/*
* 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.citrus.service.form.support;
import static com.alibaba.citrus.util.Assert.*;
import static com.alibaba.citrus.util.StringUtil.*;
import com.alibaba.citrus.expr.Expression;
import com.alibaba.citrus.expr.ExpressionContext;
import com.alibaba.citrus.expr.ExpressionFactory;
import com.alibaba.citrus.expr.ExpressionParseException;
import com.alibaba.citrus.expr.composite.CompositeExpressionFactory;
import com.alibaba.citrus.service.form.Validator;
import com.alibaba.citrus.service.form.configuration.FieldConfig;
import com.alibaba.citrus.service.form.configuration.FormConfig;
import com.alibaba.citrus.service.form.configuration.GroupConfig;
import com.alibaba.citrus.springext.support.BeanSupport;
import com.alibaba.citrus.util.ObjectUtil;
import com.alibaba.citrus.util.StringEscapeUtil;
import com.alibaba.citrus.util.i18n.LocaleUtil;
import org.springframework.context.MessageSource;
import org.springframework.context.MessageSourceAware;
import org.springframework.context.NoSuchMessageException;
/**
* 抽象的<code>Validator</code>实现。
*
* @author Michael Zhou
*/
public abstract class AbstractValidator extends BeanSupport implements Validator, MessageSourceAware {
protected static final ExpressionFactory EXPRESSION_FACTORY = new CompositeExpressionFactory();
private String id;
private String messageCode;
private Message message;
private MessageSource messageSource;
public void setMessageSource(MessageSource messageSource) {
this.messageSource = messageSource;
}
/**
* 是否需要检查message值？
* <p>
* 如果是，则message未指定时将报错。
* </p>
*/
protected boolean requiresMessage() {
return true;
}
/** 当GroupConfig被初始化完成以后被调用，此时可取得同组中其它的fields。 */
public void init(FieldConfig fieldConfig) throws Exception {
if (requiresMessage()) {
boolean hasMessage = false;
// 1. 从messageSource中查找
if (id != null && messageSource != null) {
GroupConfig groupConfig = fieldConfig.getGroupConfig();
FormConfig formConfig = groupConfig.getFormConfig();
// form.groupName.fieldName.validatorId
messageCode = formConfig.getMessageCodePrefix() + groupConfig.getName() + "." + fieldConfig.getName()
+ "." + id;
hasMessage = getMessageFromMessageSource() != null;
}
// 2. 如果messageSource中找不到，则validator必须设置message
if (!hasMessage) {
assertNotNull(message, "no message");
message.compile();
}
}
}
private String getMessageFromMessageSource() {
try {
return messageSource.getMessage(messageCode, null, LocaleUtil.getContext().getLocale());
} catch (NoSuchMessageException e) {
return null;
}
}
/** 取得validator的ID，通过该ID可以找到指定的validator。 */
public String getId() {
return id == null ? getBeanName() : id;
}
/** 设置validator的ID，通过该ID可以找到指定的validator。 */
public void setId(String id) {
this.id = trimToNull(id);
}
/** 取得出错信息。 */
public final String getMessage(Context context) {
// 首先，假如message已经被设置，则直接返回。
// 例如all-of-validator就会设置这个message。
String result = trimToNull(context.getMessage());
if (result == null) {
// 然后，试着查找message source（仅当id存在）
Message message = this.message;
if (messageCode != null && messageSource != null) {
String messageFromMessageSource = getMessageFromMessageSource();
if (messageFromMessageSource != null) {
message = new Message(messageFromMessageSource);
message.compile();
}
}
// 渲染message
if (message != null) {
result = message.getMessageString(context.getMessageContext());
}
}
return result;
}
/** 设置出错信息。 */
public void setMessage(String message) {
this.message = new Message(message);
}
/** 生成副本。 */
@Override
public Validator clone() {
try {
return (Validator) super.clone();
} catch (CloneNotSupportedException e) {
return null; // 不可能发生！
}
}
/** 代表一个message表达式。 */
protected static class Message implements Cloneable {
private String message;
private Expression messageExpression;
public Message(String message) {
this.message = trimToNull(message);
}
/** 编译表达式。 */
public void compile() {
assertNotNull(message, "message");
try {
messageExpression = EXPRESSION_FACTORY.createExpression(message);
} catch (ExpressionParseException e) {
throw new IllegalArgumentException("Invalid message for validator " + getClass().getSimpleName()
+ ": \"" + StringEscapeUtil.escapeJava(message) + "\"");
}
}
/** 取得出错信息。 */
public String getMessageString(ExpressionContext context) {
return ObjectUtil.toString(messageExpression.evaluate(context), "");
}
@Override
public String toString() {
return "ValidatorMessage[" + message + "]";
}
}
}