spring源碼（7）alias標籤的解析

<bean id="some" class="src.com.Some"/>
<alias name="some" alias="someJava,oneBean,twoBean"/>

protected void processAliasRegistration(Element ele) {
        //--獲取“name”、“alias”屬性
        /*
         *  <bean id="some" class="src.com.Some"/>
         *  <alias name="some" alias="someJava,oneBean,twoBean"/>
         */
        //獲取name屬性
        String name = ele.getAttribute(NAME_ATTRIBUTE);
        //獲取alias屬性
        String alias = ele.getAttribute(ALIAS_ATTRIBUTE);
        boolean valid = true;
        if (!StringUtils.hasText(name)) {
            getReaderContext().error("Name must not be empty", ele);
            valid = false;
        }
        if (!StringUtils.hasText(alias)) {
            getReaderContext().error("Alias must not be empty", ele);
            valid = false;
        }
        if (valid) {
            try {
                //註冊別名
                getReaderContext().getRegistry().registerAlias(name, alias);
            }
            catch (Exception ex) {
                getReaderContext().error("Failed to register alias '" + alias +
                        "' for bean with name '" + name + "'", ele, ex);
            }
            //通知監聽者
            getReaderContext().fireAliasRegistered(name, alias, extractSource(ele));
        }
    }