OBEROn - Tutorial - Perform user functions on web applications

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perform user functions on web applications

Java Server Pages (JSP) combine HTML, JavaScript, and Java code and provide a simple programming method to display and dynamically update content on Web pages. They lets you create complex client/server applications for the Web through the dynamic substitutions within an HTML page.
The following examples show how to implement some basic function with JSP pages.

NOTE: for old versions before the 4.0, it's very important to note that if the application server connects to the database indirectly through a HTTP / RMI interface all java API methods with the "framework" input argument don't work properly. In this case (iit is a best practice to do it always) you MUST use the JRClient class methods to perform the operations.

doLogin.jsp

This JSP page performs the login to OBEROn for the username and password passed as input parameters from the login page and generates the application menu with all commands available for the framework user.
The html code for the navigation menu is stored into a session attribute and it doesn't change until the user re-logins to the system. Moreover, the menu-command labels are translated to the browser language if their translations are defined into the OBEROn dictionary.

It is very important to note the setting: framework.setRenderingEngine("HTML");
this parameter included into the framework informs the generic user interface level that current user is connecting through a web interface; you can implement some filters to enable / disable application functionality according to this fact.

<%@include file ="library.jsp"%>
<%

session.setAttribute("RootPath",request.getContextPath());

// Read the user account parameters from the login page
String sUser= getInputParameter("user",request);
String sPwd = getInputParameter("password",request);

String sForwardPage= getInputParameter("errorpage",request);
if ( sForwardPage.length()==0 ) { sForwardPage="/index.jsp?user="+encodeURL(sUser); }

if ( sUser.trim().length()>0 )
try {

// Try to open the framework with the input userName and Password
Framework framework = new Framework( sUser , sPwd );
framework.setRenderingEngine("HTML");
framework.link();
// Save the framework into the session
Application.setFramework(session,framework);
// Load the application parameters from the main menu features
loadApplicationParameters(session);
// Set session attributes for dictionary menu and common sections
session.setAttribute("MenuSection",getAppParam("dictionary_menu_section"));
session.setAttribute("CommonSection",getAppParam("dictionary_common_section"));
// Set the language based on the browser language if "use_browser_language option" is enabled
if ( use_browser_language || framework.getLanguage().length()==0 ) {

framework.setLanguage( translateBrowserLanguageToOberonLanguage(
getBrowserLanguage(request) ) );

}
// Create the application menu for the framework user (will be stored into session attribute "Menu")
createMenu( application_main_menu , session );
sForwardPage = "home.jsp";

} catch (Exception e) {

/*... do something when the user and/or password are not valid ....
go forward to the error page */
setErrorMessage(session,"Login for user '"+sUser+"' FAILED" );
session.removeAttribute(Arg.Framework);

}

%>
<jsp:forward page ="<%= sForwardPage %>"/>

menu.jsp

This JSP page is an include page (the header page); it shows the navigation menu extracted from the session attribute.

<%@include file ="library.jsp"%>
<%

// Read the input parameters
String sTitle= getInputParameter("title",request);
String sPageTitle = getInputParameter("pagetitle",request);
if ( sPageTitle.length()==0 ) { sPageTitle=sTitle; }
boolean bPopUp=getInputParameter("popup",request).equals("true");
boolean bHideBar=getInputParameter("hidebar",request).equals("true");

Framework framework = Application.getFramework(session);
String sUserName = framework.getUserName();

%>
<HTML>
<head>

</head>
<body topmargin="0" marginwidth="0" marginheight="0">
<% if (!bPopUp) { %>

<% } %>
<% if (!bHideBar) { %>

<!-- Print the navigation menu on the html page ->
<div id="menu">

<ul id="nav" >
<%= session.getAttribute("Menu") %>
</ul>

<ul class="select">
<%= createObjectMenu(session) %>
</ul>

</div>

<% } %>

<% } else { %>
<!--.... Show Title / SubTitle only ->
<% }
// Show error messages if any
String sMessage = getErrorMessage(session);
if ( sMessage.length()>0 ) { %>

<% } %>
</body>

edit.jsp

The following JSP page can perform both the object creation and the object data update (if the input ID is passed as input parameter). It also manages both the user interface for data input (createHTMLForm) and the database update process (saveFormData). These two methods are defined into the "forms.jsp" include page. The forms.jsp page represents the HTML implementation for the form administrative objects: in other words it generates the HTML code based on the form parameters and on the form-item parameters, included all the AJAX calls needed to load/refresh the field ranges and to validate the field-item values.

<%@include file ="library.jsp"%>
<%

// Get the object id as input parameter
String sID = request.getParameter("id");
boolean bCreateNew;
boolean bClone = false;
ObjectObj object;
Framework framework = Application.getFramework(session);
if ( sID==null || sID.length()==0 || getInputParameter("create",request).equals("true")) {

// Create a new object
bCreateNew=true;
object = new ObjectObj();
// Remove the "Object" from session to hide the object contextual menu
session.removeAttribute("Object");

} else {

// Open the object and read its properties
bCreateNew=false;
sID=sID.trim();
if ( getInputParameter("clone",request).equals("true") ) { bClone=true; }
object = ObjectObj.open(sID,framework);
// Add the "Object" to session to show the object contextual menu
session.setAttribute("Object",object);

}

// Get the create/edit Form name as input parameter
String sFormName = getInputParameter("form",request);
if ( sFormName.length()==0 ) {

// When the form is not passed as input parameter try to get it from the object class
Class objclass = Class.open(object.getClassName(),framework,null);
sFormName=objclass.getDefaultForm(true);

}
Form form = Form.open(sFormName,framework,null);

// Save the object data or create it
String sForwardPage = saveFormData( bCreateNew?"edit.jsp":"" , object , form ,

convertRequest(request));

if ( sForwardPage.length()>0 ) {

// A new object is succesfully created - go forward to the object detail page
%>
<script language=javascript>document.location.href="<%= sForwardPage %>";</script>
<%
return;

}

// Define title and subtitle for the menu bar
String sTitle = Dictionary.getKey(dictSection,sFormName+(bClone?"_clone":""),framework);
String sSubTitle = "";
if ( sID!=null && sID.length()>0 ) {

if (bCreateNew) {

// Clone an existing object
object =ObjectObj.open(sID,framework);
object.resetID();

}
sSubTitle=sTitle;
sTitle= getClassNameRevision(object,session);
String commonSection = getAppParam("dictionary_common_section");

}
%>
<jsp:include page ="menu.jsp" flush="true">

<jsp:param name="title" value="<%= sTitle %>" />
<jsp:param name="subtitle" value="<%= sSubTitle %>" />
<jsp:param name="popup" value="<%= (request.getParameter("popup")!=null?"true":"false")%>" />

</jsp:include>
<%@include file ="forms.jsp" %>
<!-- Print the html form with object field values->
<BODY>

<% if ( sID!=null ) { %>

function cloneObject(form) {
document.location.href="edit.jsp?id=<%= encodeURL(sID) %>&clone=true&form="+form;
}
function deleteObject(fwd) {
doObjectDestroy('<%= encodeURL(sID)%>',"<%= Dictionary.getKey (commonSection , "RemoveObjectMessage" , framework) %>",fwd);
}

</script>

<% } %>
</BODY>
</HTML>

search.jsp

The search.jsp is similar to the edit.jsp: it manages the user interface for the query input filters (createHTMLSearchForm); this method is also defined into the "forms.jsp" include page. It requires the search form name as input value and shows the HTML code based on this form parameters and on its item parameters.

<%@include file ="library.jsp"%>
<%

// Get the search Form name as input parameter
String sFormName = getInputParameter("form" ,request);
if ( sFormName.length()==0) {

out.println("NO INPUT FORM");
return;

}
Framework framework = Application.getFramework(session);
Form form = Form.open(sFormName,framework,null);

session.removeAttribute("view");
session.removeAttribute("sequence");
session.removeAttribute("Object");

// Define title and subtitle for the menu bar
String sTitle =Dictionary.getKey(dictSection,sFormName,framework);
String sSubTitle = "";
%>
<jsp:include page ="menu.jsp" flush="true">

<jsp:param name="title" value="<%= sTitle %>" />
<jsp:param name="subtitle" value="<%= sSubTitle %>" />

</jsp:include>
<%@include file ="forms.jsp" %>
<!-- Print the html search form ->
<BODY>

</BODY>
</HTML>

search_results.jsp

This JSP page executes the search query based on the filters defined into the search.jsp. It employs the searchObjects method included into the "forms.jsp" page. In addition, you can apply a view (applyView) to the query results to extract and show several object properties.

<%@include file ="library.jsp"%>
<%

// Get the search Form name as input parameter
String sFormName = getInputParameter("form" ,request);
if ( sFormName.length()==0) {

out.println("NO INPUT FORM");
return;

}
Framework framework = Application.getFramework(session);
Form form = Form.open(sFormName,framework,null);
String formHTMLName=getFormHTMLName(form);

// Execute the search query
try {
%><script language=javascript><%

clearSearchResults( formHTMLName , session );
out.println( searchObjects( form , convertRequest(request) ) );

%></script><%
} catch (Exception e) {

out.println("<font color=red>"+e.getMessage()+"</font>");

}

// Get user views
Vector vViews = listUserViews(framework);

// Apply a view to search results
String sView = getInputParameter( "view" ,request);
View view ;
if (!sView.equals("") && vViews.indexOf(sView)>=0) {

view = applyView(sView , formHTMLName , session);

}

// Define title and subtitle for the menu bar
String sTitle = Dictionary.getKey(dictSection,sFormName,framework);
%>
<jsp:include page ="menu.jsp" flush="true">

<jsp:param name="title" value="<%= sTitle %>" />

</jsp:include>
<%@include file ="forms.jsp" %>
<!-- Print the result objects ->
<BODY>
<table>

// Show the result object properties; this is a simple output, you can apply a more complex formatter
Vector vResults = getSearchResults( formHTMLName , session );
for (int i=0;i<vResults.size();i++) { %>

<tr><td><%= vResults.elementAt(i) %></td></tr><%

} %>

</table>
</BODY>
</HTML>

fileget.jsp

This JSP page shows how to download from OBEROn the attached files for a specific object instance. It extracts the file properties and displays on a html table their download links. The download process is performed with the JRFileGetServlet.

<jsp:include page ="menu.jsp" flush="true"/>
<BODY>
<table>
<%

// Get the object ID as input parameter
String sID = request.getParameter("id").trim();

Framework framework = Application.getFramework(session);
// Retrieve the object attached file properties
ObjectObj object = ObjectObj.open(sID,false,framework);
Vector vFiles = object.getFiles(framework);
// Print the list of file download links
for (int i=0;i<vFiles.size();i++) {

ObjectFile fFile = (ObjectFile) vFiles.elementAt(i); %>

<tr>

<td><a href="javascript:fileGet('<%= fFile.getFileType() %>','<%= fFile.getName() %>')">
<%= fFile.getName() %></a></td>
<td><%= fFile.getFileSize() %> bytes</td>
<td><% if (fFile.getLocker().length()>0) { out.print("Locked by"+fFile.getLocker());} %></td>

</tr><%

}

%>
</table>
<!-- Call the fileget servlet to download the file from OBEROn ->
<script language=javascript>

function fileGet(filetype,filename) {

window.open("servlet/JRFileGetServlet?id=<%= encodeURL(sID) %>

&filetype="+filetype+"&filename="+filename);

}

</script>
</BODY>
</HTML>

JRFileGetServlet input parameters

id	object id
filetype	the attached file type
filename	the file name
lock	"true" = lock the object

fileput.jsp

This JSP page shows how to upload a file to OBEROn and attach it to a specific object instance. The file is sent to the JRFilePutServlet togheter with other parameters as a "multipart/form-data" request format.

<jsp:include page ="menu.jsp" flush="true"/>
<BODY>
<%

// Get the object ID as input parameter
String sID = request.getParameter("id").trim();
String sForwardPage = "fileget.jsp?id=" + encodeURL(sID);
Framework framework = Application.getFramework(session);

%>
<!-- Call the fileput servlet in post mode to upload the file to OBEROn ->
<FORM action="servlet/JRFilePutServlet" name=putForm method=post enctype="multipart/form-data" >

<tr>

</tr>

<tr>

</tr>

<tr>

</td>

</tr>

<tr>

</td>

</tr>

</table>

</FORM>
</BODY>
</HTML>

JRFilePutServlet input parameters

id	object id
fileput	the multipart request attached file data
filetype	the file type
filename	the file name to set
unlock	"true" = unlock the object
overwrite	"true" if you want remove all files stored for the same filetype
forward	the JSP forward page

lifecycle.jsp

This JSP page loads the object's lifecycle and generate its graphical representation. The user will be able to progress or regress the status and to validate/refuse the path validations.

navigate.jsp

Shows the object's navigation tree: links can be filtered selecting the linktype and the direction.

spacetree.jsp

Visualizes the object's links by a spacial tree representation.

testgraph.jsp

This is a simple example that show how to generate charts using the OBEROn internal chart engine. The JRDrawGraphServlet is invoked passing to it the name of graph administrative object representing the chart style and the xml data representing the plot values. The servlet can also be called by a AJAX request.

<jsp:include page ="menu.jsp" flush="true"/>
<BODY>
<%

String sGraphName = request.getParameter("graph").trim();
Framework framework = Application.getFramework(session);

// Define the chart series values
GraphValues graphicValues = new GraphValues();
graphicValues.addDataLabel(graphicValues.new DataLabel("January",0,true));
graphicValues.addDataLabel(graphicValues.new DataLabel("February",0,true));
graphicValues.addDataLabel(graphicValues.new DataLabel("March",0,true));
graphicValues.addDataLabel(graphicValues.new DataLabel("April",0,true));
double[] series1 = { 4.49 , 3.47 , 1.50 , 1.71 };
graphicValues.addSeriesValues(series1);
double[] series2 = { 2.82 , 2.60 , 8.31 , 4.02 };
graphicValues.addSeriesValues(series2);
double[] series3 = { 3.49 , 4.52 , 7.94 , 9.06 };
graphicValues.addSeriesValues(series3);

%>
<iframe name="drawFrame" scrolling="yes" width="500" height="400"></iframe>
<!-- Call the drawgraph servlet in post mode to generate the chart image ->
<FORM action="servlet/JRDrawGraphServlet" name="chartForm" method=post target="drawFrame">

</FORM>
</BODY>
</HTML>

JRDrawGraphServlet input parameters

graph	the graph administrative object name
xmldata	the xml text containing the chart series values

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