18 Invaluable Lessons About ADF Faces Page LifecycleSteven Davelaar twitter:@stevendavelaarblogs: www.ateam-oracle.com and blogs.oracle.com/jheadstartOracle Fusion Middleware Architects Team (the A-team)Agenda Worlss most comprehensive Hello World DemoJust Say Hello JSF Lifecycle Initial1. Restore ViewUI Component TreeRichPanelHeaderRichPanelGroupLayout6. Render ResponseRichPanelGroupLayoutRichPanelFormLayoutRichInputTextRichInputDateJSF Lifecycle - Postback1.Restore View2. Apply Request ValuesrichInputText.setSubmittedValue(Steven)richInputDate.setSubmittedValue(04-12-2012)JSF Lifecycle - Postback1.Restore View2. Apply Request Values3. Process Validations Validate and convert (if needed) name and date Call richInputText.setValue() with converted value if valid Clear submittedValue Queue valueChange event (if applicable)1.Restore View2. Apply Request Values3. Process Validationsvalue=#{viewScope.HelloBean.name}value=#{viewScope.HelloBean.date}JSF Lifecycle Postback4. Update Model Call HelloBean.setName with component value Call HelloBean.setDate with component value Clear submitted and (local) component valueJSF Lifecycle Postback1.Restore View2. Apply Request Values3. Process ValidationsactionListener=#{viewScope.helloBean.sayHello}4. Update Model Call HelloBean.sayHello5. Invoke ApplicationJSF Lifecycle - Postback1.Restore View2. Apply Request Values3. Process Validations4. Update Model5. Invoke Application6. Render ResponseCurrent Lifecycle Phase in JDeveloperwhile DebuggingJust Say Hello Reset Values Clicking the Reset button should not fire validation, and should clear the Name and Date fields We need a lifecycle shortcut that bypasses validation (both client-side and server-side) and model updateJSF Lifecycle Postback Immediate Lesson 1: An immediate command executes the action and actionListener in phase 2. Apply Request Values and then jumps to phase 6. Render Response, skipping validation and model update phases.JSF Lifecycle Postback Immediate1.Restore View2. Apply Request Values richInputText.setSubmittedValue(Steven) richInputDate.setSubmittedValue(04-12-2012) Call HelloBean.resetJSF Lifecycle Postback Immediate1.Restore View2. Apply Request Values6. Render Response We clicked the Reset button. Name and date are cleared in HelloBean. But we still see the old values in the page! How come??JSF Lifecycle Postback Immediate Lesson 2: When executing an immediate command, the UI components do NOT re-evaluate their underlying value binding, possibly showing stale data How to force the UI components to do this? Three options Use af:resetActionListener Use oracle.adf.view.rich.util.ResetUtils.reset() UIComponent.resetValue() On an individual UI component, the reset action Clears the submittedValue Clears local component value so value binding is re-evaluated Marks the component as validUsing af:resetActionListener Easiest option, no Java method needed Automatically added when dragging and dropping a Rollback operation from Data Control Palette Lesson 3: af:resetActionListener does NOT reset child regions, use ResetUtils.reset() instead.Using ResetUtils.reset(UIComponentstartComponent) Reset method takes one parameter: the start UI Component to reset However, this is not the REAL start component Is used to traverse up the component tree until a region, form, subform, popup, carrousel or panelCollection is found that component is used as the real starting point Agenda Worlss most comprehensive Hello World DemoSay Hello Suggestions Suggest the type of greeting based on a persons nameSay Hello Suggestions Will this work?Not really..Say Hello Suggestions Will immediate=true work? No, model is no longer updated, getName() will return null (or old model value): remember lesson 1! AND (wrong) greeting will NOT be displayed anyway: remember lesson 2!Say Hello Suggestions Challenges We need immediate=true to prevent premature validation of greeting field and date field We need to refresh the greeting field properly We need somehow to get hold of value entered in name field name field We do want required validation on name field----------------------------------------------------------------------- We already learned how to refresh the greeting field with underlying model value..we need to call resetValue on the greeting inputTextSay Hello Suggestions Use Binding Property to Refresh Greeting FieldSay Hello Suggestions Greeting Field Refreshed At least the suggested greeting is displayed now, although it is still the wrong default greeting because getName() returns null in the suggest methodSide Step More About Component Binding The getter/setter methods generated by JDeveloperwhen using binding property are wrong Code is not serializable, causing errors in clustered env. UI Tree not released properly, more memory usage UI component might be reused in UI Tree of another page (fragment) (fragment) This can happen EVEN with request-scoped and backingBean-scoped beans Lesson 4: Always use ComponentReference in component binding getter/setter methods Lesson 5: Never use component binding in session-scoped bean, even ComponentReference wont be safe then.Side Step Correct Code for Component Binding MethodsSide Step More About Component Binding Component binding is often overly used Use UIManager pattern from Duncan Mills to avoid unnecessary component binding https://blogs.oracle.com/groundside/entry/the_uimanager_pattern You can also find a component by id programmatically using invokeOnComponent API See (google for) ADF Code Corner sample 58 Starting UI component should be as low as possible in UI Tree, starting at UIViewRoot can kill performance with large, multi-tab pages Say Hello Suggestions Challenges We need immediate=true to prevent premature validation of greeting field and date field We need to refresh the greeting field properly We need somehow to get hold of value entered in name field name field We do want required validation on name field ----------------------------------------------------------------------- May be we can use a valueChangeListener on name field? May be we can use immediate=true on the name field?Say Hello Suggestions Using a ValueChangeListener ValueChangeListener fires in phase 3. Process Validations That phase is skipped with immediate command Now, lets set immediate=true on name field Say Hello Suggestions Using a ValueChangeListener Lesson 6: When immediate=true on an Editable UI ComponentComponent Component validation is processed in phase 2. Apply Request Values The validated and converted value is stored on the component valueChangeListener is also called in this phase YES, now it works! But wait .Say Hello Suggestions Using immediate on editable component If we enter all fields except name, then Reset button no longer works! Why? Because of Lesson 6: name field now validated in Apply request Values, before reset command is executed. Arrrrggghhh! executed. Arrrrggghhh!Say Hello Suggestions Using Immediate on Editable Component This makes setting immediate=true on an editable UI component pretty useless, because then the general rule Validations are skipped when setting a command component to immediate=true component to immediate=trueis no longer true! Lesson 7: Never set immediate=true on an editable UI component, it prevents you from cancelling/abandoning a page.Say Hello Suggestions Back to the Challenges We need immediate=true to prevent premature validation of greeting field and date field We need to refresh the greeting field properly We need somehow to get hold of value entered in name fieldname field We do want required validation on name field----------------------------------------------------------------------- Not a solution: valueChangeListener and immediate=true on name field New solution: we need to get the value entered for name directly from the UI component Say Hello Suggestions Use Component Binding to Get Name Value YES, this works, and the reset button still works too! But wait. it works too well Method should not execute when name empty, or less than 4 charsSay Hello Suggestions Use Component Binding to Get Name Value We are using the raw, possibly invalid value by calling getSubmittedValue() on the name field We need to do programmatically what normally happens automatically in phase 33. Process Validationsin phase 3 Validate and convert (if needed) name and date Call richInputText.setValue() with converted value if valid Clear submittedValue Queue valueChange event (if applicable)Say Hello Suggestions Use Component Binding to Get Name Value Lesson 8: You can programmatically execute JSF lifecycle phases 3 and 4 on a component: comp.processValidations(FacesContext.getCurrentInstance()) comp.processUpdates(FacesContext.getCurrentInstance())Say Hello Suggestions Optimizing Using Partial Page Rendering (PPR) When clicking the suggest button, only the greeting field needs to be refreshed in browser. Easily implemented using ADF Faces PPR Agenda Worlss most comprehensive Hello World DemoSub Forms of Hello Saying It was quite a challenge to get this greeting suggestion implemented Is there really no easier way to do this? The af:subform tag represents an independently submittable region of a page. The contents of asubmittable region of a page. The contents of a subform will only be validated (or otherwise processed) if a component inside of the subform is responsible for submitting the page. Sounds promising, lets try!Sub Forms of Hello Saying Try 1Sub Forms of Hello Saying Try 1Sub Forms of Hello Saying Try 1 Findings Lesson 9: Items not in any sub-form are still processed in lifecycle when submitting a sub-form. Fix: put all items in sub-forms Lesson 10: Layout messed up when using sub form Fix: Each subform must contain its own panelFormLayout, Fix: Each subform must contain its own panelFormLayout, align accross panelFormLayouts using labelWidth property Submitting the main form, does not submit items in sub-form Solution: set property default=true on the subformSub Forms of Hello Saying Try 2Sub Forms of Hello Saying Try 2 Findings Suggest button now works with empty date! Layout cleaned up! Pressing enter key on name shows suggested greeting! But wait. what is functionally different from previous samples? Greeting field is not required, what if we fix that?Sub Forms of Hello Saying Try 2 Findings Lets try to move greeting field to other subformSub Forms of Hello Saying Try 3Sub Forms of Hello Saying Try 3 Findings No validation error on greeting field! But greeting no longer shown Lesson 11: Partial page refresh does not work across sub-forms Sub forms do not work for this use case Sub Forms of Say Hello - Conclusion Sub forms can be used in corner cases to avoid premature validation Sub forms most useful for default command behaviorAgenda Worlss most comprehensive Hello World DemoAuto-Suggested Hello Saying Auto-suggest the type of greeting when tabbing out the name fieldAuto-Suggested Hello Saying Will this work? Will field validations fire prematurely? Will greeting field be refreshed correctly?Auto-Suggested Hello Saying ADF-optimized lifecycle Using autoSubmit = true on an editable UI Component kicks of the ADF-Optimized JSF Lifecycle This optimized lifecycle always: fires a partial submit By default will only process and refresh the autoSubmitted By default will only process and refresh the autoSubmittedcomponent itself Additional UI componentswill be processed in this lifecycle when partialTriggers property points to autoSubmitted item So, with code in previous slide no premature validations fire but greeting field is not refreshed So, what will happen when we add partialTriggerproperty to greeting field?Auto-Suggested Hello Saying Refreshing Greeting Field Greeting field now processed as well -> validation error when null Solutions: 1. make greeting optional2. add greeting programmatically as partial targetAuto-Suggested Hello Saying Making Greeting Optional Making greeting optional seems to work But it doesnt work always It does not work when user clears greeting first User clears existing greeting User navigates back to name field and changes the name User navigates back to name field and changes the name User tabs out name field, nothing happens! Why??What happens when greeting is cleared1.Restore View2. Apply Request Values3. Process Validations Calls valueChangeListener method HelloBean.nameChanged which in turn calls.setGreeting(Hi)1.Restore View2. Apply Request Values3. Process ValidationsWhat happens when greeting is cleared4. Update Model Calls HelloBean.setGreeting(null) Overrides the value set by valueChangeListenermethod .How to prevent suggested greeting is overridden again The JSF Model Update phase only updates underlying model value when the local component value differs from the model value We need to reset the local UI Component value in namedChanged method namedChanged methodAuto-Suggested Hello Saying Refreshing Greeting Field In CodeAuto-Suggested Hello Saying Lessons Learned12. Auto-submitted fields use ADF optimized lifecycle preventing premature validation on other fields13. The components that are processed by ADF optimized lifecycle can be configured using partialTriggerproperty. This is known as Cross Component Refresh property. This is known as Cross Component Refresh14. Values set in value change listeners might be overridden in model update phase if not coded correctly15. Use programmatic PPR instead of partialTriggersproperty to prevent components to be processed by ADF optimized lifecycle, avoiding premature validationNew in JDeveloper 12c: the af:targettag! Provides a declarative way to allow a component to specify the list of targets it wants executed and rendered when an event is fired by the component. The list of components on which the JSF lifecycle will be executed, can be defined separately from the listbe executed, can be defined separately from the list of components that needs to be re-rendered (refreshed). Lets revisit our previous examples.JSF Lifecycle Postback Immediate1.Restore View2. Apply Request Values6. Render Response We clicked the Reset button. Name and date are cleared in HelloBean. But we still see the old values in the page! How come??JSF Lifecycle Postback Immediate Lesson 2: When executing an immediate command, the UI components do NOT re-evaluate their underlying value binding, possibly showing stale data How to force the UI components to do this? Three options Use af:resetActionListener Use oracle.adf.view.rich.util.ResetUtils.reset() UIComponent.resetValue() On an individual UI component, the reset action Clears the submittedValue Clears local component value so value binding is re-evaluated Marks the component as validImplementing Reset/Cancel Functionality using af:target tag! No need to set immediate=true on the button No issues with fields not being refreshed No issues with subregions not being refreshed when using af:resetActionListenerSay Hello Suggestions Suggest the type of greeting based on a persons nameSay Hello Suggestions Challenges We need(ed) immediate=true to prevent premature validation of greeting field and date field We need to refresh the greeting field properly We need somehow to get hold of value entered in name field name field We do want required validation on name field----------------------------------------------------------------------- With af:target tag this becomes easy!Suggest Greeting Using af:target tagAuto-Suggested Hello Saying Auto-suggest the type of greeting when tabbing out the name fieldAuto-Suggest Greeting Using af:targettagThe af:target tag is your friend! Lesson 16: When using JDeveloper 12c, use the af:target tag to easily define which components should be validated and submitted, and which components should be re-rendered.Agenda A bit more on the ADF optimized lifecycleADF Optimized Lifecycle ADF Faces sets boundaries on the page that allow the JSF lifecycle to run just on components within the boundary As we learned before, when autosubmitting an editable field, the boundary is the component itself editable field, the boundary is the component itself Boundaries can be changed by using partialTriggerspropertyADF Optimized Lifecycle A number of component events always trigger the optimized lifecycle Events on table, treeTable: disclosureEvent, selectionEvent, rangeChangeEvent, columnSelectionEvent, etc Events on tree: disclosureEvent, selectionEvent Events on showDetailIHeader: disclosureEvent Events on panelAccordion (showDetailIItem) : disclosureEvent Events on components inside panelCollection (toolbar, context menu, etc) Optimized Lifecycle of Employees Overflow Right When clicking on another row Overflow area should be refreshed Changes in overflow area should be preservedOptimized Lifecycle of Employees Configuring optimized lifecycle When clicking on another row, changes in overflow area are now preservedOptimized Lifecycle of Employees Adding New Employee Clicking the New Employee button should also preserve changes made in table overflow area Easy works out-of-the-box Now, lets move that button to panelCollection toolbarOptimized Lifecycle of Employees Adding New Employee Now, it will NOT work out-of-the-box Button inside panelCollection will trigger optimized lifecycle Changes in table overflow area will not be submitted What is the obvious fix?Optimized Lifecycle of Employees Adding New Employee Obvious fix is to add button id to partialTriggersproperty of panelFormLayout Lesson 17: To add components that should be processed in optimized lifecycle, the partialTriggerproperty must point to the boundary component In this use case, the boundary component of the optimized lifecycle is the panelCollection So, obvious fix does not work, this will work: Note that you can use cascading partialTriggers If panelCollection partialTriggers property refers to table, panelFormLayout only needs to refer to panelCollectionAgenda Worlss most comprehensive Hello World DemoSay Hello with a SongSay Hello with a Song Choose Song checkbox will need autoSubmit = true Question 1:Can we use a partialTrigger property or do we need programmatic PPR to show/hide the Song drop-down list? Song selectOneChoice will need autoSubmit = true Song selectOneChoice will need autoSubmit = true Question 2:Can we use a partialTrigger property or do we need programmatic PPR to show/hide the YouTube video frame?Say Hello with a Song Choose Song checkbox will need autoSubmit = true Question 1:Can we use a partialTrigger property or do we need programmatic PPR to show/hide the Song drop-down list? Song selectOneChoice will need autoSubmit = true Song selectOneChoice will need autoSubmit = true Question 2:Can we use a partialTrigger property or do we need programmatic PPR to show/hide the YouTube video frame?Say Hello with a Song Try 1 Will this work?Say Hello with a Song Lesson 18: To show/hide a component, the parent component should be refreshed Answer 1: we need to refresh the enclosing panelFormLayout to see the song selectOneChoice Using partialTrigger would cause premature validation errors Using partialTrigger would cause premature validation errors (lesson 15), so we use programmatic PPR Answer 2: No validation issues, we can safely use partialTriggers propertySay Hello with a Song Correct CodeMore Info Understanding the JSF and ADF Optimized Lifeycle Slides and sample apps downloadable http://www.ateam-oracle.com/?p=3719 Avoiding JSF and ADF Lifecycle Frustrations Shortened recording of this presentation by Frank Nimphius Shortened recording of this presentation by Frank Nimphius http://download.oracle.com/otn_hosted_doc/jdeveloper/11gdemos/JsfADFLifecycle/adfInsiderJsfAdfLifecycle.html A Hidden Gem of ADF Faces: The af:target tag: http://www.ateam-oracle.com/?p=20570Final Recommendation Write the lessons down, print them, put them on the wall, learn them by heart, and rehearse them every week, it will save you tons of frustration!