Working around superfirst

Question

Here, AsciiChecker enables the matrix specification in the text form.

abstract class AsciiChecker extends AlgoritmicChecker {

    String[] ascii;

    AsciiChecker(String title, final String ... ascii) {
        super(title, ascii[0].length(), ascii.length); // calls isCovered
    };

    boolean isCovered(int test, int statement) {
        return ascii[statement].charAt(test) == '1';
    }           
}

It needs the matrix argument to be available in the isCovered call. Tell me how do I shoot my leg if I initialize the field before using it,

    AsciiChecker(String title, final String ... ascii) {
        this.ascii = ascii;
        super(title, ascii[0].length(), ascii.length); // calls isCovered
    };

Answer 1

If your superclass is using data your array, pull up String[] ascii; to the superclass, initialize this field there and in isCovered access it via getter or modify signature of isCovered and pass proper array as an argument.

Answer 2

You need to get rid of that call of an overrideable method in the superclass. From Effective Java, item 18:

Move the body of each overridable method to a private "helper method" and have each overridable method invoke its private helper method. Then replace each self-use of an overridable method with a direct invocation of the overridable method's private helper method.