Question

I need to create a summary table at the end of a log with some values that
are obtained inside a class. The table needs to be printed in fixed-width
format. I have the code to do this already, but I need to limit Strings,
doubles and ints to a fixed-width size that is hard-coded in the code.

So, suppose I want to print a fixed-width table with

    int,string,double,string
    int,string,double,string
    int,string,double,string
    int,string,double,string

    and the fixed widths are: 4, 5, 6, 6.

If a value exceeds this width, the last characters need to be cut off. So
for example:

    124891, difference, 22.348, montreal

the strings that need to be printed ought to be:

    1248 diffe 22.348 montre

I am thinking I need to do something in the constructor that forces a
string not to exceed a certain number of characters. I will probably
cast the doubles and ints to a string, so I can enforce the maximum width
requirements.

I don’t know which method does this or if a string can be instantiated to
behave taht way. Using the formatter only helps with the
fixed-with formatting for printing the string, but it does not actually
chop characters that exceed the maximum length.

Answer 1

Use this to cut off the non needed characters:

String.substring(0, maxLength); 

Example:

String aString ="123456789";
String cutString = aString.substring(0, 4);
// Output is: "1234" 

To ensure you are not getting an IndexOutOfBoundsException when the input string is less than the expected length do the following instead:

int maxLength = (inputString.length() < MAX_CHAR)?inputString.length():MAX_CHAR;
inputString = inputString.substring(0, maxLength);

If you want your integers and doubles to have a certain length then I suggest you use NumberFormat to format your numbers instead of cutting off their string representation.