package ora.jwsnut.chapter6.serializerbookservice;

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 SBookServiceServantData {
    
    /**
     * 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;

     /**
      * Categorized data in the form of a HashMap.
      */
    private static HashMap categorizedBookMap;
    
    /**
     * 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
            ArrayList list = new ArrayList();
            try {
                InputStream is = 
                    SBookServiceServantData.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() == 4) {
                        list.add(new BookInfo(st.nextToken(), st.nextToken(),
                                st.nextToken(), Double.parseDouble(st.nextToken())));
                    } else if (st.countTokens() == 5) {
                        list.add(new ElectronicBookInfo(st.nextToken(), st.nextToken(),
                        st.nextToken(), Double.parseDouble(st.nextToken()),
                        st.nextToken()));
                    }
                }
            } catch (Exception ex) {
                // Just return an empty or partial list                
                ex.printStackTrace();
            }
            
            // Convert the list to an array
            bookInfo = new BookInfo[list.size()];
            list.toArray(bookInfo);
        }
        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;
    }
}