gistfile1.txt

package Singleton;

public class Printer {
    // Private - It should be accessed by only getInstance Methods()
    private static Printer instance;

    private Printer() {
        // Private Constructor to make sure that no more than one instance is created at a given time.
    }

    // Double check Locking
    public static Printer getInstance() {
        if (instance == null) {
            // This block creates instance so that min threads wait and only for first time.
            synchronized (Printer.class) {
                if (instance == null) {
                    instance = new Printer();
                }
            }
        }
        return instance;
    }

    void print(Object obj) {
        if (obj instanceof MSWord) {

            MSWord wordInstance = (MSWord) obj;
            System.out.println("I am Printing " + wordInstance.page);
        } else {
            AcrobatReader pdfInstance = (AcrobatReader) obj;
            System.out.println("I am Printing " + pdfInstance.page);
        }

    }
}