Java Magazine, Jan/Feb 2016

ORACLE COM JAVAMAGAZINE JANUARY FEBRUARY 2016 25 web apps For OmniFaces SNAPSHOTS the numbering pattern is major_ version minor_ version SNAPSHOT dependency groupId org omnifaces groupId artifactId omnifaces artifactId version 23 SNAPSHOT version dependency Note Users of outdated environments who cant or wont use CDI should use OmniFaces version 111 instead It doesnt contain anything from CDI so while it works it doesnt ofer OmniFaces full range of solutions The OmniFaces artifacts are available in the following XML namespaces xmlns o http omnifaces org ui xmlns of http omnifaces org functions Using OmniFaces Probably the best way to demonstrate OmniFaces artifacts is to explore several examples For the rest of this article Ill solve common problems of JSF applications by using OmniFaces Additional examples can be found here Combine script and stylesheet resources to improve page loading As a JSF developer you should be familiar with the mechanism of loading resources in JSF Basically for each resource JSF will fire a separate GET request This is a time consuming task especially if there is a large number of resources to load The OmniFaces CombinedResourceHandler considerably improves page loading This is TAG HANDLERS converter PROVIDES SUPPORT FOR DEFERRED VALUE EXPRESSIONS IN ALL CONVERTER ATTRIBUTES RestorableView RE CREATES THE ENTIRE VIEW WHENEVER THE VIEW HAS BEEN EXPIRED importConstants MAPS CONSTANTS OF THE GIVEN FQN OF A TYPE IN THE REQUEST SCOPE importFunctions MAPS FUNCTIONS OF THE GIVEN FQN OF A TYPE IN THE FACELET SCOPE validator PROVIDES SUPPORT FOR DEFERRED VALUE EXPRESSIONS IN ALL VALIDATOR ATTRIBUTES viewParamValidationFailed HANDLES VIEW PARAMETER VALIDATION FAILURE VIA REDIRECT OR HTTP ERROR CODE CONVERTERS THESE ADVANCED CONVERTERS CLOSE GAPS IN JSF ListIndexConverter PERFORMS CONVERSION BASED ON THE POSITION INDEX OF THE SELECTED ITEM IN THE LIST ListConverter WORKS DIRECTLY VIA A List OF ENTITIES CANNOT USE ListIndexConverter SelectItemsConverter AUTOMATICALLY CONVERTS f selectItems ENTITIES SelectItemsIndexConverter SAME AS SelectItemsConverter BUT DOES CONVERSION BASED ON THE POSITION INDEX ValueChangeConverter DOES CONVERSION ONLY WHEN THE SUBMITTED VALUE HAS CHANGED GenericEnumConverter USED IN UISelectMany COMPONENTS WHOSE VALUE HAS BEEN BOUND TO A List E PROPERTY WHERE E IS AN ENUM RESOURCE HANDLERS HANDLING CDNS MULTIPLE RESOURCES IN A SINGLE CALL AND SO ON CDNResourceHandler PROVIDES CDN URLS INSTEAD OF THE DEFAULT LOCAL URLS FOR JSF RESOURCES CombinedResourceHandler CREATES A COMBINED RESOURCE FOR ALL SCRIPTS AND ONE FOR ALL STYLESHEETS UnmappedResourceHandler MAPS JSF RESOURCES ON A URL PATTERN OF javax faces resource EVENT LISTENERS InvokeActionEventListener WORKS WITH NEW f event TYPES preInvokeAction AND postInvokeAction ResetInputAjaxActionListener RESETS INPUT FIELDS THAT ARE NOT EXECUTED DURING AN AJAX SUBMIT BUT WHICH ARE RENDERED UPDATED DURING AN AJAX RESPONSE VIEW HANDLERS A USEFUL AND CORRECT USE CASE FOR VIEW HANDLERS NoAutoGeneratedIdViewHandler DOESNT ALLOW AUTO GENERATED IDS j_ id AND SO ON Table 1 List of principal components and handlers in OmniFaces continued from previous page