package ora.jwsnut.chapter6.docbookservice;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.StringTokenizer;

/**
 * A class that loads the data for the book service 
 * and provides access to it in the form of an array
 * of BookInfo objects.
 */
class DocBookServiceServantData {
    
    /**
     * The loaded data, created when it is first requested
     */
    private static BookInfo[] bookInfo;
    
    /**
     * The data in the form of a HashMap, created when it is
     * first requested.
     */
    private static HashMap bookMap;
    
    /**
     * Gets the book info, creating it if necessary.
     * @return an array of BookInfo objects with one entry
     * for each book.
     */
    static BookInfo[] getBookInfo() {
        if (bookInfo == null) {
            // First request - create the data
            loadData();
        }
        return bookInfo;
    }   
    
    /** 
     * Returns all of the books known to the book
     * service in the form of a <code>HashMap</code> where the
     * key to each entry is the book title in upper case
     * and the value is a <code>BookInfo</code> object.
     */
    static HashMap getBookInfoHashMap() {
        if (bookMap == null) {
            BookInfo[] info = getBookInfo();
            bookMap = new HashMap();
            for (int i = 0; i < info.length; i++) {
                BookInfo book = info[i];
                bookMap.put(book.getTitle().toUpperCase(), book);
            }
        }
        return bookMap;
    }
    
    /**
     * Loads the book and stock info 
     */
    private static void loadData() {
        ArrayList list = new ArrayList();
        try {
            InputStream is = 
                DocBookServiceServantData.class.getResourceAsStream("booklist.txt");
            BufferedReader reader = new BufferedReader(new InputStreamReader(is));
            String line;
            while ((line = reader.readLine()) != null) {
                StringTokenizer st = new StringTokenizer(line, "!");
                if (st.countTokens() == 5) {
                    list.add(new BookInfo(st.nextToken(), st.nextToken(),
                            st.nextToken(), Double.parseDouble(st.nextToken()),
                            Integer.parseInt(st.nextToken())));
                }
            }
        } catch (Exception ex) {
            // Just return an empty or partial list                
            ex.printStackTrace();
        }

        // Convert the lists to arrays
        bookInfo = new BookInfo[list.size()];
        list.toArray(bookInfo);
    }
}