不推荐使用richfaces javax.faces.el.MethodBinding替换使用
我发现这段代码的工作原理是我可以通过编程方式创建一个richfaces下拉菜单。 但有些代码已被弃用。 谁能告诉我要放入什么而不是弃用的电话?
谢谢
public HtmlDropDownMenu getMyMenu() { HtmlDropDownMenu menu = new HtmlDropDownMenu(); menu.setValue( "Node Select" ); HtmlMenuItem menuItem = new HtmlMenuItem(); // TODO programmatically pass from getNodes into a String[] rather than an ArrayList of SelectItems String subOption = "myBox"; menuItem.setValue( subOption ); Application app = FacesContext.getCurrentInstance().getApplication(); javax.faces.el.MethodBinding mb = app.createMethodBinding( "#{PrismBacking.onItemClick}", new Class[] { ActionEvent.class } ); menuItem.setActionListener( mb ); menu.getChildren().add( menuItem ); return( menu ); } public void onItemClick( ActionEvent event ) { Object obj = event.getSource(); if( obj instanceof HtmlMenuItem ) { HtmlMenuItem item = (HtmlMenuItem)obj; if( item != null ) { lastItem = item.getValue().toString(); } } }
不推荐使用的代码行是:
javax.faces.el.MethodBinding mb = app.createMethodBinding( "#{PrismBacking.onItemClick}", new Class[] { ActionEvent.class } ); menuItem.setActionListener( mb );
javadocs清楚地说明了这一点:
Application.createMethodBinding
不推荐 。 这已被替换为调用getExpressionFactory()然后调用ExpressionFactory.createMethodExpression(javax.el.ELContext,java.lang.String,java.lang.Class,java.lang.Class []) 。
以下是如何使用它:
MethodExpression methodExpression = application.getExpressionFactory().createMethodExpression( FacesContext.getCurrentInstance().getELContext(), "#{PrismBacking.onItemClick}", null, new Class[] { ActionEvent.class }); menuItem.setActionExpression(methodExpression);
像往常一样,所有弃用确实只是在API文档中描述,包括有关替换的详细信息。
要有一个清晰的概述,这里有前JSF 1.2和后JSF 1.2方法动态创建Action和ActionListener:
在JSF 1.0 / 1.1中创建Action绑定:
MethodBinding action = FacesContext.getCurrentInstance().getApplication() .createMethodBinding("#{bean.action}", new Class[0]); uiCommandComponent.setAction(action);
在JSF 1.0 / 1.1中创建ActionListener绑定:
MethodBinding actionListener = FacesContext.getCurrentInstance().getApplication() .createMethodBinding("#{bean.actionListener}", new Class[] {ActionEvent.class}); uiCommandComponent.setActionListener(actionListener);
在JSF 1.2或更新版本中创建Action表达式:
FacesContext context = FacesContext.getCurrentInstance(); MethodExpression action = context.getApplication().getExpressionFactory() .createMethodExpression(context.getELContext(), "#{bean.action}", String.class, new Class[0]); uiCommandComponent.setActionExpression(action);
在JSF 1.2或更高版本中创建ActionListener表达式:
FacesContext context = FacesContext.getCurrentInstance(); MethodExpression actionListener = context.getApplication().getExpressionFactory() .createMethodExpression(context.getELContext(), "#{bean.actionListener}", null, new Class[] {ActionEvent.class}); uiCommandComponent.addActionListener(new MethodExpressionActionListener(actionListener));
为了避免大量的样板代码,你可以很好地将它包装在辅助方法中(如果需要在辅助/实用程序类中),例如:
public static MethodExpression createAction(String actionExpression, Class> returnType) { FacesContext context = FacesContext.getCurrentInstance(); return context.getApplication().getExpressionFactory() .createMethodExpression(context.getELContext(), actionExpression, returnType, new Class[0]); } public static MethodExpressionActionListener createActionListener(String actionListenerExpression) { FacesContext context = FacesContext.getCurrentInstance(); return new MethodExpressionActionListener(context.getApplication().getExpressionFactory() .createMethodExpression(context.getELContext(), actionListenerExpression, null, new Class[] {ActionEvent.class})); }
所以你可以按如下方式使用它:
uiCommandComponent.setActionExpression(createAction("#{bean.action}", String.class); uiCommandComponent.addActionListener(createActionListener("#{bean.actionListener}");
替换机制在JEE5 API(JSF的一部分)中有详细说明:
- Application.createMethodBinding
- Action.setActionListener