30 Jul
2008
30 Jul
'08
6:02 p.m.
Eliot, I read your answer and (like Colin probably) I didn't understand if you were speaking about immutable objects in Smalltalk, or of immutable strings (as in Java, where you have immutable java.lang.String objects and use java.lang.StringBuffer to obtain a restricted kind of mutability).So java strings are not really immutable but they don't provide a mutability API?
No, java strings are immutable (because they are in a final, i.e. not inheritable class, and don't provide a mutability API).
A java.lang.StringBuffer object is substantially a mutable, growable String even though it is 99% of the time used the same way as a Smalltalk WriteStream. But the StringBuffer is not polymorphic with Strings: sooner or later however you'll have to convert the StringBuffer to a String to pass it to methods expecting a java.lang.String.
Paolo