Struts - Problem with nested iteration or double iteration

From:
Rudi <diaz_ruben2003@yahoo.com>
Newsgroups:
comp.lang.java.programmer
Date:
Tue, 30 Sep 2008 08:35:53 -0700 (PDT)
Message-ID:
<41bcb757-601a-4ce4-a351-630f110eda60@m73g2000hsh.googlegroups.com>
Hi Everyone,

  I'm trying to implement a nested iteration in a jsp and can't seem
to get this to work.

  Can anyone please help?

  Below is all the code. Thanks in advance.

Best regards,

Rudi

=========================================================
bookList.jsp

<%@ page language="java" pageEncoding="ISO-8859-1"%>
<%@ taglib uri="http://jakarta.apache.org/struts/tags-bean"
prefix="bean"%>
<%@ taglib uri="http://jakarta.apache.org/struts/tags-html"
prefix="html"%>
<%@ taglib uri="http://jakarta.apache.org/struts/tags-logic"
prefix="logic" %>
<%@ taglib uri="http://jakarta.apache.org/struts/tags-nested"
prefix="nested" %>

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<html>
    <head>
        <title>Show book list</title>
    </head>
    <body>
<table border="1">
    <tbody>

        <tr>
            <td>Author</td>
            <td>Book name</td>
            <td>Available</td>
            <td>&nbsp;</td>
            <td>&nbsp;</td>
        </tr>
        <%-- check if book exists and display message or iterate over books
--%>
        <logic:empty name="bookListForm" property="books">
            <tr>
                <td colspan="5">No books available</td>
            </tr>
        </logic:empty>
        <logic:notEmpty name="bookListForm" property="books">
            <logic:iterate name="bookListForm" property="books" id="book">
                <tr>
                    <%-- print out the book informations --%>
                    <td><bean:write name="book" property="author" /></td>
                    <td><bean:write name="book" property="title" /></td>
                    <td><html:checkbox disabled="true" name="book"
property="available" />
                    </td>

                    <%-- print out the edit and delete link for each book --%>
                    <td><html:link action="bookEdit.do?do=editBook" paramName="book"
                        paramProperty="id" paramId="id">Edit</html:link></td>
                    <td><html:link action="bookEdit.do?do=deleteBook"
paramName="book"
                        paramProperty="id" paramId="id">Delete</html:link></td>
                </tr>
            </logic:iterate>
        </logic:notEmpty>

        <%-- end iterate --%>

    </tbody>

</table>

<br>

One Iteration
<UL>
  <c:forEach var="book" items="${books}">
    <LI>Name = ${book.author}
  </c:forEach>
</UL>

<UL>
  <c:forEach var="book" items="${books}">
    <LI>Name = <c:out value="${book.author}" />
  </c:forEach>
</UL>

<!-- I tried this to get at least the top level name, but didn't work.
I'm not sure
     how to setup the inner forEach correctly. I tried but also get
errors.
     Error message is can't find bean -->

<UL>
  <c:forEach var="bookSection" items="$
{bookListForm.bookSectionList}">
    <LI>Name = <c:out value="${booksection.sectionName}" />
  </c:forEach>
</UL>

<!-- The code below doesn't work. Error message is unbalanced
nested:nest tag -->

<nested:nest property="bookSection" />
  <b><nested:write property="sectionName" /></b>
  <nested:iterate property="book" />
    <UL>
      <LI><nested:write property="title" /></LI>
    </UL>
  </nested:iterate>
</nested:nest>

</body>
</html>

=========================================================
Book.java

package com.mycompany.client;

public class Book implements java.io.Serializable {

    private static final long serialVersionUID = 1L;

    private long id;
    private String title;
    private String author;
    private String available;

    public Book() {}

    public Book(long id, String title, String author, String available) {
        this.id = id;
        this.title = title;
        this.author = author;
        this.available = available;
    }

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public String getAvailable() {
        return available;
    }

    public void setAvailable(String available) {
        this.available = available;
    }

}

=========================================================
BookSection.java

package com.mycompany.client;

import java.util.ArrayList;
import java.util.List;

public class BookSection implements java.io.Serializable {

    private static final long serialVersionUID = 1L;

    private List<Book> bookSec = new ArrayList<Book>();
    private Book latestBook;
    private String sectionName = null;

    public List<Book> getBookSec() {
        return bookSec;
    }

    public void setBookSec(List<Book> bookSec) {
        this.bookSec = bookSec;
    }

    public Book getLatestBook() {
        return latestBook;
    }

    public void setLatestBook(Book latestBook) {
        this.latestBook = latestBook;
    }

    public String getsSectionName() {
        return sectionName;
    }

    public void setSectionName(String sectionName) {
        this.sectionName = sectionName;
    }

}

=========================================================
BookListForm.java

package com.mycompany.client.struts.form;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

import javax.servlet.http.HttpServletRequest;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionMapping;
import com.mycompany.client.Book;
import com.mycompany.client.BookSection;

public class BookListForm extends ActionForm {

    private Collection books;
    private List<BookSection> bookSectionList;

    public Collection getBooks() {
        return books;
    }

    public void setBooks(Collection books) {
        this.books = books;
    }

    public void reset(ActionMapping mapping, HttpServletRequest request)
{
        books = new ArrayList();
    }

    public List<BookSection> getBookSectionList() {
        return bookSectionList;
    }

    public void setBookSectionList(List<BookSection> bookSectionList) {
        this.bookSectionList = bookSectionList;
    }

}

=========================================================
BookListAction.java

package com.mycompany.client.struts.action;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.swing.text.html.HTMLDocument.Iterator;

import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;

import org.apache.struts.action.DynaActionForm;

import com.mycompany.client.Book;
import com.mycompany.client.struts.form.BookListForm;
import com.mycompany.client.hibernate.*;

import org.hibernate.*;
import org.hibernate.criterion.Projections;

import com.mycompany.client.BookSection;

import java.util.*;

import java.util.ArrayList;
import java.util.List;

public class BookListAction extends Action {

    public ActionForward execute(ActionMapping mapping, ActionForm form,
            HttpServletRequest request, HttpServletResponse response) {

        BookListForm bookListForm = (BookListForm) form;

        SessionFactory factory = null;
        Session session = null;
        Collection <Book> books = new ArrayList<Book>();
        String author = null;
        String title = null;

          try {

         factory = HibernateSessionFactory.getSessionFactory();
         session = (Session) factory.openSession();

         List<Book>bks = session.createQuery("from Book ").list();

         System.out.println("Query Size = " + bks.size());

              if (bks.isEmpty()) {
             System.out.println("Could not get book using embedded
query");
              } else {
             for (int i = 0; i < bks.size(); i++) {
                 System.out.println("The title is " +
bks.get(i).getTitle());
             }
              }

              // Declare a BookSection List
              List<BookSection> booksList = new ArrayList<BookSection>();

              // Declare a BookSection
              BookSection bs1 = new BookSection();
              List<Book> sectionBook = new ArrayList<Book>();

              Book book1 = new Book();
              book1.setId(1);
              book1.setAuthor("Tom Clancy");
              book1.setTitle("The Hunt For Red October");
              book1.setAvailable("Y");
              sectionBook.add(book1);

              bs1.setSectionName("Mystery");

              Book book1Latest = new Book();
              book1Latest.setId(4);
              book1Latest.setAuthor("Agatha Christie");
              book1Latest.setTitle("And Then There Were None");
              book1Latest.setAvailable("Y");
              bs1.setLatestBook(book1Latest);

              // Declare another BookSection
              BookSection bs2 = new BookSection();
              List<Book> sectionBook2 = new ArrayList<Book>();

              Book book2 = new Book();
              book2.setId(1);
              book2.setAuthor("Naomi Wolf");
              book2.setTitle("Give Me Liberty");
              book2.setAvailable("Y");
              sectionBook2.add(book2);

              bs2.setSectionName("History");

              Book book2Latest = new Book();
              book2Latest.setId(4);
              book2Latest.setAuthor("Bob Woodward");
              book2Latest.setTitle("The War Within");
              book2Latest.setAvailable("Y");
              bs2.setLatestBook(book2Latest);

              booksList.add(bs1);
              booksList.add(bs2);

              // Reset and assign the list to the Form attribute
              // and the request
              bookListForm.reset(mapping, request);
              bookListForm.setBooks(bks);
              request.setAttribute("books", bks);

              request.setAttribute("booksect", booksList);

              bookListForm.setBookSectionList(booksList);

          } finally {
              session.close();
          }

          return mapping.findForward("showList");

    }
}

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