2. CGS – 4854 Summer 2012 Web Site Construction and Management Instructor: Francisco R. Ortega Chapter 3 Part 1

3. Today’s Lecture Chapter 4 Quiz 4 will be short and given at the start of class (June 14) – Covers chapter 3 and Chapter 4.

4. Mid-Term Mid-Term June 21 st. – Chapters 1,2,3 and 4. Possible review for mid-term – June 14 (after quiz 4) or June 19 Extra Credit for Mid-Term – Extra credit question may be Java related or Regular Expressions (if covered before the exam) You are allowed to bring one letter size paper to the exam

5. Enhancing the Controller We will be adding some cool features to our controller from Chapter 3 – Logging – …

6. Logging Excellent resource to keep debugging information We will be using log4j – http://logging.apache.org/log4j/1.2/ http://logging.apache.org/log4j/1.2/

7. Log4j Up to 5 levels – It will only write the same level or lower levels Fatal errors always are written to the log – FATAL, ERROR, WARN, INFO, DEBUG

8. Log4j FILE LEVELERROR MESSAGES Level.FATALFatal Level.ERRORFatal, error Level.WARNFatal, error, warn Level.INFOFatal, error, warn, info Level.DEBUGFatal, error, warn, info, debug

9. Log4J METHODWRITTEN TO ? fatal()Fatal, error, warn, info, debug error()Error, warn, info, debug warn()Warn, info, debug info()Info, debug debug()debug METHODACEEPTED METHODS FATALfatal() ERRORfatal(), error() WARNfatal(), error(), warn() INFOfatal(), error(), warn(), info() DEBUGfatal(), error(), warn(), info(), debug()

10. Examples warn(“optional playerName variable is empty”); – Warn, info, debug

11. Initialization Servlet It is great to have servlets that set up initial values/classes that you will need – They will be called once – It cannot be called by a user via the browser

12. Initialization Servlet + Log4j InitLog4j shared.InitLog4j logPath /WEB-INF/logs/error.log 1

13. Question Why don’t we need mapping for the initialization server?

14. Initialization Servlet (pg. 109) public class InitLog4j extends HttpServlet { public void init() { … } private FileAppender getAppender(String filename) { … } private void initLogger(String name, FileAppender appender, Level level) { … } }

15. Helper Methods: getAppender Private FileAppender getAppender(String fileName) { RollingFileAppender appender = null; try{ Appender = new RollingFileAppender(…..) appender.setMaxBackupIndex(5); Appender.setMaxFileSize(“1MB”); } Catch (IOException ex) { } return appender; }

16. Helper Methods: initLogger private void initLogger(String name, FileAppender Name, Level level) { Logger logger; If (name == null) { logger = Logger.getRootLogger(); } else { logger = Logger.getLogger(name); } logger.setLevel(level); logger.addAppender(appender) Logger.info(“Starting “ + logger.getName(); }

17. Init() public void init() { String initPath = getInitParameter(“logPath”); String logPath = “/WEB-INF/logs/errors.log” If (initPath != null) logPath = initPath; FileAppender appender = getAppender(logPath) If (appender == null) return; initLogger(null, appender, Level.ERROR); initLogger(“org.apache.commons.beanutils”, appender, Level.DEBUG); }

18. Adding more initialization parameters … logPath /WEB-INF/logs/error.log logName error.log logLevel Level.Debug …

19. Note: shared Package (book) The helper based classed has been renamed to HelperBaseCh4 (and ch5, ch6) in the shared package. HelperBaseClass has 4 parameters now – servlet,request,response,logger Checked moodle or the book site for the shared package

20. Initializing the logger We will initialize in the the base class!

21. public HelperBaseCh4( HttpServlet servlet, HttpServletRequest request, HttpServletResponse response) { this.servlet = servlet; this.request = request; this.response = response; initLogger(); } protected void initLogger() { String logName = "bytesizebook.webdev"; String initName = servlet.getInitParameter("logName"); if (initName != null) logName = initName; Level logLevel = Level.DEBUG; String strLevel = servlet.getInitParameter("logLevel"); if (strLevel != null) { logLevel = Level.toLevel(strLevel); } logger = Logger.getLogger(logName); logger.setLevel(logLevel); } … }

22. Hidden Fields -- ${helper} 1.Controller Helper a)Has bean with data entered by user b)Write itself to the session ( this ) 2.Hidden fields a)Stores data b)Send it back to application Trigger by button 3.Session State 1.Data is stored for duration of the session. 2.Controller Helper can retrieve it from the session

23. Hidden Fields – Big Picture

24. Eliminating Hidden Fields You may want a site to let you restart You may want to save a helper from a different application

25. Note: Using enumeration If (state == SessionData.READ) { ….. } public enum StreetLight { RED, YELLOW, GREEN}; http://docs.oracle.com/javase/tutorial/java/javaOO/enum.html

26. Helper Methods addHelperToSession – setAttribute to add helper – Retrieve old helper from session copyFromSession – Copy specific values from old session In our particular example, it copies the entire bean

27. public void addHelperToSession(String name, SessionData state) { if (SessionData.READ == state) { Object sessionObj = request.getSession().getAttribute(name); if (sessionObj != null) { copyFromSession(sessionObj); } request.getSession().setAttribute(name, this); }

28. public void copyFromSession(Object sessionHelper) { if (sessionHelper.getClass() == this.getClass()) { ControllerHelper oldHelper = (ControllerHelper)sessionHelper; data = oldHelper.data; }

29. Packages needed for BaseHelperCh4 import java.io.IOException; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.log4j.Level; import org.apache.log4j.Logger;

30. public abstract class HelperBaseCh4 { … protected abstract void copyFromSession(Object helper); public void addHelperToSession(String name, SessionData state) { … } public void addHelperToSession(String name, boolean checkSession) { … }

31. Java Question Why use abstract classes? Why is it that we can call an abstract method from the base class ? What would happened if we didn’t have an abstract method for our example? Can the implementation of the copyFromSession Method be moved to the base class? Explain.

32. NOTE: CopyToSession By making the copyToSession an abstract method in the HelperBase, then the addHelperToSession method can be defined in the base class.

33. AddHelperToSession Parameter name should be unique – In our book, we keep it the same – If you were using multiple controllers Make sure to have a different name for each helper Parameter state – Use READ when:  Need to read old helper. —Use IGNORE when:  Start of a new request

34. HelperBase HttpServletRequest request HttpServletResponse response Logger logger Abstract copyFromSession() addHelperToSession() ControllerHelper RequestData data doGet() getData() copyFromSession()

35. copyFromSession if (sessionHelper.getClass() == this.getClass() ){ ControllerHelper helper = (ControllerHelper)sessionHelper; data = helper.data; } It’s important to know that the helper is the same type of controller for the application

36. ControllerHelper.doGet() public void doGet() throws ServletException, IOException { addHelperToSession(“helper”,SessionData.READ); … }

37. Location JSP If not relative – Must specify path

38. Location of JSP – OLD WAY if (request.getParameter("processButton") != null) { address = "/ch3/dataBean/Process.jsp"; } else if (request.getParameter("confirmButton") != null) { address = "/ch3/dataBean/Confirm.jsp"; } else { address = "/ch3/dataBean/Edit.jsp"; }

39. Location of JSP protected String jspLocation(String page) { return "/ch3/dataBean/" + page; }

40. Location of JSP - New Way if (request.getParameter("processButton") != null) { address = "Process.jsp"; } else if (request.getParameter("confirmButton") != null) { address = "Confirm.jsp"; } Else { address = "Edit.jsp"; } address = jspLocation(address);

41. Visible and Hidden JSP Visible – /homework3/jsp/ Hidden – /WEB-INF/homework3/jsp/ WEB-INF is hidden from the browser not the servlet

42. JSP Location - MORE If jsp is at the same location of the class – “/WEB-INF/classes/mypackage/myclass/” + page Where to keep the JSPs pages? – Keep it hidden to yield to the controller.

43. JSP LOCATION - MORE If you are single developer – You may want to keep the jsp in the same location that you have your controller – Starting chapter 4, the book will follow this method. If you are working in a team or want to keep things organized – Keep JSP in separate folders

44. Controller Logic - MORE Controllers need to perform several task – Save/Load Data – Validate Data – Set address of next page – … To keep things more organized – Use a method for each button – Use annotations to specify the button

45. Decoding Button Names @ButtonMethod(buttonName = “confirmButton“) public String confirmButton() { fillBeanFromRequest(data); String address; if (isValid(data) ){ address = “Confirm.jsp”; } else { address = “Edit.jsp”; } return jspLocation(address); }

46. Buttons & Annotations Use isDefault=True parameter for the default button – @ButtonMethod(buttonName=“editButton”, isDefault=true) – Even if no button is clicked, this will be the default action Make sure the annotation reflects the name of the method and button

47. Executing the button Call executeButtonMethod() Call executeButtonMethods(Class clazz, boolean searchForDefaults) Call InvokeButtonMethod(Method buttonMethod)

48. protected String executeButtonMethod(Class clazz, boolean searchForDefault) throws IllegalAccessException, InvocationTargetException { String result = ""; Method[] methods = clazz.getDeclaredMethods(); for (Method method : methods) { ButtonMethod annotation = method.getAnnotation(ButtonMethod.class); if (annotation != null) { if (searchForDefault && annotation.isDefault()) { methodDefault = method; } if (request.getParameter(annotation.buttonName()) != null) { result = invokeButtonMethod(method); break; }

49. In-Class participation Due June 14: please write pseudo-code and comments explaining how the button invocation works. This includes the following methods from HelperBaseCh4 – Call executeButtonMethod() – Call executeButtonMethods(Class clazz, boolean searchForDefaults) – Call InvokeButtonMethod(Method buttonMethod) It will be only be accepted late during the day of June 14. It must be handed to me before the end of my office hours.

50. Filling a bean Can we automate the mutators methods for the bean? – void setPlayerName(string playerName) We can use a java extension to do this Remember to follow the name conventions – playerName will be? setPlayerName(….) getPlayerName()

51. What do you need? commons-collection – Version used in book: 3.2.1 commons-logging – Version used in book: 1.1.1 commons-beanutils – Version used in book: 1.8.3 Download from the book site (jar) or – htttp://jakarta.apache.org/common/

52. fillBeanFromRequest public void fillBeanFromRequest(Object data) { try { populate(data, request.getParameterMap()); } catch (IllegalAccessException iae) { logger.error("Populate - Illegal Access.", iae); } catch (InvocationTargetException ite) { logger.error("Populate - Invoke Target.", ite); }

53. Using fillBeanFromRequest @ButtonMethod(buttonName=“confirmButton ”) Public String confirmMethod() { fillBeanFromRequest(data); return jspLocation(“Confirm.jsp”) }

54. ControllerHelper – doGet() protected void doGet() throws ServletException, IOException { addHelperToSession("helper", SessionData.READ); String address = executeButtonMethod(); RequestDispatcher disp = request.getRequestDispatcher(address); disp.forward(request, response); }

55. Where to place the files !

56. Notes Review the code in pages 130 and 131 of your book

57. Office Hours Remember that I switch my office hours for Tuesdays.