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Chapter 7 Examples
Download all Chapter 7 code
View code examples 7.25 to 7.35
7.25 7.26 7.27 7.28 7.29 7.30
7.31 7.32 7.33 7.34 7.35
Example 7.25 Composite View with Runtime Content Inclusion
<table border=1 valign="top" cellpadding="2%"
width="100%">
<tr>
<td><jsp:include page="news/worldnews.jsp"
flush="true"/> </td>
</tr>
<tr>
<td><jsp:include page="news/countrynews.jsp"
flush="true"/> </td>
</tr>
<tr>
<td><jsp:include page="news/customnews.jsp"
flush="true"/> </td>
</tr>
<tr>
<td><jsp:include page="news/astronomy.jsp"
flush="true"/> </td>
</tr>
</table>
Example 7.26 A Region and Sections
<region:render template='portal.jsp'>
<region:put section='banner' content = 'banner.jsp' />
<region:put section = 'controlpanel' content =
'ProfilePane.jsp' />
<region:put section='mainpanel' content =
'mainpanel.jsp' />
<region:put section='footer' content='footer.jsp' />
</region:render>
Example 7.27 Template Definition
<region:render section='banner'/>
<table width="100%">
<tr align="left" valign="middle">
<td width="20%">
<!-- menu region -->
<region:render section='controlpanel' />
</td>
<td width="70%" align="center">
<!-- contents -->
<region:render section='mainpanel' />
</td>
</tr>
</table>
Example 7.28 Section Subview – banner.jsp
<table width="100%" bgcolor="#C0C0C0">
<tr align="left" valign="middle">
<td width="100%">
<TABLE ALIGN="left" BORDER=1 WIDTH="100%">
<TR ALIGN="left" VALIGN="middle">
<TD>Logo</TD>
<TD><center>Sun Java Center</TD>
</TR>
</TABLE>
</td>
</tr>
</table>
Example 7.29 Controller Servlet with Command and Controller Strategy
public class Controller extends HttpServlet {
/** Processes requests for both HTTP
* <code>GET</code> and <code>POST</code> methods.
* @param request servlet request
* @param response servlet response
*/
protected void processRequest(HttpServletRequest
request, HttpServletResponse response)
throws ServletException, java.io.IOException {
String next;
try {
// Log pattern info
LogManager.recordStrategy(request,
"Service To Worker",
" ServletFront Strategy;" +
" JSPView Strategy; JavaBean helper Strategy");
LogManager.logMessage(request, getSignature(),
"Process incoming request. ");
// Use a helper object to gather parameter
// specific information.
RequestHelper helper = new
RequestHelper(request, response);
LogManager.logMessage(request, getSignature(),
"Getting command object helper");
// Get command object helper
Command command = helper.getCommand();
// delegate processing to the command object,
// passing request and response objects along
next = command.execute(helper);
/** If the above command returns a value, we
* will dispatch from the controller. In this
* example, though, the command will use a
* separate dispatcher component to choose a
* view and dispatch to that view. The command
* object delegates to this dispatcher
* component in its execute method, above, and
* control should not return to this point **/
}
catch (Exception e) {
LogManager.logMessage(
"EmployeeController(CommandStrategy)",
e.getMessage() );
/** ApplicationResources provides a simple API
* for retrieving constants and other
* preconfigured values**/
next = ApplicationResources.getInstance().
getErrorPage(e);
}
dispatch(request, response, next);
}
/** Handles the HTTP <code>GET</code> method.
* @param request servlet request
* @param response servlet response
*/
protected void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, java.io.IOException {
processRequest(request, response);
}
/** Handles the HTTP <code>POST</code> method.
* @param request servlet request
* @param response servlet response
*/
protected void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, java.io.IOException {
processRequest(request, response);
}
/** Returns a short description of the servlet. */
public String getServletInfo() {
return getSignature();
}
/** dispatcher method */
protected void dispatch(HttpServletRequest request,
HttpServletResponse response,
String page) throws
javax.servlet.ServletException,
java.io.IOException {
RequestDispatcher dispatcher =
getServletContext().getRequestDispatcher(page);
dispatcher.forward(request, response);
}
public void init(ServletConfig config) throws
ServletException {
super.init(config);
}
public void destroy() { }
private String getSignature() {
return "ServiceToWorker-Controller";
}
}
Example 7.30 Command Interface
public interface Command {
public String execute(RequestHelper helper) throws
javax.servlet.ServletException, java.io.IOException;
}
Example 7.31 ViewAccountDetailsCommand
public class ViewAccountDetailsCommand implements
Command {
public ViewAccountDetailsCommand() { }
// view account details operation
public String execute(RequestHelper helper)
throws javax.servlet.ServletException,
java.io.IOException {
/** This will tell the user that a system error
* has occured and will typically not be seen. It
* should be stored in a resource file **/
String systemerror =
"/jspdefaultprocessingerror.jsp";
LogManager.logMessage(helper.getRequest(),
"ViewAccountDetailsCommand",
"Get Account Details from an adapter object");
/** Use an adapter to retrieve data from business
* service, and store it in a request attribute.
* Note: Object creation could be avoided via
* factory, but for example purposes object
* instantiation is shown **/
AccountingAdapter adapter = new
AccountingAdapter();
adapter.setAccountInfo(helper);
LogManager.logMessage(helper.getRequest(),
"ViewAccountDetailsCommand", "processing complete");
/** Note: Object creation could be avoided via
* factory, but for example purposes object
* instantiation is shown**/
Dispatcher dispatcher = new Dispatcher();
dispatcher.dispatch(helper);
/** This return string will not be sent in a
* normal execution of this scenario, because
* control is forwarded to another resource
* before reaching this point. Some commands do
* return a String, though, so the return value
* is included for correctness. **/
return systemerror;
}
}
Example 7.32 AccountingAdapter
public class AccountingAdapter {
public void setAccountInfo(
RequestHelper requestHelper) {
LogManager.logMessage(
requestHelper.getRequest(),
"Retrieving data from business tier");
// retrieve data from business tier via
// delegate. Omit try/catch block for brevity.
AccountDelegate delegate =
new AccountDelegate();
AccountVO account =
delegate.getAccount(
requestHelper.getCustomerId(),
requestHelper.getAccountKey());
LogManager.logMessage(
requestHelper.getRequest(),
"Store account value object in request attribute");
// transport data using request object
requestHelper.getRequest().setAttribute(
"account", account);
}
}
Example 7.33 View – accountdetails.jsp
<html>
<head><title>AccountDetails</title></head>
<body>
<jsp:useBean id="account" scope="request"
class="corepatterns.util.AccountVO" />
<h2><center> Account Detail for <jsp:getProperty
name="account" property="owner" />
</h2> <br><br>
<table border=3>
<tr>
<td>
Account Number :
</td>
<td>
<jsp:getProperty name "account" property="number" />
</td>
</tr>
<tr>
<td>
Account Type:
</td>
<td>
<jsp:getProperty name="account" property="type" />
</td>
</tr>
<tr>
<td>
Account Balance:
</td>
<td>
<jsp:getProperty name="account" property="balance" />
</td>
</tr>
<tr>
<td>
OverDraft Limit:
</td>
<td>
<jsp:getProperty name="account"
property="overdraftLimit" />
</td>
</tr>
</table>
<br>
<br>
</center>
<%@ include file="/jsp/trace.jsp" %>
</body>
</html>
Example 7.34 Dispatcher View Controller Servlet
public class Controller extends HttpServlet {
/** Processes requests for both HTTP
* <code>GET</code> and <code>POST</code> methods.
* @param request servlet request
* @param response servlet response
*/
protected void processRequest(HttpServletRequest
request, HttpServletResponse response)
throws ServletException, java.io.IOException {
String nextview;
try {
LogManager.recordStrategy(request,
"Dispatcher View",
" Servlet Front Strategy; " +
"JSP View Strategy; Custom tag helper Strategy");
LogManager.logMessage(request, getSignature(),
"Process incoming request. ");
// Use a helper object to gather parameter
// specific information.
RequestHelper helper = new
RequestHelper(request, response);
LogManager.logMessage(request,
getSignature(), " Authenticate user");
Authenticator auth = new BasicAuthenticator();
auth.authenticate(helper);
//This is an oversimplification for the sake of
// simplicity. Typically, there will be a
// mapping from logical name to resource name at
// this point
LogManager.logMessage(request, getSignature(),
"Getting nextview");
nextview = request.getParameter("nextview");
LogManager.logMessage(request, getSignature(),
"Dispatching to view: " + nextview);
}
catch (Exception e) {
LogManager.logMessage(
"Handle exception appropriately",
e.getMessage() );
/** ApplicationResources provides a simple API
* for retrieving constants and other
* preconfigured values**/
nextview = ApplicationResources.getInstance().
getErrorPage(e);
}
dispatch(request, response, nextview);
}
/** Handles the HTTP <code>GET</code> method.
* @param request servlet request
* @param response servlet response
*/
protected void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, java.io.IOException {
processRequest(request, response);
}
/** Handles the HTTP <code>POST</code> method.
* @param request servlet request
* @param response servlet response
*/
protected void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, java.io.IOException {
processRequest(request, response);
}
/** Returns a short description of the servlet. */
public String getServletInfo(){
return getSignature();
}
public void init(ServletConfig config) throws
ServletException {
super.init(config);
}
public void destroy() { }
/**
* dispatcher method
*/
protected void dispatch(HttpServletRequest request,
HttpServletResponse response, String page)
throws javax.servlet.ServletException,
java.io.IOException {
RequestDispatcher dispatcher =
getServletContext().
getRequestDispatcher(page);
dispatcher.forward(request, response);
}
private String getSignature() {
return "DispatcherView-Controller";
}
}
Example 7.35 View – accountdetails.jsp
<%@ taglib uri="/web-INF/corepatternstaglibrary.tld"
prefix="corepatterns" %>
<html>
<head><title>AccountDetails</title></head>
<body>
<corepatterns:AccountQuery
queryParams="custid,acctkey" scope="request" />
<h2><center> Account Detail for <corepatterns:Account
attribute="owner" /></h2> <br><br>
<tr>
<td>Account Number :</td>
<td><corepatterns:Account attribute="number" /></td>
</tr>
<tr>
<td>Account Type:</td>
<td><corepatterns:Account attribute="type" /></td>
</tr>
<tr>
<td>Account Balance:</td>
<td><corepatterns:Account attribute="balance" /></td>
</tr>
<tr>
<td>OverDraft Limit:</td>
<td><corepatterns:Account attribute="overdraftLimit" /></td>
</tr>
<table border=3>
</table>
</corepatterns:AccountQuery>
<br>
<br>
</center>
<%@ include file="/jsp/trace.jsp" %>
</body>
</html>
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