Eureka moment
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The document provides an overview of JavaServer Faces (JSF) concepts that are important for understanding how XPages applications work under the hood. It discusses how XPages applications run on the Java virtual machine in Domino and are processed by the server. Key points covered include the JSF lifecycle, memory management and persistence options, and how the location of code impacts performance. The document aims to help developers gain a more thorough understanding of JSF to fear less when working with XPages.
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Eureka moment
- 1. The Eureka Moment: The JSF Knowledge You Need To Understand XPages Paul Withers – Intec Systems Ltd
- 2. Agenda Introduction XPages Server Processing JVM and the NSF Memory Management JSF Event Model Summary
- 3. About Me Senior Domino Developer, Intec Systems Ltd XPages Developer since 8.5.0 IBM Champion Co-Host of The XCast
- 4. Why This Session? Nothing in life is to be feared, it is only to be understood. Now is the time to understand more, so that we may fear less. Marie Curie A matter that becomes clear ceases to concern us. Friedrich Nietzsche Furious activity is no substitute for understanding. H.H. Williams No. I am your father. Darth Vader
- 5. Expectations You should: Know what XPages are Know that XPages runs on a Domino Server Know the Computed Field, Edit Box, Repeat controls You don't: Have a thorough understanding of JSF Have expert knowledge of dataContexts, managed beans, PhaseListeners and VariableResolvers
- 6. Agenda Introduction XPages Server Processing JVM and the NSF Memory Management JSF Event Model Summary
- 7. Server Architecture Java Virtual Machine XSP Command Manager Domino HTTP Server
- 8. So When an XPage Is Served... Can HTTP Server resolve the URL? HTTP 404 Error Does user have access to NSF? HTTP Authentication Page Can HTTP Server find resource in the NSF? HTTP 404 Error
- 9. So When an XPage Is Served... Does the signer have access to run XPages? HTTP 403 Error Are there SSJS errors? XSP Command Manager takes over HTTP 500 error Return XPage
- 10. XPiNC Server-based NSFs need a local XSP Command Manager etc. XPages Extensions, Java packages must be deployed locally Authentication via Notes logon on local PC Signer access granted via ECL on local PC Logging accessible from Help → Support → View Log on local PC
- 11. Agenda Introduction XPages Server Processing JVM and the NSF Memory Management JSF Event Model Summary
- 12. Java Virtual Machine Means... Each NSF is a separate Java application sessionScope is per NSF Browser session, NOT user session Setting sessionScope in Db1.nsf does NOT set sessionScope in Db2.nsf sessionScope is ONLY within JVM – not cleared by HTTP logout
- 13. JAVA Virtual Machine XPages → Java classes → Java bytecode Each control is a Java class Extensions are pre-packaged Java classes Define properties (what can be customised) Define renderers (what is printed) SSJS code is String passed to Java method Java code prints HTML to browser
- 14. XPages Control Languages Literal values Strings, booleans etc Expression Language #{document1.FirstName} SSJS #{javascript:document1.getItemValueString(“FirstName”)} Custom All of the above
- 15. DEMO
- 16. Performance of Languages The fewer controls the better = less Java code to be run Reason for Extension Library controls Combines multiple controls into one Java class Combining languages is good EL is quicker than SSJS
- 17. Agenda Introduction XPages Server Processing JVM and the NSF Memory Management JSF Event Model Summary
- 18. JSF and Serialization HTTP is state-less JSF keeps state-full server representation of UI (component tree or view) Objects stored in component tree must be serializable (persist between requests) Domino objects recycled after each request Datasources are recycle-safe
- 20. Persistence options Component tree (map of XPage on server) either held in memory of JVM or serialized to disk xsp.persistence.XXX properties See persistence tab of new xsp.properties editor Package Explorer → WebContentWEB- INFxsp.properties
- 21. Persistence
- 22. Demo
- 23. Agenda Introduction XPages Server Processing JVM and the NSF Memory Management JSF Event Model Summary
- 24. JSF LifeCycle
- 25. Six Phases Restore View JSF component tree retrieved Apply Request Values this.setSubmittedValue(passedValue) run Any event logic run if immediate=“true” Process Validation Any converters applied Any validators applied
- 26. Six Phases Continued Update Model Values this.setValue(this.getSubmittedValue()); this.setSubmittedValue(null) Invoke Application Any event logic run Render Response HTML rendered and state saved Only event that runs during page load
- 27. AbstractPhaseListener Abstract because it can't be instantiated Implements javax.faces.event.PhaseListener Allows us to track JSF lifecycle phases Java class plus reference in faces-config
- 28. DEMO
- 29. Basic Processing Validation fails beforeRestoreView afterRestoreView beforeApplyRequestValues afterApplyRequestValues beforeProcessValidations beforeRenderResponse afterRenderResponse Event logic not run
- 30. No Validation Conversion still honoured If failed, skips from ProcessValidations to RenderResponse Event Logic not run If no conversion errors, all phases run Values passed from submittedValue to value Component tree updated
- 31. immediate=“true” Validation fails beforeRestoreView afterRestoreView beforeApplyRequestValues afterApplyRequestValues beforeRenderResponse afterRenderResponse Event logic run in ApplyRequestValues phase Component value never goes past submittedValue Component tree not updated
- 32. Performance Smackdown Compute on Page Load (Loaded) Compute Dynamically (Runtime) Theme dataContexts “Global variables” Scoped to XPage, Custom Control, Panel Referenced via EL – #{var1}
- 33. Performance Smackdown Page Load – how many calls Partial Refresh – how many calls execMode=“partial” Runs over only part of component tree
- 34. DEMO
- 35. Smackdown Results Loaded makes fewer calls Theme cannot override loaded Runtime and theme makes same calls dataContext makes fewer calls execMode=“partial” improves performance IMPORTANT: Define id to execute lifecycle on EventHandler – All Properties
- 36. Bonus – Repeats Revisited See Bonus – Java Performance + Rendered rendered property set for each of 50000 rows SSJS in Script Library performs worst SL much worse on partial refresh VariableResolver best for performance Deprecated in JSF 2.0 for ELResolver DataContext next best (rendered property), but only reusable within page
- 37. Summary Scoped variables not cleared by ?logout Combining controls improves performance Persistence options can optimise application JSF lifecycle affects event processing Loaded and dataContexts offer benefits execMode improves performance
- 38. Summary Script libraries work for application reusability dataContexts better for page reusability VariableResolver best for application-level reusability Upgrade VariableResolver to ELResolver when XPages updated to JSF 2.0 Use AbstractPhaseListener to test
- 42. To Download Sample App Source code at http://projects.qtzar.com/projects/jsf_eureka Source control with Git Download and install eGit from OpenNTF Create new project from source code Associate with new NSF
- 43. Thank You, Questions & Evals Paul Withers, Intec Systems Ltd Email: pwithers@intec.co.uk Twitter: paulswithers Blog: www.intec.co.uk/blog Please complete evaluations
Notas do Editor
- Human nature is to resist what is new because we don't understand it. Lots of new things going on behind scenes in XPages. This session will demystify some. Who has struggled with a problem for hours, then found one piece of information that would have given you the answer straight away, if you'd known it? That's the Eureka moment: one crucial piece of info that explains everything.
- If you attended Intro to XPages session, you will be able to keep up with this session. If you didn't go because you knew it, you'll be able to keep up with this session. If you know what a VariableResolver is, how to code one, why you might need to change it in the future, go get a beer!
- Traditional Domino web apps used HTTP server. Java servlets used JVM XPages uses both How? When?
- HTTP 500 if fatal error with XPages runtime - memory issue - Extension Library used by app but not installed - Java class cannot be loaded (NoClassDefFoundError) - Other database compile issue
- XPINC IS LOCAL EVEN IF NSF IS ON SERVER
- Who wants a demo? NOTE SPECIFICALLY sessionScope.sessionID
- Summary of demo
- Jump to Application Perspective – Package Explorer – Project Explorer Java code does the same as an Xagent - facesContext,getResponseWriter() - writer.write()
- Based on previous slides, what will happen? If we split languages across controls, so controls with single language? If we combine literal values and A.N.Other language? If we use different languages?
- Summary of demo
- If you want to store / pass info between requests - Add to QueryString - Store in cookies - Pass in AJAX request in response JSF handles this – we've seen sessionID cookie and JSF sessionID in sessionScope. This ensures same session is used Recycle-safe, i.e. values are stored in Java beans and written back to the server as and when required. We'll come back tot hat later.
- If you want to store / pass info between requests - Add to QueryString - Store in cookies - Pass in AJAX request in response JSF handles this – we've seen sessionID cookie and JSF sessionID in sessionScope. This ensures same session is used Recycle-safe, i.e. values are stored in Java beans and written back to the server as and when required. We'll come back tot hat later.
- Screenshots of new Persistence tab of xsp.properties file Server Page Persistence – see demo Page Persistence Mode
- If immediate = “true” and using component values, need to use getComponent(“myComponent”).getSubmittedValue()
- If NOT using immediate = “true” and using component values, need to use getComponent(“myComponent”).getValue()
- In the following demos, I'm using an AbstractPhaseListener to check what's happening where
- Let's see what happens during page events
- Summary of results of JSF Lifecycle - Basic
- Summary of results of JSF Lifecycle – No Validation
- Summary of results of JSF Lifecycle - Immediate
- Let's see what happens depending on where Computed Field value property and Edit Box rendered property are defined
- Summary of demo