Parameterized Strings in Java

Question

I find myself very frequently wanting to write reusable strings with parameter placeholders in them, almost exactly like what you'd find in an SQL PreparedStatement.

Here's an example

private static final String warning = "You requested ? but were assigned ? instead.";  public void addWarning(Element E, String requested, String actual){       warning.addParam(0, requested);      warning.addParam(1, actual);      e.setText(warning);      //warning.reset() or something, I haven't sorted that out yet. } 

Does something like this exist already in Java ? Or, is there a better way to address something like this ?

What I'm really asking: is this ideal ?

Answer 1

String.format()

Since Java 5, you can use String.format to parametrize Strings. Example:

String fs; fs = String.format("The value of the float " +                    "variable is %f, while " +                    "the value of the " +                     "integer variable is %d, " +                    " and the string is %s",                    floatVar, intVar, stringVar); 

See http://docs.oracle.com/javase/tutorial/java/data/strings.html

Alternatively, you could just create a wrapper for the String to do something more fancy.

MessageFormat

Per the comment by Max and answer by Affe, you can localize your parameterized String with the MessageFormat class.

Answer 2

You could use String.format. Something like:

String message = String.format("You requested %2$s but were assigned %1$s", "foo", "bar"); 

will generate

"You requested bar but were assigned foo"