![[Figure05]](/onjava/2003/01/08/graphics/figure05.jpg)
Purpose
The purpose of Home.jsp is to produce a web page with a table displaying the contents of the addresses database, with links for adding new addresses to the database [RequestAdd.jsp]; deleting specific addresses from the database [RequestDelete.jsp]; and modifying specific addresses on the addresses database [RequestModify.jsp]. Figure 5 shows an example of AddressBook's home web page.
Outer Shell
This html code outputs the shell of the page with a link to RequestAdd.jsp at the bottom of the page:
<html>
<head>
<title>AddressBook: Home Page</title>
</head>
<body bgcolor="#ffffee">
<h1><center>AddressBook: Home Page</center></h1>
... code to display the table goes here ...
<br>
<hr>
<center>
<b><a href="RequestAdd.jsp">Add a New Address</a></b>
</center>
</body>
</html>
Display the Table
This html code displays the table and its headings:
<table align="center" cellpadding="2" cellspacing="2" border="1" width="80%" bgcolor="#dddddd">
<tr>
<th>Name</th>
<th>Address</th>
<th>Action</th>
<th>ID</th>
</tr>
... code to loop through all the table's rows goes here ...
</table>
Loop Through All the Table's Rows
This java code retrieves the AddressBook.AddressesDB instance stored in the the web application's "addressesDB" attribute by AddressBook.ContextListener:
AddressBook.AddressesDB addressesDB = (AddressBook.AddressesDB) application.getAttribute ("addressesDB");
Then the contents of the database are retrieved as a Collection:
Collection addresses = addressesDB.getAddresses ();
If the Collection is not null, and it contains some addresses [ie: its size is greater than 0], then the Collection is processed, retrieving each address in turn:
if (addresses != null)
{
if (addresses.size () > 0)
{
for (Iterator iterator = addresses.iterator(); iterator.hasNext(); )
{
AddressBook.Address address = (AddressBook.Address) iterator.next ();
... code to display an address in a table row goes here ...
}
}
}
Display an Address in a Table Row
This html code with interspersed java code displays an address as a row in a table. The java code simply retrieves individual fields from the address: address.getFullname () returns the fullname; address.getFulladdress () returns the fulladdress; and address.getId () returns the id. In the table's first column goes the full name; in the second column goes the full address; in the third column goes a link to RequestDelete.jsp, the word "or" and a link to RequestModify.jsp; and in the final column goes the id:
<tr>
<td>
<%= address.getFullname () %>
</td>
<td>
<%= address.getFulladdress () %>
</td>
<td align="center">
<b><a href="RequestDelete.jsp?id=<%= address.getId () %>">Delete</a></b>
or
<b><a href="RequestModify.jsp?id=<%= address.getId () %>">Modify</a></b>
</td>
<td align="center">
<%= address.getId () %>
</td>
</tr>
When the "Delete" link is selected the id parameter is passed to RequestDelete.jsp.
When the "Modify" link is selected the id parameter is passed to RequestModify.jsp.
<%@ page language="java" import="java.util.*" %>
<html>
<head>
<title>AddressBook: Home Page</title>
</head>
<body bgcolor="#ffffee">
<h1><center>AddressBook: Home Page</center></h1>
<table align="center" cellpadding="2" cellspacing="2" border="1" width="80%" bgcolor="#dddddd">
<tr>
<th>Name</th>
<th>Address</th>
<th>Action</th>
<th>ID</th>
</tr>
<%
AddressBook.AddressesDB addressesDB = (AddressBook.AddressesDB) application.getAttribute ("addressesDB");
Collection addresses = addressesDB.getAddresses ();
if (addresses != null)
{
if (addresses.size () > 0)
{
for (Iterator iterator = addresses.iterator(); iterator.hasNext(); )
{
AddressBook.Address address = (AddressBook.Address) iterator.next ();
%>
<tr>
<td>
<%= address.getFullname () %>
</td>
<td>
<%= address.getFulladdress () %>
</td>
<td align="center">
<b><a href="RequestDelete.jsp?id=<%= address.getId () %>">Delete</a></b>
or
<b><a href="RequestModify.jsp?id=<%= address.getId () %>">Modify</a></b>
</td>
<td align="center">
<%= address.getId () %>
</td>
</tr>
<%
}
}
}
%>
</table>
<br>
<hr>
<center>
<b><a href="RequestAdd.jsp">Add a New Address</a></b>
</center>
</body>
</html>
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