@DefaultTextFormat(Complex.Cartesian.class) 
 public class Complex {
 public String toString() { // Uses the default format unless locally overridden.
 return TextContext.toString(this);
 }
 public static Complex valueOf(CharSequence csq) {
 return TextContext.parse(csq, Complex.class);
 }
 public static class Cartesian extends TextFormat<Complex> { ... }
 public static class Polar extends TextFormat<Complex> { ... }
 }
 ...
 TextContext ctx = TextContext.enter(); // Enters a local textual context.
 try {
 ctx.setFormat(Complex.class, new Complex.Polar()); // Configure the local context.
 System.out.println(complexMatrix); // Displays complex numbers in polar coordinates.
 } finally {
 ctx.exit(); // Exits local context (reverts to previous Cartesian format).
 }