EditHint: Move stuff on this topic from ConstCorrectness to here.
I appreciate ConstCorrectness enormously and miss it sorely in JavaLanguage. :-(
Some languages have RunTime constantness, with freeze and thaw. Do they allow thaw when running in a secure mode?
Given...
Object nonConst; Object const Const; Object const & constRef = nonConst; nonConst.foo(); // <-- calls foo() (non-const) if available Const.foo(); // <-- must call foo() const constRef.foo(); // <-- must call foo() const...note that constancy is a form of encapsulation. Both the Const object and the constRef make their Object more encapsulated - meaning potentially safer and more robust - than the non-constant versions. So "const-correct" code generally extends more usages to constant things than to changeable things.
More literally:
interface FooConst?{ int readX(); int readY(); } abstract class Foo implements FooConst?{ abstract public int readX(); abstract public int readY(); abstract public int writeX(int value); abstract public int writeY(int value); }Methods that want a "const Foo" parameter need only declare a FooConst? as their argument.