Doubt on page 547 HFSJ

[ankit kumar]

out.print(String.format(ATTR_TEMPLATE, “name”, this.name));
out.print(String.format(ATTR_TEMPLATE, “size”, this.size));

private static final String ATTR_TEMPLATE = “%s=’%s’ “;
private static final String OPTION_TEMPLATE= “ <option value=’%1$s’> %1$s </option>”;



but according to String API format function can,t take (String, String, String)

can anybody tell me what is going on ??

thanks in advance..

[Jonathan Elkharrat]

this is the format method signature:
format(String s, Object... args)

which mean the first argumet is a String
and a random number of Object argument
that are to be formmated in the String.

for example:
String name="Jonathan";
format("my name is %s",this.name); //print "my name is Jonathan"

the number of var-args (u did SCJP5, didn't you?) is unknown
till runtime.
since the format Strings (the 2 final Strings) have 2 arguments,
you need to send 2 Object (Strings in this case) to put there...

http://java.sun.com/j2se/1.5.0/docs/api/java/util/Formatter.html

[ankit kumar]

ya this is correct that String.format takes argument that you have mentioned
but what I have posted is mentioned in the book . to run that code what i have to do .

[Jonathan Elkharrat]

if you have java 1.5 and above it should compile just fine...

[ankit kumar]

See what java1.5 API says

format(Locale l, String format, Object... args)
Returns a formatted string using the specified locale, format string, and arguments.

String format(String format, Object... args)
Returns a formatted string using the specified format string and arguments.

[Jonathan Elkharrat]

so? the String is also an Object...
it's just like printf().
(and you should know that if you passed SCJP5)

[ankit kumar]

I think you have not have a look on the signature .

First agument should be Locale but in the book String is passed.

And the third agument should be array of the object not a single object or String ..

[Jonathan Elkharrat]

they use the oveloaded method that doesn't take a local.
and in varArgs place you can put zero, one, or any other number of Objects...