参数调用内的花括号。 >>这是什么意思？ |春季3和GWT

Question

question

When the code segment "new TextColumn(){...}, "MyObjectId");" executes then what does the code inside the outermost of pair curly braces represent? Does it represent an anonymous inner class instance of the TextColumn object? Does it represent the definition of the TextColumn object?

code

table.addColumn(new TextColumn<MyObjectProxy>() {
    Renderer<Integer> renderer = new AbstractRenderer<Integer>() {
        public String render(Integer obj) {
            return obj == null ? "" : String.valueOf(obj);
        }
    };
    @Override
    public String getValue(MyObjectProxy object) {
        return renderer.render(object.getMyObjectId());
    }
}, "MyObjectId");

if you are wondering the TextColumn is from the com.google.gwt.user.cellview.client.TextColumn package.

Answer 1

That's an anonymous inner class that extends TextColumn<MyObjectProxy> . In it, it has a field named renderer of type Renderer<Integer> that is initialized with an instance of an anonymous inner class that extends AbstractRenderer<Integer> . There is also an override of method getValue below that.

Answer 2

It simply defines an anonym class and creates an instance of it. This instance is passed as parameter to the method table.addColumn .

Answer 3

Yes, it's an anonymous class, corresponding to the TextColumn Object.

The getValue() method is overriden.