ref: 3642ff2c921852babc8be83d5614fbadd32a8818
dir: /Bookproj/Books.java/
package Bookproj; import java.util.HashMap; import java.util.TreeMap; public class Books { HashMap<BookAttr, String> Book = new HashMap<BookAttr, String>(); HashMap<String, HashMap> Booklist = new HashMap<String, HashMap>(); HashMap<String, TreeMap> Mkbl(HashMap<String, Book> bl) { HashMap<String, TreeMap> list = new HashMap<String, TreeMap>(); for (Book i : bl.values()) { list.put(i.getISBN(), i.toMap()); } return list; } }