Can I use the builder pattern on a Java Enum

Question

I\'m re-writing some code, and I\'ve decided the way to recreate the class, as there are a fixed number of sheets, I\'m creating them as enums. This is a decision based on the r

Answer 1

You can use instance blocks (often incorrectly called "double brace initializers") to customise construction with arbitrary code:

public enum workBookSheet {

    mySheet1("Name1", "mainSheet1.xls", true, 1) {{
        addSubSheet("pathToSubSheet1.xls");
    }},
    mySheet2("Name2", "mainSheet2.xls", true, 2) {{
        // you can use the fluent interface:
        addHeaderSheet("pathToHeaders.xls").addSubSheet("pathtoSubSheet2.xls");
        // but I would prefer coding separate statements:
        addHeaderSheet("pathToHeaders.xls");
        addSubSheet("pathtoSubSheet2.xls");
    }};

    // rest of your class the same...
}

Employing this syntax allows you to work around the limitations imposed by an enum but still have the brevity, convenience and flexibility of a builder/fluent pattern.