/* * Copyright (c) 2002-2012 Alibaba Group Holding Limited. * All rights reserved. * * Licensed 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 com.alibaba.toolkit.util.enumeration; import com.alibaba.toolkit.util.typeconvert.ConvertChain; import com.alibaba.toolkit.util.typeconvert.ConvertFailedException; import com.alibaba.toolkit.util.typeconvert.Converter; /** * 将对象转换成<code>Enum</code>. * <ul> * <li>如果对象已经是<code>targetType</code>了, 直接返回.</li> * <li>如果对象是字符串, 则试着把它转换成字符串名称所代表的<code>Enum</code>. 如果成功, 则返回.</li> * <li>试着将对象转换成<code>Enum.getUnderlyingClass</code>类型, 如果成功, 则返回对应的 * <code>Enum</code>.</li> * <li>如果有默认值, 则抛出带默认值的<code>ConvertFailedException</code></li> * <li>否则, 把对象传递给下一个<code>Converter</code>处理.</li> * </ul> * * @author Michael Zhou * @version $Id: EnumConverter.java,v 1.1 2003/07/03 07:26:20 baobao Exp $ */ public class EnumConverter implements Converter { public Object convert(Object value, ConvertChain chain) { Class targetType = chain.getTargetType(); if (targetType.isInstance(value)) { return value; } if (value instanceof String) { Enum enumObj = Enum.getEnumByName(targetType, ((String) value).trim()); if (enumObj != null) { return enumObj; } } Enum enumObj = null; try { Object enumValue = chain.getConvertManager().asTypeWithoutDefaultValue(Enum.getUnderlyingClass(targetType), value); enumObj = Enum.getEnumByValue(targetType, enumValue); } catch (ConvertFailedException e) { if (e.isDefaultValueSet()) { enumObj = Enum.getEnumByValue(targetType, e.getDefaultValue()); if (enumObj != null) { throw new ConvertFailedException(e).setDefaultValue(enumObj); } } return chain.convert(value); } if (enumObj == null) { throw new ConvertFailedException(); } return enumObj; } }