CODEWITHSUNDEEP
java
Matt
Matt

Reputation: 47

Having trouble using a boolean method in an if statement

I want to use the method isLong() from Book class and use it in displayLongBooks() which is in the BookCollection method. Class BookCollection has bookList variable. Variable bookList is of ArrayList type and contains the collection of all books. All objects in the ArrayList are of Book type.

 import java.util.ArrayList;
    public class BookCollection
    {
   ArrayList<Book> bookList = new ArrayList<Book>();

   public BookCollection(){
   bookList.add(new Book(1001-01-141514, "Letones", "CS", 611));
   bookList.add(new Book(1002-01-141424, "Lewis", "CS", 477));
   bookList.add(new Book(1003-01-141434, "Smith", "MATH", 698));
   bookList.add(new Book(1004-01-141444, "Smith", "CS", 617));
   bookList.add(new Book(1005-01-141454, "Brown", "CHEM", 326));
   bookList.add(new Book(1006-01-141464, "Smith", "BIO", 127));
   bookList.add(new Book(1007-01-141474, "Sanket", "CS", 998));
 }
 public String toString()
 {

 }
 public void displayLongBooks()
 {
     System.out.println();
     System.out.println("LONG BOOKS");
     if (isLong() == true)
     System.out.println(bookList);
 }
 public void displayBooksFromAuthor(String author)
 {

 }
 public void displayBooksFromArea(String area)
 {

 }
 public void displayAverageLength()
 {

 }
}




import java.util.*;
import java.io.*;
public class Book
{
    String author;
    String area;
    int isbn;
    int pages;

 public Book (int isbn, String author, String area, int pages)
   {
      this.isbn = isbn;
      this.author = author;
      this.area = area;
      this.pages = pages;     
   }
 public boolean isLong()
   {
     if(pages>600)
     return true;
     else
     return false;
   }
 public String toString()
 {
     return "ISBN: " + this.isbn + "Author: " + this.author
            + "Subject: " + this.area + "Pages: " + this.pages;
 } 
 /**PrintWriter outfile = new PrintWriter (new FileWriter("books.txt"));
 outfile.write("100101141514, Letones, CS, 611");
 outfile.write(100201141424, Lewis, CS, 477);
 outfile.write(100301141434, Smith, MATH, 698);
 outfile.write(100401141444, Smith, CS, 617);
 outfile.write(100501141454, Brown, CHEM, 326);
 outfile.write(100601141464, Smith, BIO, 127);
 outfile.write(100701141474, Sanket, CS, 998);
 outfile.close();**/
}

Upvotes: 1

Views: 129

Answers (1)

Elliott Frisch
Elliott Frisch

Reputation: 201409

Sounds like you need to iterate the bookList for Book(s) and call Book.isLong() for each one. Using a for-each loop that might look something like

public void displayLongBooks()
{
  System.out.println();
  System.out.println("LONG BOOKS");
  for (Book b : bookList) { // <-- for each Book b in bookList
    if (b.isLong()) { // no need for == true
      System.out.println(b); // <-- b, not bookList
    }
  }
}

Upvotes: 2

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