:
          // not bothered which
          ++bracketCount;
          break;

        case PropertyUtils.MAPPED_DELIM2:
        case PropertyUtils.INDEXED_DELIM2:
          // not bothered which
          --bracketCount;
          break;