[cvs] expresso commit by mtraum: tutorial has been updates and
moved to
JCorporate Ltd
jcorp at jcorporate.com
Thu Mar 17 06:15:27 UTC 2005
Log Message:
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tutorial has been updates and moved to weblog example application
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-<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
-<html lang="en">
-<head>
-<meta http-equiv="Content-Type" content="text/html;charset=ISO-8859-1">
-<link href="/style/default.css" rel="stylesheet" type="text/css">
-<title>Expresso Tutorial: WebLog Application</title>
-<META name="robots" content="all">
-<base href="http://www.jcorporate.com">
-</head>
-
-<BODY vlink="#0000ff" alink="#cc0000" link="#0033ff" bgcolor="#ffffff" class="jc-default">
-<div class=Section1>
- <h1 align="center">Expresso Tutorial</h1>
- <h4 align="center">Using WebLog Application</h4>
-
- <TABLE border="0" width="100%">
- <TBODY>
- <TR>
- <TD width="14%" valign="top">
- <H4>Version:</H4>
- </TD>
- <TD width="42%" valign="top">
- <P>Expresso 5.x</P>
-
- </TD>
- <TD width="12%" valign="top">
- <H4>Author:</H4>
- </TD>
- <TD width="32%" valign="top">
- <P><A href="mailto:tdai at optonline.net?Subject=WebLog Tutorial">Tino Dai</A>, <A href="mailto:dlloyd at jgroup.net?Subject=WebLog Tutorial">David Lloyd</A></P>
- </TD>
- </TR>
-
- </TBODY>
- </TABLE>
- <p class="jc-explanation">So your doing server side development? You’ve
- already determined that developing using a MODEL-VIEW-CONTROLLER design pattern
- is the way to go you. Your dilemma is you are under tight time constraints
- for your project. Maybe even you are new to Java and feel daunted by its
- complexity at the moment. As a seasoned developer you know that starting
- a new application from scratch is not the best strategy in the time-to-market
- philosophy of the real business world. You want to leverage existing code. </p>
- <p>With advances in studio products, the ready-made web application is on the
- horizon, where you as a software developer, will look in distaste if you
- had to code your own security, database persistence layers, session management,
- controller, actions, input and output, validation, and user profiling entirely
- from scratch. Hence the reason you want to learn more about frameworks. </p>
- <h2>Introduction</h2>
- <p>I am presenting this tutorial because it is my view that frameworks can
- have a steep learning curve because of their complexity. Expresso Framework
- for example has well over 200 classes. So this tutorial is aimed at making
- it easier to get going.</p>
-
- <p>Although there are a number of architectural frameworks, I am going to present
- this tutorial for the open source Expresso Framework ( <a
-href="http://www.jcorporate.com/">www.jcorporate.com</a>) which is a popular
- project with a large user base. The Expresso application has been around
- since 1999, during which it has matured into a robust application being used
- in both large and small companies. The framework is based on the Jakarta
- Struts framework, and extends it to create a full featured framework complete
- with built-in security, MVC architecture, and a whole host of other features.</p>
- <h2>Section I: What Comprises Expresso?</h2>
- <p>Expresso is divided technically into for parts: database object persistence,
- controller design, schemas, and the rest of the toolkit which involves job
- control, utilities etc. It is essential that you understand the first three
- parts. My tutorial will help you with this using a simple web log application.</p>
- <h3>Database Object Persistence</h3>
- <p> Object to Relation mapping or O/R mapping for short is one
- of the foundations of Expresso. All O/R mapping means is the relating of
- relations database elements to plain old Java objects. In Expresso, they
- are called DBObjects. Expresso supports many of the most popular databases
- such as Oracle, Mysql, Sybase, and SQL Server through DBObjects. This particular
- set of DBObjects can be found in <em>com.jcorporate.expresso.core.dbobj</em>.
- The DBObjects work by abstracting the JDBC calls and putting the values into
- a Java object. The DBObject provides an intermediate object for the application
- to interact with the database. This allows for the developer to worry about
- the application code and not have to directly manage the connection pool
- and/or the JDBC calls. From the DBObject class, there are several subclasses
- that are worth mentioning. </p>
-
- <table width="100%" border="0">
- <tr valign="top">
- <td bgcolor="#91acdb"><span class="jc-default">SecureDBObject:</span> </td>
- <td> </td>
- <td class="jc-default">DBObjects that have Expresso security built right in</td>
- </tr>
- <tr valign="top">
-
- <td bgcolor="#91acdb" class="jc-default">MediaDBObject: </td>
- <td> </td>
- <td class="jc-default"> DBObjects that allows non-text (or blobs) field in the DBObject's
- fields</td>
- </tr>
- <tr valign="top">
- <td bgcolor="#91acdb" class="jc-default">RowDBObject:</td>
- <td> </td>
-
- <td class="jc-default">DBObjects that allow for row level locking (instead of table level
- locking as with the regular DBObjects)</td>
- </tr>
- </table>
- <p>Of the three DBObjects above, the tutorial will be using SecuredDBObject
- heavily in the next section. The next section will explain how to manipulate
- the DBObjects using controllers.</p>
- <h3>Controller</h3>
- <p> The engine of Expresso is the controller and can basically
- be thought of as a finite state machine with inputs, outputs, transitions,
- and blocks with security built right in. The controller will migrate from
- state to state performing the actions of that state. The controller will
- use inputs to take values from external sources such as keyboard. It will
- utilize outputs to convey information back to the user. The controller relies
- on transitions to move from state to state. The block serves as a container
- in which a controller can store many inputs, outputs, and transitions. This
- makes for easier coding and maintenance of the code. Expresso has security
- that filters down into the controller. This permits or denies access to one
- or more of the controllers' states. As with the DBObjects, Expresso has a
- set of controllers that can be used with little or no modification. DBMaint
- is one of these pre-made controllers and can be found in com.jcorporate.expresso.services.
- This controller will be used heavily in the tutorial to provide the basic
- Add, Delete, Update, and Search functions for any SecuredDBObject. I choose
- to use the DBMaint for two reasons: first to not reinvent the wheel and second
- to provide you with tools to accelerate your own development. </p>
-
- <h3>Schema</h3>
- <p> The schema in Expresso can be though as the “announcer” for
- the application. The schema class is called when the application is brought
- into the Expresso environment. In this class, two sections will be focused
- on. The first section is the constructor which will encapsulate all the components
- to be added such as DBObjects, controllers, and jobs. The other section
- is the different security parameters on each component, or in other words:
- who gets access to what and what kind of access.</p>
- <p> The three concepts described above: DBObjects, controllers,
- and Schema should give you an understanding of the mechanisms behind Expresso.
- I will use this as a foundation to explain my code.</p>
- <h2>Section II: How Do I Get Started?</h2>
- <p> I talked about what Expresso is and a sprinkling of theory
- behind it. I will be applying the theory to working code in this section
- to give you an illustration of the power of Expresso via a Weblog application.
- First, we will look at the complete architecture of the Weblog (as shown
- below:</p>
-
- <p align="center"><img width=450 src="/images/doc/tutorial/image002.jpg"></p>
- <p><span class="jc-label">Diagram #1:<br>
- The picture gives a view of how all components are tied together.
- The controllers access the DBObject (in this case SecuredDBObjects) and push
- the resulting controller values out to the JSPs. So, how does one write the code
- to do this? </span> <br clear=ALL>
- </p>
- <p> The DBObjects are the foundation on which Expresso
- is built. SecuredDBObjects are used in this tutorial for their security properties.
- So, what does a DBObject look like? Below is two code snippet from the Entry
- DBObject of the declaration and setupFields method.</p>
- <p class="jc-code"> public class Entry extends SecuredDBObject { (1)</p>
-
- <p>(1) The declaration of this class extends
- the SecuredDBObject class</p>
- <p class="jc-code"> protected synchronized void setupFields ()
- throws DBException{ <br>
- (1) setTargetTable("WLOGENTRY"); <br>
- (2) addField(FLD_ENTRY_ID,"auto-inc",
- 0, false, "Entry
- ID");<br>
-
- (3) addField(FLD_USER,"int",30,false,"User
- Name"); <br>
- (4) addField(FLD_DATE,"datetime",0,false,"Date
- and Time"); <br>
- (5) addField(FLD_TITLE,"varchar",30,false,"Title"); <br>
-
- (6) addField(FLD_ENTRY,"text",0,true,"Entry"); <br>
- (7) setReadOnly(FLD_USER); <br>
- (8) setReadOnly(FLD_DATE); <br>
- (9) addKey(FLD_ENTRY_ID);
- <p class="jc-code"> }</p>
- <p class="jc-label">(1) The <span class="jc-code">setTargetTable</span> will tell which database table this particular DBObject
- will be working on</p>
-
- <p class="jc-label">(2-6) The <span class="jc-code">addField</span> adds a field to the database. The syntax of the addField
- is </p>
- <p class="jc-code">addField(Field name, type, max characters, whether or not the field can
- be empty,Field description)</p>
- <p class="jc-label">(7-8)The <span class="jc-code">setReadOnly</span> field allows the DBMaint by pass that field. It's a
- little confusing now, but it will become more clear</p>
- <p class="jc-label">(9) The <span class="jc-code">addKey</span> allows a field to become the primary key in the database.</p>
-
- <p>The DBObject will translate into a table like the one shown below below.
- I used mySQL in this tutorial for illustration.</p>
- <p><span class="jc-code">mysql> desc WLOGENTRY</span>;</p>
- <p class="jc-code">+---------------+-------------+------+-----+---------------------+-------+</p>
- <p class="jc-code">| Field | Type | Null | Key | Default |
- Extra |</p>
- <p class="jc-code">+---------------+-------------+------+-----+---------------------+-------+</p>
-
- <p class="jc-code">| EntryID | int(11) | | PRI | 0 | |</p>
- <p class="jc-code">| UserLoginName | int(30) | | | 0 | |</p>
- <p class="jc-code">| EntryDate | datetime | | | 0000-00-00 00:00:00 | |</p>
- <p class="jc-code">| Title | varchar(30) | | | | |</p>
- <p class="jc-code">| EntryText | text | YES | | NULL | |</p>
- <p class="jc-code">+---------------+-------------+------+-----+---------------------+-------+</p>
-
- <p class="jc-code">5 rows in set (0.00 sec)</p>
- <p> In the next paragraph, there will be controller code illustrating
- the use for both business logic and to manipulate DBObjects.</p>
- <p> The controllers are the engine of Expresso. I will be using
- the <span class="jc-code">DBMaint</span> and the <span class="jc-code">SimpleLogin</span> controllers which are pre-made controllers.
- The tutorial will be extending those. There will be several code snippets
- to illustrate the mechanisms behind a controller. The first code snippet
- shows the constructor. The controller's constructor sets up the different
- states within the controller.</p>
- <p> <span class="jc-code">public WlogLogin() {<br>
-
- super(); (1)<br>
- // some other stuff here ...<br><br>
-
- State promptCreate = new State("addUser","Adding Users..."); (2)<br>
- addState(promptCreate); (3)<br>
- State processCreate = new State("processNewUser","Processing New Users");<br>
- addState(processCreate);<br>
- }</span>
- <P align="center"> <img width=575 height=256 src="/images/doc/tutorial/image004.jpg" ></P>
- <p>(1)The super will initialize the base class; initializing any states, security, etc. as needed.</p>
- <p>(2)A new state called <span class="jc-code">addUser</span> is being created.</p>
-
- <p>(3)The <span class="jc-code">addState</span> adds the new state to the possible states that this particular
- controller can transition to</p>
- <p>Once the constructor has been set up, the actual states need to be set up. But
- before leaving this topic of controller constructors, there is a critical
- method called <span class="jc-code">addDefaultState</span> which must be in the constructor. Its purpose
- is to provide a default state to transition to if none is given eg. <a
-href="http://localhost:8080/weblog/WlogLogin.do">http://localhost:8080/weblog/WlogLogin.do</a>.
- Below is a state from the <span class="jc-code">WlogLogin</span> class.</p>
-
- <p> <span class="jc-code">protected void runAddUserState(ControllerRequest req, ControllerResponse
- res) throws ControllerException {<br>
- res.addInput(new Input("UserName","User Name"));<br>
- res.addInput(new Input("Password","Password"));<br>
- res.addInput(new Input("RePassword","Re Password"));<br>
-
- res.addInput(new Input("Email","Email Address"));<br>
- res.addTransition(new Transition("myButton", "Add User", WlogLogin.class, "processNewUser"));<br>
- }</span><br clear=all style='page-break-before:always'>
- </p>
- <p>The method names must be in the following fashion for the method to be a
- valid state.</p>
-
- <h5 align=center style='text-align:center;'>Run + Controller State's Name +
- State</h5>
- <p>Anything that doesn't follow this pattern is just another method. Also like
- the Java convention, the controller name should be <span class="jc-code">runExampleControllerState</span> with the first letter of the second word capitalized in this case Example.
- The <span class="jc-code">ControllerRequest</span> and <span class="jc-code">ControllerResponse</span> are parameters that hold values
- between the states. In the above code, the res parameter being assigned news
- values: 4 inputs and 1 one transition. In diagram #2, after a state is processed,
- it is passed to the jsp to render. If there is no jsp, then Expresso uses
- it's own rendering system. In this case, we are using the Expresso rendering
- system, and looks like so:</p>
- <p>The picture shows the inputs as text boxes and the transition as a button.
- The next state is the <span class="jc-code">runProcessNewUserState</span> (see above code: <span class="jc-code">addTransition</span> statement). The <span class="jc-code">runAddUserState</span> is a less complex controller. The <span class="jc-code">runListBothState</span> controller is a more complex controller.</p>
-
- <p> The <span class="jc-code">listBoth</span> controller is part of the CommentDBMaint class.
- The <span class="jc-code">CommentDBMaint</span> class is a extension of the pre-made DBMaint.</p>
- <p class="jc-code">protected void runListBothState(ControllerRequest
- req, ControllerResponse res) throws ControllerException, DBException { (1)<br>
- ArrayList commentArray = new ArrayList(); <br>
- Entry entryDBObj = new Entry(); (2)<br>
-
- Comment commentDBObj = new Comment(); (3)<br>
- entryDBObj.setField(FLD_ENTRY_ID,req.getParameter("entryid"));
- (4)<br>
- entryDBObj.find(); (5)</P>
- <p>(1) Here again the reader sees an ordinary method become a state with the
- <span class="jc-code">ControllerRequest</span> and <span class="jc-code">ControllerResponse</span> parameters</p>
-
- <p>(2-3) In the theory section, it was mention that DBObjects could be treated
- like another object, and here the Entry and Comment DBObjects are being instantiated </p>
- <p>(4) This <span class="jc-code">setField</span> allows the field <span class="jc-code">EntryID</span> in the Entry DBObject to take
- on the value of <span class="jc-code">req.getParamete(“entryid”)</span></p>
- <p>(5) The <span class="jc-code">entryDBObj.find()</span> will go into the underlying database and retrieve
- all of the entries. The find method can be limited by setting one of more
- fields within the DBObject to a certain value. In this cases, the find will
- only return the records that match the value in the <span class="jc-code">EntryID</span> field.</p>
-
- <p class="jc-code"> Block b1 = new Block("b1"); (6)<br>
- b1.add(new Output(FLD_USER,entryDBObj.getField(FLD_ENTRY_ID)));
- (7)<br>
- b1.add(new Output(FLD_DATE,entryDBObj.getField(FLD_USER))); (8)<br>
- b1.add(new Output(FLD_TITLE,entryDBObj.getField(FLD_TITLE))); (9)<br>
- b1.add(new Output(FLD_ENTRY,entryDBObj.getField(FLD_ENTRY))); (10)<br>
-
- res.addBlock(b1); (11)<br>
- <p>(6-11) Here we see an example of a creation of a new block, adding of the
- new components to the block, and adding of the block to the <span class="jc-code">ControllerResponse</span> parameters. </p>
- <p> <span class="jc-code">commentDBObj.setField(CMT_ENTRY_REF,req.getParameter("entryid"));(12)<br>
- commentArray = commentDBObj.searchAndRetrieveList(); (13)<br>
-
- Iterator e = commentArray.iterator(); (14)<br>
- Comment commentTemp = new Comment(); (15)<br>
- Block b2 = new Block("b2"); (16)<br>
- while ( e.hasNext() ) { (17)<br>
- commentTemp = (Comment)e.next(); (18)<br>
- Block oneRow = new Block("oneRow"); (19)<br>
- oneRow.add(new Output(commentTemp.getField(CMT_USER))); (20)<br>
-
- oneRow.add(new Output(commentTemp.getField(CMT_DATE))); (21)<br>
- oneRow.add(new Output(commentTemp.getField(CMT_TITLE))); (22)<br>
- oneRow.add(new Output(commentTemp.getField(CMT_COMMENT)));(23)<br>
- b2.add(oneRow); (24)<br>
- }<br>
- res.addBlock(b2); (25)</span><br>
- <p>(12-25) This block of code will retrieve all of the rows pertaining to the
- particular Entry DBObjects that was retrieved above. The readers sees the
- <span class="jc-code">searchAndRetrieveList</span> method. This retrieve all the rows in the database
- and transfers them to an <span class="jc-code">ArrayList</span>. The <span class="jc-code">ArrayList</span> is then iterated to to
- retrieve each row's information. What is interesting about this snippet of
- code is there is a series of blocks (oneRow) inside of another block (b2).
- In a later section, it will be illustrated how to extract the information
- from a block within a block</p>
-
- <p> <span class="jc-code">Block transBlock = new Block("transBlock"); (26)<br>
- Transition b3 = new Transition("listEntry","List Weblog
- \ Entry",com.jcorporate.demo.weblog.controller.EntryDBMaint.class,"List" (27)<br>
-
- b3.addParam("dbobj",com.jcorporate.demo.weblog.dbobj.Entry.class.getName());(28)<br>
- transBlock.add(b3); (29)<br>
- b3 = new Transition("addEntry","Add Weblog \ <br>
- Entry",com.jcorporate.demo.weblog.controller.EntryDBMaint.class,"Add”);(30)<br>
-
- b3.addParam("dbobj",com.jcorporate.demo.weblog.dbobj.Entry.class.getName());(31)<br>
- transBlock.add(b3); (32)<br>
- b3 = new Transition("logout","Logout", \<br>
- com.jcorporate.demo.weblog.controller.WlogLogin.class, "processLogout");
- (33)<br>
-
- transBlock.add(b3); (34)<br>
- res.addBlock(transBlock); (35)<br>
- }</span></p>
- <p>(26-35) This snippet is creating a block that will have a series of transition
- components. The transition will have a syntax of:</p>
- <p class="jc-code">transition(name,description,what controller to transition to, what controller
- state to transition to)</p>
- <p>Also the there is an <span class="jc-code">addParam</span>. This allows one to tack on parameters to
- the transition. In this case it is the DBObject that the state will be interacting
- with. Without the <span class="jc-code">addParam</span>, the transition will throw an error because it
- doesn't know where to transition to. And finally, the block is added to the
- <span class="jc-code">ControllerResponse res</span>.</p>
-
- <p> In the diagram #2, there is a <span class="jc-code">WeblogSchema</span> class. The
- <span class="jc-code">WeblogSchema</span> classes acts as a registration mechanism to make Expresso aware
- of the different components in the target application, and a way to setup
- any other sort of initialization, in this case security. Below we see a
- snippet of code that allows, in this case, two controllers and two DBObjects
- to be added.</p>
- <p> <span class="jc-code">public WeblogSchema() {<br>
- super();<br>
- addDBObject(com.jcorporate.expresso.demo.weblog.dbobj.Entry.class);<br>
-
- addDBObject(com.jcorporate.expresso.demo.weblog.dbobj.Comment.class);<br>
- addController(com.jcorporate.expresso.demo.weblog.controller.EntryDBMaint.class);<br>
- addController(com.jcorporate.expresso.demo.weblog.controller.CommentDBMaint.class);<br>
- addController(com.jcorporate.expresso.demo.weblog.controller.WlogLogin.class);<br>
- }</span></p>
- <p>The mechanism for adding the DBObjects, controllers, and other various items
- is done by calling the appropriate method from the class constructor (<span class="jc-code">WeblogSchema</span>).
- The methods have a standard name: add + component type for example: to add
- a DBObject, it is addDBObject(classname) . Schema class's <span class="jc-code">otherSetup</span> method
- is used to setup security for the DBObjects and the controllers. Below is
- part of the <span class="jc-code">otherSetup</span> method found in the <span class="jc-code">WeblogSchema</span>.</p>
-
- <p> <span class="jc-code"> public void otherSetup(String DBName) throws
- DBException {<br>
- UserGroup user = new UserGroup();<br>
- String oneString;<br>
- user.setRequestingUid(SecuredDBObject.SYSTEM_ACCOUNT); (1)<br>
- user.setDataContext(this.getDBName()); (2)<br>
- user.setField("GroupName",WLOG_ADM); (3)<br>
-
- user.setField("Descrip","Weblog II Admin"); (4)</span></p>
- <p>(1)This gives who is request access to the database</p>
- <p>(2)Specifies the database is being requested</p>
- <p>(3)Will set the field <span class="jc-code">GroupName</span> to <span class="jc-code">WeblogAdm</span></p>
-
- <p>(4)Will set the field <span class="jc-code">Descript</span> to “<span class="jc-code">Weblog
- II Admin</span>”</p>
- <p><span class="jc-code"> user.addIfNeeded(); (5)<br>
- user.clear(); (6)</span><br>
- <p>(5)The <span class="jc-code">addIfNeeded</span> instructs the DBObject to add the record only if needed
- or in other words only if the record doesn't already exist</p>
-
- <p>(6)The clear method will clear all of the <span class="jc-code">setField</span> parameters and allow
- the DBObject to act as if it was just instanshiated </p>
- <p> <span class="jc-code">user.setField("GroupName",WLOG_USER);<br>
- user.setField("Descrip","Weblog II User");<br>
-
- user.addIfNeeded();<br>
- GroupMembers group = new GroupMembers();<br>
- group.setField("GroupName",WLOG_ADM);<br>
- group.setField("ExpUid","4");<br>
- group.addIfNeeded();<br>
- group.clear();<br>
-
- group.setField("GroupName",WLOG_USER);<br>
- group.setField("ExpUid","4");<br>
- group.addIfNeeded();<br>
- GroupNest gnest = new GroupNest();<br>
- gnest.setField("GroupName",WLOG_ADM);<br>
-
- gnest.setField("MemberOf",WLOG_USER);<br>
- gnest.addIfNeeded();</span></p>
- <p>Here again DBObjects again come into play. The first DBObject that the reader
- encounters is <span class="jc-code">UserGroup</span>. </p>
- <p>This was just a snippet of the entire <span class="jc-code">otherSetup</span> method, to see all of the
- DBObjects are used, please refer to the source code located on the Jcorporate
- site.</p>
-
- <p> To display to a web browser, there are a multitude of languages/methods
- that one can use. In this case, JSPs are used to render. From <span class="jc-code">CommentDBMaint's
- listBoth</span> state:</p>
- <p> <span class="jc-code">Block b1 = <b>new</b> Block("b1");<br>
- b1.add(<b>new</b> Output(FLD_USER,entryDBObj.getField(FLD_ENTRY_ID)));<br>
-
- b1.add(<b>new</b> Output(FLD_DATE,entryDBObj.getField(FLD_USER)));<br>
- b1.add(<b>new</b> Output(FLD_TITLE,entryDBObj.getField(FLD_TITLE)));<br>
- b1.add(<b>new</b> Output(FLD_ENTRY,entryDBObj.getField(FLD_ENTRY)));<br>
- res.addBlock(b1);</span></p>
-
- <p >How does one extract this information
- from the b1 block? In the <span class="jc-code">cview.jsp</span>:</p>
- <p > <span class="jc-code"><table border="1" width="50%"> <br>
- <tr><br>
-
- <logic:iterate
- id="oneCol" property="b1"> (1)<br>
- <td><bean:write
- name="oneCol"/></td> (2)<br>
-
- </logic:iterate> (3)<br>
- </tr><br>
- </table></span></p>
- <p>(1)The JSP code is setting the b1 block created in the CommentDBMaint's
- <span class="jc-code">listBoth</span> state to the <span class="jc-code">oneCol</span> using the <logic:iterate> tag. </p>
-
- <p>(2)After the <span class="jc-code">oneCol</span> variable has been set, it can be written out to the
- web browser using the <span class="jc-code"><bean:write></span> tag. It is interesting to note that
- the <span class="jc-code"><bean:write></span> tag can handle input, outputs, transitions, as well
- as blocks.</p>
- <p>(3)Closing the <span class="jc-code"><logic:iterate></span> block</p>
-
- <p>Below is a more complex example: a block within a block. Again, there is
- a code snippet from the CommentDBMaint DBObj.</p>
- <p> <span class="jc-code">Block b2 = <b>new</b> Block();<br>
- <b>while</b> ( e.hasNext()
- ) {<br>
- commentTemp = (Comment)e.next();<br>
-
- Block oneRow = <b>new</b> Block("oneRow");<br>
- oneRow.add(new Output(commentTemp.getField(CMT_USER)));<br>
- oneRow.add(new Output(commentTemp.getField(CMT_DATE)));<br>
- oneRow.add(newOutput(commentTemp.getField(CMT_TITLE)));<br>
- oneRow.add(new Output(commentTemp.getField(CMT_COMMENT)));<br>
- b2.add(oneRow); <br>
-
- }<br>
- res.addBlock(b2);</span></p>
- <p >And another piece of the <span class="jc-code">cview.jsp:</span></p>
- <p > <span class="jc-code"><table border="1" width="50%"> <br>
-
- <logic:iterate id="oneRow" property="b2"> (1)<br>
- <tr><br>
- <logic:iterate id="oneCol" name="oneRow"> (2)<br>
-
- <td><bean:write name="oneCol"/></td> (3)<br>
- </logic:iterate> (4)<br>
- </tr><br>
- </logic:iterate> (5)<br>
-
- </table></span></p>
- <p >(1)The b2 block is set to oneRow
- using the <span class="jc-code"><logic:iterate></span></p>
- <p >(2)Remember that b2 has a block
- inside of it so there is another <span class="jc-code"><logic:iterate></span> to extract the information
- from <span class="jc-code">oneRow</span>.</p>
- <p >(3)After the information has been
- extract, it can be pushed out to the web browser with the <span class="jc-code"><bean:write></span> tag</p>
-
- <p >(4)This <span class="jc-code"></logic:iterate></span> closes
- the inner <span class="jc-code"><logic:iterate></span> tag</p>
- <p >(5)This <span class="jc-code"></logic:iterate></span> closes
- the outer <span class="jc-code"><logic:iterate></span> tag</p>
-
- <p >This is how the application gets
- the information from the controllers to the web browser using the JSPs.</p>
- <p> The final piece of the application is the <span class="jc-code">weblog-config.xml</span> file located in /WEB-INF/config/ directory. This will link together the different
- URIs to the different controllers and states that are available to the user. </p>
- <p> <span class="jc-code"> <?xml version="1.0" encoding="ISO-8859-1"?><br>
-
- <!DOCTYPE struts-config PUBLIC "-//Apache Software \ <br>
- Foundation//DTD Struts Configuration 1.0//EN"<br>
- "http://jakarta.apache.org/struts/dtds/struts-config_1_0.dtd"><br>
- <!-- For New Weblog --><br>
- <struts-config><br>
- <global-forwards><br>
-
- <forward name="logon" path="/weblog/WlogLogin.do"/><br>
- </global-forwards><br>
- <action-mappings><br>
- <action path="/weblog/EntryDBMaint" <br>
-
- type="com.jcorporate.expresso.demo.weblog.controller.EntryDBMaint" <br>
- name="default" scope="request" validate="false"><br>
- <forward name="List" \<br>
-
- path="/expresso/components/weblog/view.jsp"/><br>
- <forward name="Add" \<br>
- path="/expresso/components/weblog/add.jsp"/><br>
- <forward name="AddUpdate" \<br>
-
- path="/expresso/components/weblog/redirect.jsp"/><br>
- </action><br>
- <action path="/weblog/CommentDBMaint" <br>
- type="com.jcorporate.expresso.demo.weblog.controller.CommentDBMaint" <br>
- name="default" scope="request" validate="false"><br>
-
- <forward name="listBoth"<br>
- path="/expresso/components/weblog/cview.jsp"/><br>
- <forward name="Add"<br>
- path="/expresso/components/weblog/cadd.jsp"/><br>
-
- <forward name="AddUpdate"<br>
- path="/expresso/components/weblog/credirect.jsp"/><br>
- </action><br>
- <action path="/weblog/WlogLogin"<br>
- type="com.jcorporate.expresso.demo.weblog.controller.WlogLogin" name="default" <br>
-
- scope="request" validate="false"> (1)</span></p>
- <p>(1)This block of XML code states that if a URI comes in with the WlogLogin.do
- (in this case <a
-href="http://localhost:8080/weblog/WlogLogin.do">http://localhost:8080/weblog/WlogLogin.do</a>)
- then use the controller com.jcorporate.expresso.demo.weblog.controller.WlogLogin.
- If no state is given, then class will find it's default state and proceed
- to that one.</p>
- <p class="jc-code"> <forward name="promptLogin" \ <br>
-
- path="/expresso/components/weblog/login.jsp"/> (2)</p>
- <p>(2)The xml code's forward name refers to the state in that controller. In
- this case, the state would be promptLogin. And after performing that state's
- instructions, it will be passed to the /expresso/components/weblog/login.jsp
- for rendering.</p>
- <p class="jc-code"> <forward name="processLogin" \<br>
- path="/expresso/jsp/register/redirect.jsp"/> <br>
-
- <!-- <forward name="processLogout" \<br>
- path="/expresso/jsp/register/logout.jsp"/> --><br>
- <forward name="promptChangePassword"<br>
-
- path="/expresso/jsp/register/change.jsp"/><br>
- <forward name="processChangePassword"<br>
- path="/expresso/jsp/register/status.jsp"/><br>
- <forward name="emailValidate"<br>
-
- path="/expresso/jsp/register/status.jsp"/><br>
- <forward name="promptSendPassword"<br>
- path="/expresso/jsp/register/sendPassword.jsp"/><br>
- <forward name="processSendPassword"<br>
-
- path="/expresso/jsp/register/status.jsp"/><br>
- </action><br>
- </action-mappings><br>
- </struts-config></p>
-
- <p>For each controller in his/her application, there must be a action block
- like the one given above. Without it, the Expresso application will not run.</p>
- <br clear=all
-style='page-break-before:always'>
- <h2>Section III: Deploying the Application</h2>
- <p> The Execution section will cover the installation, security,
- and the day to day operations of the Expresso Weblog. The installation of
- the Weblog starts with the downloading of the weblog.war package. After one
- has downloaded the package, the reader should place it in the webapps directory of the container or otherwise cause
- it to be deployed in the container. If you are given the choice to have this application shared,
- you will probably want to <b>not</b> do so as it is preferable to keep the database separate from any other expresso
- implementation. In this tutorial, the author uses the Jakarta Tomcat
- 5.0.5 as the web container. </p>
- <p> A word of warning before we move on. The <a
-href="http://localhost:8080/Expresso">http://localhost:8080/Expresso</a> prefix
- works for my environment because my webroot is /Expresso. If you decide to
- use the Expresso complete package, to get to the main page, it would be <a href="http://localhost:8080/expresso/frame.jsp">http://localhost:8080/expresso/frame.jsp</a> instead
- of <a href="http://localhost:8080/Expresso/expresso/frame.jsp">http://localhost:8080/Expresso/expresso/frame.jsp</a>.
- Please keep that in mind as you go through the tutorial.</p>
-
- <p>This is the standard architecture for all Expresso applications. The WeblogSchema,
- in the com.jcorporate.expresso.demo.weblog package, is the key to bringing the
-application under the Expresso environment. The steps are:</div>
-<ol>
- <li>
- <div class=Section1>Go to: http://<where web container is located>/Expresso/expresso/frame.jsp. <br>
- <br>
- I will be using <a
-href="http://localhost:8080/Expresso/expresso/frame.jsp">http://localhost:8080/Expresso/expresso/frame.jsp</a> in
- this tutorial. (If you haven't logged in yet, then click on the login icon
- and log in as Admin)<br>
-
- <br>
- <img width=540 height=360 src="/images/doc/tutorial/image006.jpg"> <br>
- </div>
- </li>
- <li>
- <div class=Section1>
- <div class=Section1>The Application page will appear in the right hand
- frame. We will be using the Component Manager rather that the Registered
- Schema and Setup/Create Database route. Click on the Run Component Manager
- in the right frame. <br>
-
- <br>
- <img width=576 height=500 src="/images/doc/tutorial/image008.jpg"><br>
- </div>
- </div>
- </li>
- <li> You will be brought to the Component Manager Page. Click on the Add New
- Component button in the right hand frame.<br>
- <br>
- <img width=557 height=483 src="/images/doc/tutorial/image010.jpg"><br>
-
- </li>
- <li>In the text field, the reader would type: com.jcorporate.expresso.demo.weblog.WeblogSchema and
- click on Install Component. This will register the schema, build the tables
- in the underlying database, and setup security on the DBObjects and the controllers
- in the Expresso environment. <br>
- <br>
- <img width=557 height=483 src="/images/doc/tutorial/image012.jpg"><br>
- <br>
- <div class=Section1>Note: The WlogAdmin user is the administrator for the
- Weblog Application. The WlogAdmin user is generated in the Weblog installation.
- It's default password is default . Please remember to change it.<br>
-
- </div>
- </li>
- <li>To check if the Application is registered: Enter in the following in the
- Address field.<br>
- <br>
- <img width=575 height=271 src="/images/doc/tutorial/image014.jpg"><br>
- </li>
- <li>From that, the reader can login or he/she can choose to view the entries
- without logging in.
- <div class=Section1>After logging in, the following menu will appear.<br>
-
- <br>
- <img width=556 height=238 src="/images/doc/tutorial/image016.jpg"> <br>
- </div>
- </li>
- <li>
- <div class=Section1>If the reader clicks on the List:</div>
- <br>
- <img width=551 height=311 src="/images/doc/tutorial/image018.jpg"><br>
-
- This is the listing of the entries. The URI that was called was: <a
-href="http://localhost:8080/Expresso/EntryDBMaint.do?state=List&dbobj=com.jcorporate.expresso.demo.weblog.dbobj.Entry">http://localhost:8080/Expresso/EntryDBMaint.do?state=List&dbobj=com.jcorporate.expresso.demo.weblog.dbobj.Entry<br>
- <br>
- </a>
- <div class=Section1>When the web browser calls a specific URI like this,
- the Expresso framework checks the wlog-config.xml file to see if there
- is any jsp associated with this. In this case, there is a view.jsp associated
- with this state. The view.jsp will render the EntryDBMaint's list states
- output.</div>
- <br>
- </li>
- <li>
-
- <div class=Section1>If the reader clicks on Add in #9, he/she will see this:<br>
- <br>
- <img width=396 height=415 src="/images/doc/tutorial/image020.jpg"><br>
- <br>
- Unlike the one above, this has no jsp rendering associated with it. Instead,
- Expresso has its own rendering system. </div>
- </li>
-</ol>
-<div class=Section1>
- <h2>Conclusion</h2>
-
- <p>This wraps up the Expresso Weblog tutorial. In this tutorial, the author
- went over the theory, coding, and the execution of the Expresso Weblog. And
- in this tutorial, the author has given the tools to accelerate production
- such as the DBObjects and the built-in security within the Expresso environment.
- From here, if the reader is interested in delving more into the Expresso
- framework, there is a whole host of documents on the Expresso site (<a
-href="http://www.jcorporate.com/">http://www.jcorporate.com</a>) going into specific
- detail about the different facets of the framework. </p>
- <p>If the reader has any feedback: please email me at: <a href="mailto:tdai at optonline.net">tdai at optonline.net</a> or <a href="mailto:dlloyd at jgroup.net">dlloyd at jgroup.net</a></p>
- <p>Tino Dai is a development project manager.</p>
- <p>David Lloyd is an Expresso Core Contributor and provides expert consulting and development contracts through Jcorporate's Jgroup Services.</p>
- <DIV align="center">
- <hr>
- </DIV>
-
- <P><FONT color="#666666" size="2" face="Arial, Helvetica, Verdana"><FONT color="#666666" size="1" face="Arial, Helvetica, Verdana"><FONT size="2" face="Arial, Helvetica, Verdana" color="#000000"><FONT color="#000000">Copyright © 2002-2003</FONT> <A href="http://www.jcorporate.com/" target="_blank">Jcorporate
- Ltd</A>. All rights reserved.</FONT><FONT size="2" face="Arial, Helvetica, Verdana"><FONT color="#ffcc33"> <A href="http://www.jcorporate.com/html/aboutus/copyright.htm">Copyright</A> <A href="http://www.jcorporate.com/html/aboutus/privacy.htm">Privacy</A></FONT></FONT></FONT></FONT><FONT color="#666666" size="1" face="Arial, Helvetica, Verdana"><FONT color="#666666" size="1" face="Arial, Helvetica, Verdana"><FONT size="2" face="Arial, Helvetica, Verdana"><FONT color="#ffcc33"><A href="http://www.jcorporate.com/html/aboutus/privacy.htm"><BR>
- </A></FONT></FONT><FONT face="Arial, Helvetica, Verdana" color="#666666" size="1"><BR>
- Last Modified:
- <!-- #BeginDate format:En2 -->11-Sep-2003<!-- #EndDate -->
- </FONT></FONT></FONT></P>
-
- <p> </p>
-</div>
-</body>
-</html>
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