How to abbreviate string at the middle without cutting words

Question

I am using StringUtils.abbreviateMiddle(string, middle, targetLength); to abbreviate string in the middle but using this method cuts off the word. Is there a way such that it will only cut off string at the space nearest to the middle position of the string?

public static String shortenStringMiddle(String string, String middle, int targetLength) {
    targetLength = Math.abs(targetLength);

    if (string != null && string.length() > targetLength) {

        return StringUtils.abbreviateMiddle(string, middle, targetLength);
    }
    else {
        return string;
    }
}

Input if applied to this text:

Disease Control in Fish and Shrimp Aquaculture in Southeast Asia - Diagnosis and Husbandry Techniques: Proceedings of the SEAFDEC-OIE Seminar-Workshop on Disease Control in Fish and Shrimp Aquaculture in Southeast Asia - Diagnosis and Husbandry Techniques, 4-6 December 2001, Iloilo City, Philippines

System.out.println(StringUtils.abbreviateMiddle("Disease Control in Fish and Shrimp Aquaculture in Southeast Asia - Diagnosis and Husbandry Techniques: Proceedings of the SEAFDEC-OIE Seminar-Workshop on Disease Control in Fish and Shrimp Aquaculture in Southeast Asia - Diagnosis and Husbandry Techniques, 4-6 December 2001, Iloilo City, Philippines", " … ", 220));

Output:

Disease Control in Fish and Shrimp Aquaculture in Southeast Asia - Diagnosis and Husbandry Techniques: Procee … aculture in Southeast Asia - Diagnosis and Husbandry Techniques, 4-6 December 2001, Iloilo City, Philippines

The word Proceedings was cut off to Procee and Aquaculture to aculture

My ideal output would be:

Disease Control in Fish and Shrimp Aquaculture in Southeast Asia - Diagnosis and Husbandry Techniques: Proceedings … Aquaculture in Southeast Asia - Diagnosis and Husbandry Techniques, 4-6 December 2001, Iloilo City, Philippines

I've searched here in SO and similar questions only relates to abbreviate string adding an ellipsis at the end.

Answer 1

Here's a rough shot at it. Obviously you could implement cleaner fallback methods for cases where the string doesn't contain sufficient spaces etc., but as a base to start from, it should do just fine.

public static String abbreviateMiddle(String input, String middle, int targetLength) {
    if (input == null || input.length() <= targetLength) {
        return input;
    }

    int inputLength = input.length();
    int halfTargetLength = (targetLength - middle.length()) / 2;

    int startLastSpace = input.substring(0, halfTargetLength).lastIndexOf(" ");
    int endFirstSpace = input.indexOf(" ", inputLength - halfTargetLength);

    if (startLastSpace != -1 || endFirstSpace != -1) {
        return input.substring(0, startLastSpace)
                + middle
                + input.substring(endFirstSpace + 1, inputLength);
    }

    return input;
}

With your example text, the following call

System.out.println(abbreviateMiddle(exampleText, " ... ", 240));

will return

Disease Control in Fish and Shrimp Aquaculture in Southeast Asia - Diagnosis and Husbandry Techniques: Proceedings ... Aquaculture in Southeast Asia - Diagnosis and Husbandry Techniques, 4-6 December 2001, Iloilo City, Philippines

Setting the targetLength to 220 will return

Disease Control in Fish and Shrimp Aquaculture in Southeast Asia - Diagnosis and Husbandry Techniques: ... in Southeast Asia - Diagnosis and Husbandry Techniques, 4-6 December 2001, Iloilo City, Philippines

Answer 2

Try this:

public String abbreviateMiddle(String string, String middle, int targetLength) {
    String[] ssplit = string.split(" ");
    String first = "";
    String second = "";
    for (int i = 0; i < ssplit.length; i++) {
        if (first.length() < targetLength / 2) {
            first += ssplit[i] + " ";
        } else {
            break;
        }
    }
    for (int i = ssplit.length - 1; i >= 0; i--) {
        if (second.length() < targetLength / 2) {
            second = ssplit[i] + " " + second;
        } else {
            break;
        }
    }

    return first + middle + second;
}

If you want the result string to be maximum length but strictly less than targetLength (rather than the above code which returns the minimum string that has a length GREATER than targetLength), use

if (first.length() + ssplit[i].length() < targetLength /2)

and

if (second.length() + ssplit[i].length() < targetLength / 2)

instead.