screen widget 本质是基于freemarker 的。 目前screen类型的view基本都是MacroScreenViewHandler.java 负责处理的。
MacroScreenViewHandler.java render 方法中首先通过配置文件加载了三个类库。如下
ScreenStringRenderer screenStringRenderer = new MacroScreenRenderer(UtilProperties.getPropertyValue("widget", getName() + ".name"), UtilProperties.getPropertyValue("widget", getName() + ".screenrenderer"));
FormStringRenderer formStringRenderer = new MacroFormRenderer(UtilProperties.getPropertyValue("widget", getName() + ".formrenderer"), request, response);
TreeStringRenderer treeStringRenderer = new MacroTreeRenderer(UtilProperties.getPropertyValue("widget", getName() + ".treerenderer"), writer);
正式render 页面前后，利用freemarker 编译了两个宏指令
screenStringRenderer.renderScreenBegin(writer, screens.getContext());
screens.render(page);
screenStringRenderer.renderScreenEnd(writer, screens.getContext());
public void renderScreenBegin(Appendable writer, Map<String, Object> context) throws IOException { executeMacro(writer, "renderScreenBegin", null); } public void renderScreenEnd(Appendable writer, Map<String, Object> context) throws IOException { executeMacro(writer, "renderScreenEnd", null); }
宏指令定义为
<#macro renderScreenBegin> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> </#macro> <#macro renderScreenEnd> </#macro>
screen widget 大概处理过程。获取screnn 第一个section ，解析处理action（预处理所需数据）condition，根据condition结果决定处理子widget是widget还是fail-widget 。子widget的处理过程和上层widget类似。如此深入。具体的没有嵌套的screen widget 可以使用上述freemarker 类库来编译成html。
