具有Groovy’with’闭包的重复try-catch块？

发布时间：2020-12-14 16:24:35 所属栏目：大数据来源：网络整理

导读：我有以下Groovy类： @Slf4jclass WidgetService { WidgetDao widgetDao = new WidgetDao() createWidget(String name,int type) { try { widgetDao.createWidget(name,type) } catch(WidgetException wexc) { log.error(wexc) int x = doFizz() long y = doB

我有以下Groovy类：

@Slf4j
class WidgetService {
    WidgetDao widgetDao = new WidgetDao()

    createWidget(String name,int type) {
        try {
            widgetDao.createWidget(name,type)
        } catch(WidgetException wexc) {
            log.error(wexc)
            int x = doFizz()
            long y = doBuzz(x)
            determineHowToHandle(y)
        }
    }

    Widget getWidgetById(Long id) {
        try {
            widgetDao.getWidgetById(id)
        } catch(WidgetException wexc) {
            log.error(wexc)
            int x = doFizz()
            long y = doBuzz(x)
            determineHowToHandle(y)
        }
    }

    Widget getWidgetByName(String name) {
        try {
            widgetDao.getWidgetByName(name)
        } catch(WidgetException wexc) {
            log.error(wexc)
            int x = doFizz()
            long y = doBuzz(x)
            determineHowToHandle(y)
        }
    }

    def deleteWidget(Widget w) {
        try {
            widgetDao.deleteWidget(w)
        } catch(WidgetException wexc) {
            log.error(wexc)
            int x = doFizz()
            long y = doBuzz(x)
            determineHowToHandle(y)
        }
    }

    ...dozens of more methods with *exact* same catch block
}

正如您所看到的,我的try-catch块中有很多重复的样板代码.如果我可以定义一个闭包或某种基于AOP的处理程序,只需将widgetDao感兴趣的方法作为lambda或类似的东西传递给闭包/处理程序,那就太好了：

def createWidgetClosure = { it =>
    widgetDao.createWidget(it.name,it.type)
}

def getWidgetByIdClosure = { it =>
    widgetDao.getWidgetById(it.id)
}

def tryCatchClosure = { closure =>
    try {
        closure()
    } catch(WidgetException wexc) {
        log.error(wexc)
        int x = doFizz()
        long y = doBuzz(x)
        determineHowToHandle(y)
    }
}

这样我的`WidgetService就可以看起来像这样：

@Slf4j
class WidgetService {
    WidgetDao widgetDao = new WidgetDao()

    createWidget(String name,int type) {
        tryCatchClosure(createWidgetClosure())
    }

    Widget getWidgetById(Long id) {
        tryCatchClosure(getWidgetByIdClosure())
    }

    ...dozens of more methods with *exact* same catch block
}

这可能吗？如果是这样,怎么样？

解决方法

您可以使用tryCatchClosure,现在只需执行以下操作.你甚至可以让tryCatchClosure成为一个以Closure作为参数的方法.

class WidgetService {
    WidgetDao widgetDao = new WidgetDao()

    def tryCatchClosure(Closure closure) {
        try {
            closure()
        } catch(WidgetException wexc) {
            log.error(wexc)
            int x = doFizz()
            long y = doBuzz(x)
            determineHowToHandle(y)
        }
    }

    createWidget(String name,int type) {
        tryCatchClosure {
            widgetDao.createWidget(name,type)
        } 
    }

    Widget getWidgetById(Long id) {
        tryCatchClosure {
            widgetDao.getWidgetById(id)
        }
    }

    Widget getWidgetByName(String name) {
        tryCatchClosure {
            widgetDao.getWidgetByName(name)
        }
    }

    def deleteWidget(Widget w) {
        tryCatchClosure {
            widgetDao.deleteWidget(w)
        }
    }

    // ...dozens of more methods with *exact* same catch block
}

或者您也可以通过覆盖其metaClass上的invokeMethod方法并处理异常(try / catch)来拦截WidgetDao上的每个方法调用. Similar to this.

（编辑：李大同）

【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容!