How do I force-enclose a CodeModel expression in brackets?

I want to generate some very common code using Sun's CodeModel

while ((sbt = reader.readLine()) != null)
{

}

However when I write:

JWhileLoop whileJsonBuilder = block._while(JExpr
                            .ref("partJsonString").assign(JExpr.ref("reader"))
                            .ne(JExpr._null()));

I get

while (partJsonString = reader!= null) {
    stringBuilder.append(partJsonString);
}

Notice that the brackets are missing. How can I force brackets to appear in the code?

Unfortunately I was unable to find a preexisting way to add parenthesis. You can, however, extend JCodeModel to handle this by adding a special JExpression to render the paraenthesis:

public class ParensExpession extends JExpressionImpl{

    private JExpression expression;

    public ParensExpession(JExpression expression) {
        this.expression = expression;
    }

    @Override
    public void generate(JFormatter formatter) {
        formatter.p('(').g(expression).p(')');
    }
}

Incorporated into your code:

JWhileLoop whileJsonBuilder = block._while(
    new ParensExpession(
        JExpr.ref("partJsonString").assign(JExpr.ref("reader"))
    ).ne(JExpr._null()));

Gives:

while ((partJsonString = reader)!= null);