Dynamically formatting a string

Question

Before I wander off and roll my own I was wondering if anyone knows of a way to do the following sort of thing...

Currently I am using MessageFormat to create some strings. I now have the requirement that some of those strings will have a variable number of arguments.

For example (current code):

MessageFormat.format("{0} OR {1}", array[0], array[1]);

Now I need something like:

// s will have "1 OR 2 OR 3"
String s = format(new int[] { 1, 2, 3 });

and:

// s will have "1 OR 2 OR 3 OR 4"
String s = format(new int[] { 1, 2, 3, 4 });

There are a couple ways I can think of creating the format string, such as having 1 String per number of arguments (there is a finite number of them so this is practical, but seems bad), or build the string dynamically (there are a lot of them so this could be slow).

Any other suggestions?

Thomas Jung · Accepted Answer · 2010-03-23 08:10:26Z

6

Unless, I'm missing something this is plain old join. Until Java 7 gets String.join (no joke) there are some implementations around like Apache commons lang StringUtils.join.

StringUtils.join(new Integer[] { 1, 2, 3, 4 }, "OR");

The only problem is that is does not work on primtive int[] arrays directly.

answered Mar 23, 2010 at 8:10

Thomas Jung

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2 Comments

Bozho Over a year ago

(+1) but the same lib has ArrayUtils.toObject(..) to convert the primitive array to the wrapper ;)

TofuBeer Over a year ago

the array is actually String so no issue at all. I'll go give it a try and see how it does - thanks.

dfa · Accepted Answer · 2010-03-23 09:33:03Z

1

using Dollar should be simple:

String s1 = $(1, 3).join(" OR ");
String s2 = $(1, 4).join(" OR ");

where $(1, n) is a range object wrapper (there are wrappers for Collections, arrays, CharSequences, etc).

edited Mar 23, 2010 at 9:33

answered Mar 23, 2010 at 9:21

dfa

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1 Comment

TofuBeer Over a year ago

interesting, don't want to add a new dependency to the project, but I'll take a deeper look at it.

Koray Tugay · Accepted Answer · 2021-07-11 03:36:37Z

1

You can use the String#join method from Java 8 and onwards, which will allow you to join strings with the given delimiter.

String.join(" OR ", "a", "b", "c")

edited Jul 11, 2021 at 3:36

Koray Tugay

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answered Jul 11, 2021 at 3:23

Satya

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Comments

Will · Accepted Answer · 2010-03-23 06:59:14Z

0

I think the simplest solution is writing a quick function that runs through the arguments in a for loop, appending “ OR ” + arg[i] to a StringBuilder, (with a special case for the first argument), then returning the StringBuilder's toString() value. How's this?

String format(String... args) {
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < args.length; i++) {
        if (i > 0) {
            sb.append(" OR ");
        }
        sb.append(args[i]);
    }
    return sb.toString();
}

answered Mar 23, 2010 at 6:59

Will

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