Imperfect C++ Practical Solutions for Real-Life Programming

Chapter 25. Fast, Non-intrusive String Concatenation

A well-known inefficiency in Java [Larm2000] is in string concatenation. The way around it is to ensure that the concatenation is done within a single statement, which facilitates a compiler optimization in which the successive arguments to the + operator are silently translated into calls to a hidden StringBuffer instance, resulting in a more efficient construction of the string from its constituent parts. Hence,

String s = s1 + " " + s2 + " " + s3;

is automatically converted to

StringBuffer  sb = new StringBuffer();
sb.append(s1);
sb.append(" ");
sb.append(s2);
sb.append(" ");
sb.append(s3);
String        s = sb.toString();

This results in significant increases in performance [Wils2003e] compared ...