1. © MIT 2000 Building Web Applications With Webjects Michael D. Barker The MIT Educational Media Creation Center September 2001

2. © MIT 2001 What's a Webject? n A set of servlets, allowing handling of several "standard" operations on data over the web by setting up the correct forms and configuration files. Notice that I did not say writing code – the servlets are deliberately designed to be generic, so that changes are made in the forms and configuration files, not the code. n At this point in time, there are five webject servlets: Capture, Lister, Displayer, Revise, and Deleter. n Webject as a one set of data.

3. © MIT 2001 Capture HTML Form Capture Servlet Webject List Capture is used to collect information from a web form for ONE webject. Often, the web form is just a simple html page, with form action posting to capture.

4. © MIT 2001 Lister HTML Form Lister Servlet Webject List Lister generates a web form displaying information from all the webjects in a list. HTMX Form

5. © MIT 2001 Displayer HTML Form Displayer Servlet Webject List Displayer generates a web form displaying information from a single webject. HTMX Form

6. © MIT 2001 Revise HTML Form Revise Servlet Webject List Revise is used to collect information from a web form to make changes for ONE webject. Often, the web form is generated by displayer.

7. © MIT 2001 Deleter HTML Form Deleter Servlet Webject List Deleter is used to remove one webject from the list. Often, it is invoked from a form generated by lister.

8. © MIT 2001 Typical Application n Collect information (using Capture) n Display a list of results (using Lister) n With edit buttons (using Displayer) that bring up forms whose submit changes the information (using Revise) n And delete buttons (that bring up a form and confirm, then invoke Deleter)

9. © MIT 2001 Parameters, XML files, and such n Every servlet has some parameters. n webject specification file n webject list file n Configuration in servlet zone properties file n page templates (htmx files)

10. © MIT 2001 Webject Specification File <parameter name="term" required="1" errorRequired="You must provide a term to be defined." /> <parameter name="definition" required="1" errorRequired="You must provide a definition for the term." /> Replace the parameter definitions with your data fields.

11. © MIT 2001 Possible Attributes Among the attributes that can be specified for a parameter are: n name="name" The name of the parameter. Required. n required="1" n errorRequired="message" n optional="1" (default) n ignored="1" (discard even if value present – good for discarding submit) n multiple="1" May have multiple values n default="value" n equals="name" use value of name n defaultequals="name" use value of name as default

12. © MIT 2001 Webject List File <iplist type="iprange" specfile="../conf/iplistspec.xml" docclass="edu.mit.emcc.webject.WebjectList" webjectclass="edu.mit.emcc.webject.Webject"> 1

13. © MIT 2001 HTMX File n Normal HTML plus (Displayer and Lister) n : the value of name n : CHECKED if non-blank value n : SELECTED if value (Lister only) n : number of items in list n... : repeat for all elements in list

14. © MIT 2001 Capture Parameters Minimum: n servlet.AddTicket.code=edu.mit.emcc.webject.Capture (alias) n servlet.AddTicket.initArgs=root=/development (root directory to prepend to all other file names) n servlet.AddTicket.initArgs=capturepage=ListTickets or servlet.Register.initArgs=capturepage=../lobby/register. html (html form, allows gets to servlet to redirect to form) n servlet.AddTicket.initArgs=webjectlist=data/ccoach/ac cessinfo/tickets.xml (the webject list)

15. © MIT 2001 Capture Parameters Additional: n servlet. SomeName.initArgs=templatedir= Directory where HTML templates are stored n servlet. SomeName.initArgs=successtemplate= for successful submissions (default: capturesuccess.htmx) n servlet. SomeName.initArgs=errortemplate= for validation errors (captureerror.htmx) n servlet. SomeName.initArgs=duplicatetemplate= for duplicate keys (captureduplicate.htmx) n There is also a set of parameters to generate email – read the code for details (list follows)

16. © MIT 2001 Capture Parameters (email) n servlet.SomeName.initArgs=mailserver=(address) n servlet.SomeName.initArgs=partialemailtemplate=(filename) n servlet.SomeName.initArgs=partialto=(address) n servlet.SomeName.initArgs=partialsubject=(subject) n servlet.SomeName.initArgs=partialfrom=(address) n servlet.SomeName.initArgs=completeemailtemplate=(filename) n servlet.SomeName.initArgs=completeto=(address) n servlet.SomeName.initArgs=completesubject=(subject) n servlet.SomeName.initArgs=completefrom=(address)

17. © MIT 2001 Lister Parameters Minimal n servlet.SomeName.code=edu.mit.emcc.webject.Lister (alias) n servlet. SomeName.initArgs=projectroot= (root of files) n servlet. SomeName.initArgs=webjectlist= (data list) n servlet. SomeName.initArgs=templatedir= (where are the templates)

18. © MIT 2001 Lister Parameters Optional n servlet. SomeName.initArgs=listtemplate= Defaults to listtemplate.htmx n servlet. SomeName.initArgs=mimetype= Defaults to text/html n servlet. SomeName.initArgs=sortby= Defaults to date n servlet. SomeName.initArgs=daysback= How many days back to include (defaults to all) Often entered in url (servlet name?daysback=5 for example)

19. © MIT 2001 Displayer Parameters Minimal n servlet.SomeName.code=edu.mit.emcc.webject.Displayer (alias) n servlet.SoName.initArgs=projectroot= (root for files) n servlet.SoName.initArgs=webjectlist= (data list) n servlet.SoName.initArgs=templatedir=

20. © MIT 2001 Displayer Parameters Optional n servlet.SoName.initArgs=webjecttemplate= Defaults to webjecttemplate.htmx n servlet.SoName.initArgs=notfoundtemplate= Defaults to notfoundtemplate.htmx n servlet.SoName.initArgs=idsource= How to get id of webject. Defaults to parameter (ID=xxx). Also accepts auth (look up user in webject list) and username (a username parameter will be supplied)

21. © MIT 2001 Revise Parameters Minimal n servlet.SomeName.code=edu.mit.emcc.webject.Revise (alias) n servlet.SoName.initArgs=projectroot= n servlet. SoName.initArgs=editpage= n servlet. SoName.initArgs=webjectlist= n servlet. SoName.initArgs=templatedir=

22. © MIT 2001 Revise Parameters Optional n servlet. SoName.initArgs=successtemplate= Defaults to revisesucess.htmx n servlet. SoName.initArgs=errortemplate= Defaults to reviseerror.htmx

23. © MIT 2001 Deleter Parameters Minimal n servlet.SomeName.code=edu.mit.emcc.webject.Deleter (alias) n servlet.SoName.initArgs=projectroot= n servlet.SoName.initArgs=webjectlist= n servlet.SoName.initArgs=templatedir= Runtime n SomeName?ID=xxxxx Or SomeName?id=xxxxxx

24. © MIT 2001 Deleter Parameters Optional n servlet. SoName.initArgs=deletedtemplate= Defaults to deletedtemplate.htmx

25. © MIT 2001 Likely Future Additions to the Webject Library n "archive" – put a class of webjects into another file and remove from the "active" file n Conversion to use mySQL, Oracle, or other database

26. © MIT 2001 For Additional Information n Brian Bermack's original documentation

27. © MIT 2001 You Can Reach Us... n Michael Barker –mbarker@mit.edu –617/253-0119 n EMCC website: http://web.mit.edu/emcc/