beanutilsbean.java

APACHE 公司出的java bean 工具包

                }
                if (getPropertyUtils().isReadable(orig, name) &&
                    getPropertyUtils().isWriteable(dest, name)) {
                    try {
                        Object value =
                            getPropertyUtils().getSimpleProperty(orig, name);
                        copyProperty(dest, name, value);
                    } catch (NoSuchMethodException e) {
                        // Should not happen
                    }
                }
            }
        }

    }


    /**
     * <p>Copy the specified property value to the specified destination bean,
     * performing any type conversion that is required.  If the specified
     * bean does not have a property of the specified name, or the property
     * is read only on the destination bean, return without
     * doing anything.  If you have custom destination property types, register
     * {@link Converter}s for them by calling the <code>register()</code>
     * method of {@link ConvertUtils}.</p>
     *
     * <p><strong>IMPLEMENTATION RESTRICTIONS</strong>:</p>
     * <ul>
     * <li>Does not support destination properties that are indexed,
     *     but only an indexed setter (as opposed to an array setter)
     *     is available.</li>
     * <li>Does not support destination properties that are mapped,
     *     but only a keyed setter (as opposed to a Map setter)
     *     is available.</li>
     * <li>The desired property type of a mapped setter cannot be
     *     determined (since Maps support any data type), so no conversion
     *     will be performed.</li>
     * </ul>
     *
     * @param bean Bean on which setting is to be performed
     * @param name Property name (can be nested/indexed/mapped/combo)
     * @param value Value to be set
     *
     * @exception IllegalAccessException if the caller does not have
     *  access to the property accessor method
     * @exception InvocationTargetException if the property accessor method
     *  throws an exception
     */
    public void copyProperty(Object bean, String name, Object value)
        throws IllegalAccessException, InvocationTargetException {

        // Trace logging (if enabled)
        if (log.isTraceEnabled()) {
            StringBuffer sb = new StringBuffer("  copyProperty(");
            sb.append(bean);
            sb.append(", ");
            sb.append(name);
            sb.append(", ");
            if (value == null) {
                sb.append("<NULL>");
            } else if (value instanceof String) {
                sb.append((String) value);
            } else if (value instanceof String[]) {
                String[] values = (String[]) value;
                sb.append('[');
                for (int i = 0; i < values.length; i++) {
                    if (i > 0) {
                        sb.append(',');
                    }
                    sb.append(values[i]);
                }
                sb.append(']');
            } else {
                sb.append(value.toString());
            }
            sb.append(')');
            log.trace(sb.toString());
        }

        // Resolve any nested expression to get the actual target bean
        Object target = bean;
        Resolver resolver = getPropertyUtils().getResolver();
        while (resolver.hasNested(name)) {
            try {
                target = getPropertyUtils().getProperty(target, resolver.next(name));
                name = resolver.remove(name);
            } catch (NoSuchMethodException e) {
                return; // Skip this property setter
            }
        }
        if (log.isTraceEnabled()) {
            log.trace("    Target bean = " + target);
            log.trace("    Target name = " + name);
        }

        // Declare local variables we will require
        String propName = resolver.getProperty(name); // Simple name of target property
        Class type = null;                            // Java type of target property
        int index  = resolver.getIndex(name);         // Indexed subscript value (if any)
        String key = resolver.getKey(name);           // Mapped key value (if any)

        // Calculate the target property type
        if (target instanceof DynaBean) {
            DynaClass dynaClass = ((DynaBean) target).getDynaClass();
            DynaProperty dynaProperty = dynaClass.getDynaProperty(propName);
            if (dynaProperty == null) {
                return; // Skip this property setter
            }
            type = dynaProperty.getType();
        } else {
            PropertyDescriptor descriptor = null;
            try {
                descriptor =
                    getPropertyUtils().getPropertyDescriptor(target, name);
                if (descriptor == null) {
                    return; // Skip this property setter
                }
            } catch (NoSuchMethodException e) {
                return; // Skip this property setter
            }
            type = descriptor.getPropertyType();
            if (type == null) {
                // Most likely an indexed setter on a POJB only
                if (log.isTraceEnabled()) {
                    log.trace("    target type for property '" +
                              propName + "' is null, so skipping ths setter");
                }
                return;
            }
        }
        if (log.isTraceEnabled()) {
            log.trace("    target propName=" + propName + ", type=" +
                      type + ", index=" + index + ", key=" + key);
        }

        // Convert the specified value to the required type and store it
        if (index >= 0) {                    // Destination must be indexed
            value = convert(value, type.getComponentType());
            try {
                getPropertyUtils().setIndexedProperty(target, propName,
                                                 index, value);
            } catch (NoSuchMethodException e) {
                throw new InvocationTargetException
                    (e, "Cannot set " + propName);
            }
        } else if (key != null) {            // Destination must be mapped
            // Maps do not know what the preferred data type is,
            // so perform no conversions at all
            // FIXME - should we create or support a TypedMap?
            try {
                getPropertyUtils().setMappedProperty(target, propName,
                                                key, value);
            } catch (NoSuchMethodException e) {
                throw new InvocationTargetException
                    (e, "Cannot set " + propName);
            }
        } else {                             // Destination must be simple
            value = convert(value, type);
            try {
                getPropertyUtils().setSimpleProperty(target, propName, value);
            } catch (NoSuchMethodException e) {
                throw new InvocationTargetException
                    (e, "Cannot set " + propName);
            }
        }

    }


    /**
     * <p>Return the entire set of properties for which the specified bean
     * provides a read method. This map contains the to <code>String</code>
     * converted property values for all properties for which a read method
     * is provided (i.e. where the getReadMethod() returns non-null).</p>
     *
     * <p>This map can be fed back to a call to
     * <code>BeanUtils.populate()</code> to reconsitute the same set of
     * properties, modulo differences for read-only and write-only
     * properties, but only if there are no indexed properties.</p>
     *
     * <p><strong>Warning:</strong> if any of the bean property implementations
     * contain (directly or indirectly) a call to this method then 
     * a stack overflow may result. For example:
     * <code><pre>
     * class MyBean
     * {
     *    public Map getParameterMap()
     *    {
     *         BeanUtils.describe(this);
     *    }
     * }
     * </pre></code>
     * will result in an infinite regression when <code>getParametersMap</code>
     * is called. It is recommended that such methods are given alternative
     * names (for example, <code>parametersMap</code>).
     * </p>
     * @param bean Bean whose properties are to be extracted
     * @return Map of property descriptors
     *
     * @exception IllegalAccessException if the caller does not have
     *  access to the property accessor method
     * @exception InvocationTargetException if the property accessor method
     *  throws an exception
     * @exception NoSuchMethodException if an accessor method for this
     *  property cannot be found
     */
    public Map describe(Object bean)
            throws IllegalAccessException, InvocationTargetException,
            NoSuchMethodException {

        if (bean == null) {
        //            return (Collections.EMPTY_MAP);
            return (new java.util.HashMap());
        }
        
        if (log.isDebugEnabled()) {
            log.debug("Describing bean: " + bean.getClass().getName());
        }
            
        Map description = new HashMap();
        if (bean instanceof DynaBean) {
            DynaProperty[] descriptors =
                ((DynaBean) bean).getDynaClass().getDynaProperties();
            for (int i = 0; i < descriptors.length; i++) {
                String name = descriptors[i].getName();
                description.put(name, getProperty(bean, name));
            }
        } else {
            PropertyDescriptor[] descriptors =
                getPropertyUtils().getPropertyDescriptors(bean);
            for (int i = 0; i < descriptors.length; i++) {
                String name = descriptors[i].getName();
                if (getPropertyUtils().getReadMethod(descriptors[i]) != null) {
                    description.put(name, getProperty(bean, name));
                }
            }
        }
        return (description);

    }


    /**
     * Return the value of the specified array property of the specified
     * bean, as a String array.
     *
     * @param bean Bean whose property is to be extracted
     * @param name Name of the property to be extracted
     * @return The array property value
     *
     * @exception IllegalAccessException if the caller does not have
     *  access to the property accessor method
     * @exception InvocationTargetException if the property accessor method
     *  throws an exception
     * @exception NoSuchMethodException if an accessor method for this
     *  property cannot be found
     */
    public String[] getArrayProperty(Object bean, String name)
            throws IllegalAccessException, InvocationTargetException,
            NoSuchMethodException {

        Object value = getPropertyUtils().getProperty(bean, name);
        if (value == null) {
            return (null);
        } else if (value instanceof Collection) {
            ArrayList values = new ArrayList();
            Iterator items = ((Collection) value).iterator();
            while (items.hasNext()) {
                Object item = items.next();
                if (item == null) {
                    values.add((String) null);
                } else {
                    // convert to string using convert utils
                    values.add(getConvertUtils().convert(item));
                }
            }
            return ((String[]) values.toArray(new String[values.size()]));
        } else if (value.getClass().isArray()) {
            int n = Array.getLength(value);