Eclipse-10.2 Creating the View

10.2 Creating the View

The first file that the user navigates to is the view file Ch10_01.jsp. In this file, we use various custom Struts tags to implement the display you see in Example 10-1. For example, the <html:form> tag creates a Struts-enabled form that can display controls, as you see in Example 10-1; we're setting the form's action attribute to the name we'll give the controller, Ch10_04.do, so when the user clicks the Submit button (with the caption "Place your order"), the data in the form will be forwarded to the controller.

Example 10-1. A sample JSP

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib uri="/WEB-INF/struts-bean.tld" prefix="bean" %>
<%@ taglib uri="/WEB-INF/struts-html.tld" prefix="html" %>
<%@ taglib uri="/WEB-INF/struts-logic.tld" prefix="logic" %>
<%@ taglib uri="/Ch10" prefix="Ch10" %>

<HTML>
    <HEAD>
        <TITLE>Here's the menu...</TITLE>
    </HEAD>
    
    <BODY>
        <H1>Here's the menu...</H1>
        <html:errors/>
        <Ch10:type/>
        <Ch10:items/>

        <html:form action="Ch10_04.do">
            <TABLE>
                <TR>
                    <TD ALIGN="LEFT" VALIGN="TOP">
                        <bean:message key="items"/>
                        <BR>
                        <logic:iterate id="items1" name="items">
                            <html:multibox property="items">
                                <%= items1 %>
                            </html:multibox>
                            <%= items1 %>
                            <BR>
                        </logic:iterate>
                    </TD>
                    <TD ALIGN="LEFT" VALIGN="TOP">
                        <bean:message key="type"/>
                        <BR>
                        <html:select property="type">
                            <html:options name="type"/>
                        </html:select>
                    </TD>
                </TR>
                <TR>
                    <TD ALIGN="LEFT">
                        <BR>
                        <bean:message key="email"/>
                        <html:text property="email"/>
                    </TD>
                <TR>
            </TABLE>
                  <BR>
            <html:submit value="Place your order"/>
        </html:form>
    </BODY>
</HTML>

Create this file by right-clicking the deployment folder in Eclipse and selecting New File, which automatically stores Ch10_01.jsp in the webapps/Ch10_01 folder.

As you see in Figure 10-1, the drop-down list we're presenting holds the items Pizza, Calzone, and Sandwich, and you can see the list of ingredients—Sausage, Cheese, Pepperoni, Meatballs, and Peppers—represented with a list of checkboxes. To make the items in these lists available to Struts HTML control in the view, we'll use two custom JSP tags, <Ch10:type> to return items like Pizza and Calzone, and <Ch10:items> to return items like Sausage, Cheese, and Pepperoni. As you can see in Example 10-1, we use the Struts <logic:iterate>, <html:multibox>, and <html:options> tags to create the needed HTML controls from those lists of items. You can see the implementation of these custom tags in Example 10-2 and Example 10-3. In Eclipse, create these files and store them in the src folder by right-clicking that folder and selecting New Class, placing the new classes, Ch10_02 and Ch10_03, in the org.eclipsebook.ch10 package.

Example 10-2. A custom tag class for order types

package org.eclipsebook.ch10;

import javax.servlet.jsp.tagext.TagSupport;

public class Ch10_02 extends TagSupport 
{
    public int doStartTag( ) 
      {
        
        String[] typeArray = {"", "Pizza", "Calzone", "Sandwich"};
        
        pageContext.setAttribute("type", typeArray);
        
        return SKIP_BODY;
    }
}

Example 10-3. A custom tag class for pizza toppings

package org.eclipsebook.ch10;

import javax.servlet.jsp.tagext.TagSupport;

public class Ch10_03 extends TagSupport 
{
   public int doStartTag( ) 
     {
       String[] itemsArray = {"Sausage", "Cheese", "Pepperoni", "Meatballs", "Peppers"};
        
       pageContext.setAttribute("items", itemsArray);
        
       return SKIP_BODY;
   }
}

To make these custom tags work, we need a tag library descriptor file, which you can see in Example 10-4. This file goes into deployment\WEB-INF.

Example 10-4. The TLD for the custom tags

<?xml version="1.0"?>
<!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.1//EN"
    "http://java.sun.com/j2ee/dtds/web-jsptaglibrary_1_1.dtd">

<taglib>
    <tlibversion>1.0</tlibversion>
    <jspversion>1.2</jspversion>
    <shortname>StrutsExample</shortname>
    <info>
        Supports the Struts Example
    </info>

    <tag>
        <name>type</name>
        <tagclass>org.eclipsebook.ch10.Ch10_02</tagclass>
        <bodycontent>empty</bodycontent>
   </tag>
  
    <tag>
        <name>items</name>
        <tagclass>org.eclipsebook.ch10.Ch10_03</tagclass>
        <bodycontent>JSP</bodycontent>
    </tag>
</taglib>

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