Android : java syntax of addTextChangedListener(new TextWatcher())

i have a newbie question. Can someone explain what type of java syntax is in code like this. I've googled and but I dont seem to understand how is this an implementation of TextWatcher in anonymus class, (or something like that). All implementations I've seen so far had a keyword implements in a class definiton but this one does not. Any explanations are welcome (I know what this code does and how do I use it, the understanding of syntax is my problem.) If you could rewrite it in a equivalent way would also be great. Thanks

mObjectOfEditText.addTextChangedListener(new TextWatcher() {
                public void onTextChanged(parameters) {}

            public void beforeTextChanged(parameters) {}

            public void afterTextChanged(parameters) {}
        });