CODEWITHSUNDEEP
javaarrayslistwhitespaceapache-stringutils
Tee Jay
Tee Jay

Reputation: 113

Separate list items by whitespace and higher level metrics by tabs

I have the following functions:

 public String tabSerializer(String log, String time) {
        StringJoiner joiner = new StringJoiner("\t");
        addValue(company, joiner);
        addValue(users, joiner);
        ...
        return joiner.toString();
     }


  private static void addValue(Object value, StringJoiner joiner){
        if(value instanceof List){
            addValuesFromList((List<?>)value, joiner);
        }
        else{
            joiner.add(String.valueOf(value));
        }
    }
  private static void addValuesFromList(List<?> arr, StringJoiner joiner) {
        for(int i=0; i<arr.size(); i++){
            Object value = arr.get(i);
            addValue(value, joiner);
        }
    }

company is a List of strings. Example: [Apple, mango]. I am trying to separate all the values passed in tabSerializer() function by a tab. However, using my current code, I am getting tabs even between list values (eg, apple mango) instead of whitespace.

I want to separate list values by whitespaces while still separate all higher level dimesnions by tabs.

I tried adding: value= value + " " in the "addValuesFromList()" function but don't know how to further use that to integrate with the joiner.

Any help would be appreciated.

Upvotes: 0

Views: 61

Answers (2)

Vadim
Vadim

Reputation: 4120

Or if you still want to use StringJoiner use second joiner in addValuesFromList.

private static void addValuesFromList(List<?> arr, StringJoiner joiner) {
    StringJoiner spaceJoiner = new StringJoiner(" ");

    for (int i = 0; i < arr.size(); i++) {
        Object value = arr.get(i);
        spaceJoiner.add(String.valueOf(value));
    }
    String spacedValue = spaceJoiner.toString(); 
    addValue(spacedValue, joiner);

}

will it do what you need?

Upvotes: 2

Andreas
Andreas

Reputation: 159096

StringJoiner is a nice helper class to:

... construct a sequence of characters separated by a delimiter ...

Since you need multiple delimiters, StringJoiner is not the best tool for the job.

Instead, just do it yourself using StringBuilder:

public String tabSerializer(Object... values) {
    StringBuilder buf = new StringBuilder();
    boolean first = true;
    for (Object value : values) {
        if (first)
            first = false;
        else
            buf.append('\t');
        appendValue(buf, value);
    }
    return buf.toString();
}

private static void appendValue(StringBuilder buf, Object value) {
    if (value instanceof List) {
        appendListValues(buf, (List<?>) value);
    } else {
        buf.append(value);
    }
}

private static void appendListValues(StringBuilder buf, List<?> list) {
    boolean first = true;
    for (Object value : list) {
        if (first)
            first = false;
        else
            buf.append(' ');
        buf.append(value);
    }
}

Test

System.out.println(tabSerializer("Foo", Arrays.asList("A", "B"), "Bar"));

Output (tab visualized using → arrow)

Foo→A B→Bar

Upvotes: 0

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