xmlborrowersformatter.java

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import java.util.*;

/**
 * This class implements a method that obtains an XML
 * representation of a {@link BorrowerDatabase} object.
 *
 * @author author name
 * @version  1.0.0
 * @see BorrowersFormatter
 * @see BorrowerDatabase
 * @see Borrower
 * @see BorrowedItems
 * @see CatalogItem
 */
public class XMLBorrowersFormatter
    implements BorrowersFormatter  {

    /* Line separator*/
    private final static String NEW_LINE =
        System.getProperty("line.separator");

    /* single instance of this class */
    static private XMLBorrowersFormatter singletonInstance = null;

    /**
     * Obtains the single instance of class
     * <code>XMLBorrowersFormatter</code>
     *
     * @return the single instance  of class
     *         <code>XMLBorrowersFormatter</code>
     */
    static public XMLBorrowersFormatter getSingletonInstance() {

        if (singletonInstance == null) {
            singletonInstance = new XMLBorrowersFormatter();
        }

        return singletonInstance;
    }

    /*
     * The constructor is declared private so other classes cannot
     * create an instance of this class.
     */
    private XMLBorrowersFormatter() {
    }

    /**
     * Obtains an XML representation of the specified borrower
     * database.
     *
     * @param borrowerDB  the borrower database.
     * @return  a XML representation of the specified
     *          {@link BorrowerDatabase} object.
     */
    public String formatBorrowers (BorrowerDatabase borrowerDB) {

        String out = "<BorrowerDatabase>" + NEW_LINE ;

        for (Iterator i = borrowerDB.getBorrowersIterator();
                i.hasNext();) {

            Borrower borrower = (Borrower) i.next();

            out += "  <Borrower id=\""
                   + borrower.getId()
                   + "\" name=\""
                   + borrower.getName()
                   + "\">"
                   + NEW_LINE;

            BorrowedItems items = borrower.getBorrowedItems();

            if (items.getNumberOfItems() > 0) {
                out += "    <BorrowedItems>" + NEW_LINE;

                for (Iterator j = items.getItemsIterator();
                        j.hasNext();) {

                    CatalogItem item = (CatalogItem) j.next();

                    out += "      <CatalogItem id=\""
                           + item.getCode()
                           + "\">"
                           + item.getTitle()
                           + "</CatalogItem>" + NEW_LINE;
                }
                out += "    </BorrowedItems>" + NEW_LINE;
            }
            out += "  </Borrower>" + NEW_LINE;
        }
        out += "</BorrowerDatabase>";

        return out;
    }
}