Grokking the Paradigm Creating a Component

Grokking the ParadigmCreating a Component Dennis Dawson Principal Technical Writer EMC/Documentum

Creating a Custom Component Lay out the UI Create Java behavior classes Create configuration files Fifteen Minutes’ Worth of Stuff Grokking the Paradigm

Creating a Component • Components are composed of • The UI Layer (JSP) • Behavior (Java) • Configuration (XML) • For this example, we’ll create a simple XML editor • We’ll create a new UI, a component configuration and supporting Java class • We’ll extend the existing edit_file action configuration and extend its supporting Java class Grokking the Paradigm

No Rules!! • You can create the parts in any order • I like to start with the UI • Show it to your users for feedback before you complete the implementation • Something tangible to look at as you develop the component • Feel like you’ve accomplished something Grokking the Paradigm

Creating a ComponentThe UI Layer <%@ page contentType = "text/html" %> <%@ page errorPage = "/wdk/errorhandler.jsp" %> <%@ taglib uri = "/WEB-INF/tlds/dmform_1_0.tld" prefix="dmf" %> <dmf:html><dmf:head> <dmf:webform /> </dmf:head><dmf:body><dmf:form> <dmf:table><dmf:tr><dmf:td colspan = "2" > <dmf:textarea name = "textXmlData" rows = "30" cols = "150" /> </dmf:td></dmf:tr><dmf:tr><dmf:td> <dmf:button name = "save" label = "Save Changes" onclick = "onClickSaveChanges" /> </dmf:td><dmf:td align = "right" > <dmf:button name = "cancel" label = "Cancel Changes“ onclick = "onClickCancel" /> </dmf:td></dmf:tr></dmf:table> </dmf:form></dmf:body></dmf:html> Grokking the Paradigm

Creating a Component – The UI JSP • The UI consists of a text area for editing, a button to save changes, and a button to cancel changes. Grokking the Paradigm

Creating a Component –Java Behavior Class • LaunchXMLViewer extends LaunchComponentWithPermitCheck • Here’s the interesting chunk of code public boolean execute( String strAction,IConfigElement config, ArgumentList args, Context context, Component component, java.util.Map map) { ... if((strContentType.indexOf(m_strXMLContentType) == -1) && (strContentType.indexOf(m_strXSLContentType) == -1)) { return (super.execute( strAction, config,args,context,component,map) ); } else { component.setComponentNested( "xmlviewer",args,component.getContext(),null); } Grokking the Paradigm

Creating a Component -Configuring the Action • We need to extend dm_sysobject_actions.xml • We’ll modify the editfile action to point to our new Java class <?xml ... <action id = "editfile“ extends= "editfile:/webcomponent/config/actions/dm_sysobject_actions.xml" > ... <execution class = "com.documentum.custom.action.LaunchXMLViewer" > <permit>version_permit</permit> <component>edit</component> <container>editcontainer</container> </execution> </action> Grokking the Paradigm

Creating a Component – The Java Behavior Class • Let’s pick the XMLViewer class apart a section at a time, starting with the import statements package com.documentum.custom.library; import com.documentum.web.common.ArgumentList; import com.documentum.web.form.Control; import com.documentum.web.form.control.TextArea; import com.documentum.web.formext.component.Component; import com.documentum.fc.client.IDfSession; import com.documentum.fc.client.IDfSysObject; import com.documentum.fc.common.DfId; import com.documentum.fc.common.DfException; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; Grokking the Paradigm

Creating a Component – The Java Behavior Class • Let’s pick the behavior class apart a section at a time, starting with the import statements package com.documentum.custom.library; import com.documentum.web.common.ArgumentList; import com.documentum.web.form.Control; import com.documentum.web.form.control.TextArea; import com.documentum.web.formext.component.Component; import com.documentum.fc.client.IDfSession; import com.documentum.fc.client.IDfSysObject; import com.documentum.fc.common.DfId; import com.documentum.fc.common.DfException; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; Grokking the Paradigm

Creating a Component – The Java Behavior Class • In my examples, I put my variable definitions at the top of the file for readability, but they usually show up at the end of most Java files. public class XMLViewer extends Component { private String m_strObjectId = null; private IDfSysObject m_sysObjectXmlDoc = null; private String m_strXmlData = null; private IDfSession m_docbaseSession = null; private static final String m_strXMLContentType = "xml"; Grokking the Paradigm

Creating a Component – The Java Behavior Class • The initialization routine initializes the XML content, and, if successful, displays it in the text area public void onInit(ArgumentList args) { super.onInit(args); m_strObjectId = args.get("objectId"); if(m_strObjectId != null) { m_docbaseSession = getDfSession() if(initXMLContent()) { displayXmlData(); } } } Grokking the Paradigm

Creating a Component – The Java Behavior Class This method reads the XML content into the m_strXmlData variable: private boolean initXMLContent() {... String contentType = m_sysObjectXmlDoc.getContentType(); if( m_sysObjectXmlDoc.isCheckedOut()) { String lockOwner = m_sysObjectXmlDoc.getLockOwner(); String currentUser = getCurrentLoginUsername(); if(! currentUser.equals(lockOwner)) return false; } ByteArrayInputStream xmlData = m_sysObjectXmlDoc.getContent(); byte byteXmlData[] = new byte[xmlData.available() + 3]; xmlData.read(byteXmlData,0,xmlData.available()); m_strXmlData = new String(byteXmlData); return true; } Grokking the Paradigm

Creating a Component – The Java Behavior Class The second piece to instantiation is actually displaying the XML data private void displayXmlData() { TextArea textArea = (TextArea) getControl("textXmlData"); if(textArea == null) { textArea = (TextArea) createControl("textXmlData",TextArea.class); } textArea.setValue(m_strXmlData); } Grokking the Paradigm

Creating a Component – The Java Behavior Class public void onClickSaveChanges(Control control, ArgumentList args) { saveXmlData(); } } Grokking the Paradigm

Creating a Component – The Java Behavior Class private void saveXmlData() { if(m_sysObjectXmlDoc.isCheckedOut()) { TextArea textArea = (TextArea) getControl("textXmlData"); m_strXmlData = textArea.getValue(); ByteArrayOutputStream outputStream = new ByteArrayOutputStream(); outputStream.write(m_strXmlData.getBytes()); m_sysObjectXmlDoc.setContent(outputStream); m_sysObjectXmlDoc.checkin(false,""); setComponentReturn(); } else { setComponentReturn(); } } Grokking the Paradigm

Creating a Component – The Java Behavior Class public void onClickCancel(Control control, ArgumentList args) { try { if(m_sysObjectXmlDoc.isCheckedOut()) { m_sysObjectXmlDoc.cancelCheckout(); } } catch(DfException dfe) { dfe.printStackTrace(); } setComponentReturn(); } Grokking the Paradigm

Creating a Component – The Component Configuration File • We create a component definition in an XML configuration file. • This is the “glue” that associates the UI with the Java behavior class <?xml version="1.0" encoding="ISO-8859-1" standalone="no"?> <config version="1.0"> <scope type = "dm_document" > <component id = "xmlviewer" > <params> <param name = "objectId" required = "true" /> </params> <pages> <start>/custom/library/xmlViewer.jsp</start> </pages> <class>com.documentum.custom.library.XMLViewer</class> </component> </scope> </config> Grokking the Paradigm

Creating a Component – Deploying the Component • After creating all of these files and compiling the Java classes, you deploy the files to the following locations: /webtop/custom/library/xmlViewer.jsp /webtop/custom/config/edit_action.xml /webtop/custom/config/xmlviewer_component.xml /webtop/WEB-INF/classes/com/documentum/custom/action/ LaunchXMLViewer.class /webtop/WEB-INF/classes/com/documentum/custom/library/ XMLViewer.class Grokking the Paradigm

Multiplicitas Componatis Res Simplex • Taken as a whole, Webtop and WDK-based applications are intricate, multifaceted feats of programming • When you focus on any one element of the application, it’s easy to follow the logic and duplicate its behavior • Once you grok the paradigm, enhancing and customizing complex applications becomes a series of simple steps Grokking the Paradigm

Clarifications/comments?Please send them to:dawson_dennis@emc.comWDK Questions? Please visit:http://developer.emc.com/developer/

Grokking the Paradigm Creating a Component

Grokking the Paradigm Creating a Component

Presentation Transcript

Creating a New Business Paradigm

Grokking Software Architecture

Creating a New Business Paradigm

Grokking Software Architecture

The Immigration Paradigm

Questions? A Key Component of Innovating, Educating, and Creating

The Wilderness of a Paradigm Shift

Grokking the Paradigm: Why I Get Confused (and what I’m doing about it)

A New Paradigm

The AGN Torus: A Paradigm Change

Grokking Hash Tables

Grokking the Paradigm Modifying Menus

Grokking the Paradigm Changing Column Layouts

A New Paradigm

Grokking the Paradigm Quickie Configurations

The Paradigm as a Radial Category

Grokking the Paradigm Reconstructing Webtop

Creating a Paradigm Shift in Early Intervention:

Changing the risk paradigm – a debate

A paradigm shift:

The Reactive Paradigm