So, we have created many templates using handlebars. Out of the many, we have one handlebar where we would like to make some changes that should only go live after a certain date. To do so, we wanted to create sort of a toggle switch, something like:
{{if switch on}}
display new content
{{else}}
display old content
Below is the generic template parser where I am trying to create a switch that I can inject in the if part of my template. Any suggestions?
/**
* Creates HTML output of the specified context for the given templateId and templateVersion combination
* we implicitly assume certain json fields (template specific) to be present in the content
*/
#Timed("handlebarsService.parseTemplateToHtml")
fun parseTemplateToHtml(htmlTemplateLocation: String, model: Map<String, Any>, locale: Locale): String {
val modelWithLanguage = model.toMutableMap()
modelWithLanguage[languageTag] = locale.language
//modelWithLanguage[switch] = "off"
val context = Context.newBuilder(modelWithLanguage)
.resolver(MapValueResolver.INSTANCE)
.build()
val template = try {
handlebars.compile(htmlTemplateLocation)
} catch (e: IOException) {
throw PdfGenerationException(e, "Internal error while compiling template")
}
return try {
template.apply(context)
} catch (e: IOException) {
throw PdfGenerationException(e, "Internal error while applying template")
}
}
}
private const val languageTag = "languageTag"
//private const val switch ="off"
Related
Hey I am very new to tornadofx struggeling with async loading of data for the treeview. I am loading categories from a rest endpoint, which I want to show in there.
It seems like there's no direct data binding to the children.
when using 'bindChildren' I can provide the observable list, but I have to convert them into Node's. which then would make the populate block kind of obsolete.
What's the recommended way of doing this? I cannot find anything about this.
// Category
interface Category<T : Category<T>> {
val id: String
val name: String
val subcategories: List<T>?
}
//default category:
class DefaultCategory(override val name: String) : Category<DefaultCategory> {
override val id: String = "default"
override val subcategories: List<DefaultCategory>? = null
}
//ViewModel
class CategoryViewModel : ViewModel() {
val sourceProperty = SimpleListProperty<Category<*>>()
fun loadData() {
// load items for treeview into 'newItems'
sourceProperty.value = newItems
}
}
// TreeViewFactoryMethod
private fun createTreeView(
listProperty: SimpleListProperty<Category<*>>
): TreeView<Category<*>> {
return treeview {
root = TreeItem(DefaultCategory("Categories"))
isShowRoot = false
root.isExpanded = true
root.children.forEach { it.isExpanded = true }
cellFormat { text = it.name }
populate { parent ->
when (parent) {
root -> listProperty.value
else -> parent.value.subcategories
}
}
}
}
Assuming that on a button click I call viewmodel.loadData(), I would expect the TreeView to update as soon as there's some new data. (If I would've found a way to bind)
I've never had to use bindChildren for TornadoFX before and your use of async isn't very relevant to what I think is your primary problem. So, admittedly, this question kind of confused me at first but I'm guessing you're just wondering why the list isn't appearing in your TreeView? I've made a test example with changes to make it work.
// Category
interface Category<T : Category<T>> {
val id: String
val name: String
val subcategories: List<T>?
}
//default category:
class DefaultCategory(override val name: String) : Category<DefaultCategory> {
override val id: String = "default"
override val subcategories: List<DefaultCategory>? = null
}
//Just a dummy category
class ChildCategory(override val name: String) : Category<ChildCategory> {
override val id = name
override val subcategories: List<ChildCategory>? = null
}
//ViewModel
class CategoryViewModel : ViewModel() {
//filled with dummy data
val sourceProperty = SimpleListProperty<Category<*>>(listOf(
ChildCategory("Categorya"),
ChildCategory("Categoryb"),
ChildCategory("Categoryc"),
ChildCategory("Categoryd")
).asObservable())
fun loadData() {
sourceProperty.asyncItems {
//items grabbed somehow
listOf(
ChildCategory("Category1"),
ChildCategory("Category2"),
ChildCategory("Category3"),
ChildCategory("Category4")
).asObservable()
}
}
}
class TestView : View() {
val model: CategoryViewModel by inject()
override val root = vbox(10) {
button("Refresh Items").action {
model.loadData()
}
add(createTreeView(model.sourceProperty))
}
// TreeViewFactoryMethod
private fun createTreeView(
listProperty: SimpleListProperty<Category<*>>
): TreeView<Category<*>> {
return treeview {
root = TreeItem(DefaultCategory("Categories"))
isShowRoot = false
root.isExpanded = true
root.children.forEach { it.isExpanded = true }
cellFormat { text = it.name }
populate { parent ->
when (parent) {
root -> listProperty
else -> parent.value.subcategories
}
}
}
}
}
There are 2 important distinctions that are important.
1. The more relevant distinction is that inside the populate block, root -> listProperty is used instead of root.listProperty.value. This will make your list appear. The reason is that a SimpleListProperty is not a list, it holds a list. So, yes, passing in a plain list is perfectly valid (like how you passed in the value of the list property). But now that means the tree view isn't listening to your property, just the list you passed in. With that in mind, I would be considerate over the categories' subcategory lists are implemented as well.
2. Secondly, notice the use of asyncItems in the ViewModel. This will perform whatever task asynchronously, then set the items to list on success. You can even add fail or cancel blocks to it. I'd recommend using this, as long/intensive operations aren't supposed to be performed on the UI thread.
I'd like to make wrapper to implement simple data binding pattern -- while some data have been modified all registered handlers are got notified. I have started with this (for js target):
class Main {
public static function main() {
var target = new Some();
var binding = new Bindable(target);
binding.one = 5;
// binding.two = 0.12; // intentionally unset field
binding.three = []; // wrong type
binding.four = 'str'; // no such field in wrapped class
trace(binding.one, binding.two, binding.three, binding.four, binding.five);
// outputs: 5, null, [], str, null
trace(target.one, target.two, target.three);
// outputs: 5, null, []
}
}
class Some {
public var one:Int;
public var two:Float;
public var three:Bool;
public function new() {}
}
abstract Bindable<TClass>(TClass) {
public inline function new(source) { this = source; }
#:op(a.b) public function setField<T>(name:String, value:T) {
Reflect.setField(this, name, value);
// TODO notify handlers
return value;
}
#:op(a.b) public function getField<T>(name:String):T {
return cast Reflect.field(this, name);
}
}
So I have some frustrating issues: interface of wrapped object doesn't expose to wrapper, so there's no auto completion or strict type checking, some necessary attributes can be easily omitted or even misspelled.
Is it possible to fix my solution or should I better move to the macros?
I almost suggested here to open an issue regarding this problem. Because some time ago, there was a #:followWithAbstracts meta available for abstracts, which could be (or maybe was?) used to forward fields and call #:op(a.b) at the same time. But that's not really necessary, Haxe is powerful enough already.
abstract Binding<TClass>(TClass) {
public function new(source:TClass) { this = source; }
#:op(a.b) public function setField<T>(name:String, value:T) {
Reflect.setField(this, name, value);
// TODO notify handlers
trace("set: $name -> $value");
return value;
}
#:op(a.b) public function getField<T>(name:String):T {
trace("get: $name");
return cast Reflect.field(this, name);
}
}
#:forward
#:multiType
abstract Bindable<TClass>(TClass) {
public function new(source:TClass);
#:to function to(t:TClass) return new Binding(t);
}
We use here multiType abstract to forward fields, but resolved type is actually regular abstract. In effect, you have completion working and #:op(a.b) called at the same time.
You need #:forward meta on your abstract. However, this will not make auto-completion working unless you remove #:op(A.B) because it shadows forwarded fields.
EDIT: it seems that shadowing happened first time I added #:forward to your abstract, afterwards auto-completion worked just fine.
I have a content part that provides a begin timestamp and end timestamp option. These 2 fields are used to define a period of time in which the content item should be displayed.
I now have difficulties to implement a skip approach whereas content items should not be displayed / skipped when the period of time does not span the current time.
Digging in the source code and trying to find an entry point for my approach resulted in the following content handler
public class SkipContentHandler : Orchard.ContentManagement.Handlers.ContentHandler
{
protected override void BuildDisplayShape(Orchard.ContentManagement.Handlers.BuildDisplayContext aContext)
{
if (...) // my condition to process only content shapes which need to be skipped
{
aContext.Shape = null; // return null shape to skip it
}
}
}
This works but there are several side effects
I had to alter the source code of BuildDisplayContext as the Shape is normally read only
List shape may displayed a wrong pager when it contains content items with my content part because the Count() call in ContainerPartDriver.Display() is executed before BuildDisplay()
calling the URL of a content item that is skipped results in an exception because View(null) is abigious
So, what would be the correct approach here or is there any module in existence that does the job? I couldn't find one.
This is a quite complex task. There are several steps needed to achieve a proper skipping of display items:
Create the part correctly
There are a few pitfalls here as when coming to the task of adding a part view one might utilize Orchards date time editor in connection with the DateTime properties. But this brings a heck of a lot of additional issues to the table but these don't really relate to the question.
If someone is interested in how to use Orchards date time editor then i can post this code too, but for now it would only blow up the code unnecessarly.
So here we go, the part class...
public class ValidityPart : Orchard.ContentManagement.ContentPart<ValidityPartRecord>
{
// public
public System.DateTime? ValidFromUtc
{
get { return Retrieve(r => r.ValidFromUtc); }
set { Store(r => r.ValidFromUtc, value); }
}
...
public System.DateTime? ValidTillUtc
{
get { return Retrieve(r => r.ValidTillUtc); }
set { Store(r => r.ValidTillUtc, value); }
}
...
public bool IsContentItemValid()
{
var lUtcNow = System.DateTime.UtcNow;
return (ValidFromUtc == null || ValidFromUtc.Value <= lUtcNow) && (ValidTillUtc == null || ValidTillUtc.Value >= lUtcNow);
}
...
}
...and the record class...
public class ValidityPartRecord : Orchard.ContentManagement.Records.ContentPartRecord
{
// valid from value as UTC to use Orchard convention (see CommonPart table) and to be compatible with projections
// (date/time tokens work with UTC values, see https://github.com/OrchardCMS/Orchard/issues/6963 for a related issue)
public virtual System.DateTime? ValidFromUtc { get; set; }
// valid from value as UTC to use Orchard convention (see CommonPart table) and to be compatible with projections
// (date/time tokens work with UTC values, see https://github.com/OrchardCMS/Orchard/issues/6963 for a related issue)
public virtual System.DateTime? ValidTillUtc { get; set; }
}
Create a customized content query class
public class MyContentQuery : Orchard.ContentManagement.DefaultContentQuery
{
// public
public ContentQuery(Orchard.ContentManagement.IContentManager aContentManager,
Orchard.Data.ITransactionManager aTransactionManager,
Orchard.Caching.ICacheManager aCacheManager,
Orchard.Caching.ISignals aSignals,
Orchard.Data.IRepository<Orchard.ContentManagement.Records.ContentTypeRecord> aContentTypeRepository,
Orchard.IWorkContextAccessor aWorkContextAccessor)
: base(aContentManager, aTransactionManager, aCacheManager, aSignals, aContentTypeRepository)
{
mWorkContextAccessor = aWorkContextAccessor;
}
protected override void BeforeExecuteQuery(NHibernate.ICriteria aContentItemVersionCriteria)
{
base.BeforeExecuteQuery(aContentItemVersionCriteria);
// note:
// this method will be called each time a query for multiple items is going to be executed (e.g. content items of a container, layers, menus),
// this gives us the chance to add a validity criteria
var lWorkContext = mWorkContextAccessor.GetContext();
// exclude admin as content items should still be displayed / accessible when invalid as validity needs to be editable
if (lWorkContext == null || !Orchard.UI.Admin.AdminFilter.IsApplied(lWorkContext.HttpContext.Request.RequestContext))
{
var lUtcNow = System.DateTime.UtcNow;
// left outer join of ValidityPartRecord table as part is optional (not present on all content types)
var ValidityPartRecordCriteria = aContentItemVersionCriteria.CreateCriteria(
"ContentItemRecord.ValidityPartRecord", // string adopted from foreach loops in Orchard.ContentManagement.DefaultContentQuery.WithQueryHints()
NHibernate.SqlCommand.JoinType.LeftOuterJoin
);
// add validity criterion
ValidityPartRecordCriteria.Add(
NHibernate.Criterion.Restrictions.And(
NHibernate.Criterion.Restrictions.Or(
NHibernate.Criterion.Restrictions.IsNull("ValidFromUtc"),
NHibernate.Criterion.Restrictions.Le("ValidFromUtc", lUtcNow)
),
NHibernate.Criterion.Restrictions.Or(
NHibernate.Criterion.Restrictions.IsNull("ValidTillUtc"),
NHibernate.Criterion.Restrictions.Ge("ValidTillUtc", lUtcNow)
)
)
);
}
}
// private
Orchard.IWorkContextAccessor mWorkContextAccessor;
}
This essentially adds a left join of the validity part fields to the SQL query (content query) and extends the WHERE statement with the validity condition.
Please note that this step is only possible with the solution described the following issue: https://github.com/OrchardCMS/Orchard/issues/6978
Register the content query class
public class ContentModule : Autofac.Module
{
protected override void Load(Autofac.ContainerBuilder aBuilder)
{
aBuilder.RegisterType<MyContentQuery>().As<Orchard.ContentManagement.IContentQuery>().InstancePerDependency();
}
}
Create a customized content manager
public class ContentManager : Orchard.ContentManagement.DefaultContentManager
{
// public
public ContentManager(
Autofac.IComponentContext aContext,
Orchard.Data.IRepository<Orchard.ContentManagement.Records.ContentTypeRecord> aContentTypeRepository,
Orchard.Data.IRepository<Orchard.ContentManagement.Records.ContentItemRecord> aContentItemRepository,
Orchard.Data.IRepository<Orchard.ContentManagement.Records.ContentItemVersionRecord> aContentItemVersionRepository,
Orchard.ContentManagement.MetaData.IContentDefinitionManager aContentDefinitionManager,
Orchard.Caching.ICacheManager aCacheManager,
System.Func<Orchard.ContentManagement.IContentManagerSession> aContentManagerSession,
System.Lazy<Orchard.ContentManagement.IContentDisplay> aContentDisplay,
System.Lazy<Orchard.Data.ITransactionManager> aTransactionManager,
System.Lazy<System.Collections.Generic.IEnumerable<Orchard.ContentManagement.Handlers.IContentHandler>> aHandlers,
System.Lazy<System.Collections.Generic.IEnumerable<Orchard.ContentManagement.IIdentityResolverSelector>> aIdentityResolverSelectors,
System.Lazy<System.Collections.Generic.IEnumerable<Orchard.Data.Providers.ISqlStatementProvider>> aSqlStatementProviders,
Orchard.Environment.Configuration.ShellSettings aShellSettings,
Orchard.Caching.ISignals aSignals,
Orchard.IWorkContextAccessor aWorkContextAccessor)
: base(aContext, aContentTypeRepository, aContentItemRepository, aContentItemVersionRepository, aContentDefinitionManager, aCacheManager, aContentManagerSession,
aContentDisplay, aTransactionManager, aHandlers, aIdentityResolverSelectors, aSqlStatementProviders, aShellSettings, aSignals)
{
mWorkContextAccessor = aWorkContextAccessor;
}
public override ContentItem Get(int aId, Orchard.ContentManagement.VersionOptions aOptions, Orchard.ContentManagement.QueryHints aHints)
{
var lResult = base.Get(aId, aOptions, aHints);
if (lResult != null)
{
// note:
// the validity check is done here (after the query has been executed!) as changing base.GetManyImplementation() to
// apply the validity critera directly to the query (like in ContentQuery) will not work due to a second attempt to retrieve the
// content item from IRepository<> (see base.GetManyImplementation(), comment "check in memory") when the query
// returns no data (and the query should not return data when the validity critera is false)
//
// http://stackoverflow.com/q/37841249/3936440
var lWorkContext = mWorkContextAccessor.GetContext();
// exclude admin as content items should still be displayed / accessible when invalid as validity needs to be editable
if (lWorkContext == null || !Orchard.UI.Admin.AdminFilter.IsApplied(lWorkContext.HttpContext.Request.RequestContext))
{
var lValidityPart = lResult.As<ValidityPart>();
if (lValidityPart != null)
{
if (lValidityPart.IsContentItemValid())
{
// content item is valid
}
else
{
// content item is not valid, return null (adopted from base.Get())
lResult = null;
}
}
}
}
return lResult;
}
// private
Orchard.IWorkContextAccessor mWorkContextAccessor;
}
Steps 2-4 are needed when having content items whereas the content type has a Container and Containable part or even content items which are processed / displayed separately. Here you normally cannot customize the content query that is executed behind the scenes.
Steps 2-4 are not needed if you use the Projection module. But again, this brings a few other issues to the table as reported in this issue: https://github.com/OrchardCMS/Orchard/issues/6979
In Objective-C, I would normally use something like this:
static NSString *kViewTransformChanged = #"view transform changed";
// or
static const void *kViewTransformChanged = &kViewTransformChanged;
[clearContentView addObserver:self
forKeyPath:#"transform"
options:NSKeyValueObservingOptionNew
context:&kViewTransformChanged];
I have two overloaded methods to choose from to add an observer for KVO with the only difference being the context argument:
clearContentView.addObserver(observer: NSObject?, forKeyPath: String?, options: NSKeyValueObservingOptions, context: CMutableVoidPointer)
clearContentView.addObserver(observer: NSObject?, forKeyPath: String?, options: NSKeyValueObservingOptions, kvoContext: KVOContext)
With Swift not using pointers, I'm not sure how to dereference a pointer to use the first method.
If I create my own KVOContext constant for use with the second method, I wind up with it asking for this:
let test:KVOContext = KVOContext.fromVoidContext(context: CMutableVoidPointer)
EDIT: What is the difference between CMutableVoidPointer and KVOContext? Can someone give me an example how how to use them both and when I would use one over the other?
EDIT #2: A dev at Apple just posted this to the forums: KVOContext is going away; using a global reference as your context is the way to go right now.
There is now a technique officially recommended in the documentation, which is to create a private mutable variable and use its address as the context.
(Updated for Swift 3 on 2017-01-09)
// Set up non-zero-sized storage. We don't intend to mutate this variable,
// but it needs to be `var` so we can pass its address in as UnsafeMutablePointer.
private static var myContext = 0
// NOTE: `static` is not necessary if you want it to be a global variable
observee.addObserver(self, forKeyPath: …, options: [], context: &MyClass.myContext)
override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey: Any]?, context: UnsafeMutableRawPointer?) {
if context == &myContext {
…
}
else {
super.observeValue(forKeyPath: keyPath, of: object, change: change, context: context)
}
}
Now that KVOContext is gone in Xcode 6 beta 3, you can do the following. Define a global (i.e. not a class property) like so:
let myContext = UnsafePointer<()>()
Add an observer:
observee.addObserver(observer, forKeyPath: …, options: nil, context: myContext)
In the observer:
override func observeValueForKeyPath(keyPath: String!, ofObject object: AnyObject!, change: [NSObject : AnyObject]!, context: UnsafePointer<()>) {
if context == myContext {
…
} else {
super.observeValueForKeyPath(keyPath, ofObject: object, change: change, context: context)
}
}
Swift 4 - observing contentSize change on UITableViewController popover to fix incorrect size
I had been searching for an answer to change to a block based KVO because I was getting a swiftlint warning and it took me piecing quite a few different answers together to get to the right solution. Swiftlint warning:
Block Based KVO Violation: Prefer the new block based KVO API with keypaths when using Swift 3.2 or later. (block_based_kvo).
My use case was to present a popover controller attached to a button in a Nav bar in a view controller and then resize the popover once it's showing - otherwise it would be too big and not fitting the contents of the popover. The popover itself was a UITableViewController that contained static cells, and it was displayed via a Storyboard segue with style popover.
To setup the block based observer, you need the following code inside your popover UITableViewController:
// class level variable to store the statusObserver
private var statusObserver: NSKeyValueObservation?
// Create the observer inside viewWillAppear
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
statusObserver = tableView.observe(\UITableView.contentSize,
changeHandler: { [ weak self ] (theTableView, _) in self?.popoverPresentationController?.presentedViewController.preferredContentSize = theTableView.contentSize
})
}
// Don't forget to remove the observer when the popover is dismissed.
override func viewDidDisappear(_ animated: Bool) {
if let observer = statusObserver {
observer.invalidate()
statusObserver = nil
}
super.viewDidDisappear(animated)
}
I didn't need the previous value when the observer was triggered, so left out the options: [.new, .old] when creating the observer.
Update for Swift 4
Context is not required for block-based observer function and existing #keyPath() syntax is replaced with smart keypath to achieve swift type safety.
class EventOvserverDemo {
var statusObserver:NSKeyValueObservation?
var objectToObserve:UIView?
func registerAddObserver() -> Void {
statusObserver = objectToObserve?.observe(\UIView.tag, options: [.new, .old], changeHandler: {[weak self] (player, change) in
if let tag = change.newValue {
// observed changed value and do the task here on change.
}
})
}
func unregisterObserver() -> Void {
if let sObserver = statusObserver {
sObserver.invalidate()
statusObserver = nil
}
}
}
Complete example using Swift:
//
// AppDelegate.swift
// Photos-MediaFramework-swift
//
// Created by Phurg on 11/11/16.
//
// Displays URLs for all photos in Photos Library
//
// #see http://stackoverflow.com/questions/30144547/programmatic-access-to-the-photos-library-on-mac-os-x-photokit-photos-framewo
//
import Cocoa
import MediaLibrary
// For KVO: https://developer.apple.com/library/content/documentation/Swift/Conceptual/BuildingCocoaApps/AdoptingCocoaDesignPatterns.html#//apple_ref/doc/uid/TP40014216-CH7-ID12
private var mediaLibraryLoaded = 1
private var rootMediaGroupLoaded = 2
private var mediaObjectsLoaded = 3
#NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate {
#IBOutlet weak var window: NSWindow!
var mediaLibrary : MLMediaLibrary!
var allPhotosAlbum : MLMediaGroup!
func applicationDidFinishLaunching(_ aNotification: Notification) {
NSLog("applicationDidFinishLaunching:");
let options:[String:Any] = [
MLMediaLoadSourceTypesKey: MLMediaSourceType.image.rawValue, // Can't be Swift enum
MLMediaLoadIncludeSourcesKey: [MLMediaSourcePhotosIdentifier], // Array
]
self.mediaLibrary = MLMediaLibrary(options:options)
NSLog("applicationDidFinishLaunching: mediaLibrary=%#", self.mediaLibrary);
self.mediaLibrary.addObserver(self, forKeyPath:"mediaSources", options:[], context:&mediaLibraryLoaded)
NSLog("applicationDidFinishLaunching: added mediaSources observer");
// Force load
self.mediaLibrary.mediaSources?[MLMediaSourcePhotosIdentifier]
NSLog("applicationDidFinishLaunching: done");
}
override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
NSLog("observeValue: keyPath=%#", keyPath!)
let mediaSource:MLMediaSource = self.mediaLibrary.mediaSources![MLMediaSourcePhotosIdentifier]!
if (context == &mediaLibraryLoaded) {
NSLog("observeValue: mediaLibraryLoaded")
mediaSource.addObserver(self, forKeyPath:"rootMediaGroup", options:[], context:&rootMediaGroupLoaded)
// Force load
mediaSource.rootMediaGroup
} else if (context == &rootMediaGroupLoaded) {
NSLog("observeValue: rootMediaGroupLoaded")
let albums:MLMediaGroup = mediaSource.mediaGroup(forIdentifier:"TopLevelAlbums")!
for album in albums.childGroups! {
let albumIdentifier:String = album.attributes["identifier"] as! String
if (albumIdentifier == "allPhotosAlbum") {
self.allPhotosAlbum = album
album.addObserver(self, forKeyPath:"mediaObjects", options:[], context:&mediaObjectsLoaded)
// Force load
album.mediaObjects
}
}
} else if (context == &mediaObjectsLoaded) {
NSLog("observeValue: mediaObjectsLoaded")
let mediaObjects:[MLMediaObject] = self.allPhotosAlbum.mediaObjects!
for mediaObject in mediaObjects {
let url:URL? = mediaObject.url
// URL does not extend NSObject, so can't be passed to NSLog; use string interpolation
NSLog("%#", "\(url)")
}
}
}
}
The Goal is to have a list of options (that a user can chose through radio buttons) in one place(for eg: a yaml config file). No other place should have this list hard-coded
I've done something similar to create select elements, and I think enums worked just fine. Doing radio buttons should be very similar. I've set it up so that the labels can be defined in the messages file. I'm going to try to excerpt the relevant portions from my larger auto-form-generation code (using FastTags) the best I can. It's a bit heavy for this one case but it makes sense in the larger system.
I use the tag like #{form.selector 'order.status' /}, which looks find the variable named order in the template, sees that status is declared as public Status status, and then goes to find all the values of the Status enum and generate options for them in the select element.
First, I use a FieldContext object which just contains a bunch of info that's used by the other code to determine what to generate along with some utility methods:
public class FieldContext {
public final Map<?,?> args;
public final ExecutableTemplate template;
public final int fromLine;
public Class clazz = null;
public Field field = null;
public Object object = null;
public Object value = null;
private Map<String,String> attrs = new HashMap<String,String>();
private Map<String,Boolean> printed = new HashMap<String,Boolean>();
private List<Option> options;
...
Then I have this in another helper class (its info gets added to the FieldContext):
public List<Option> determineOptions(FieldContext context) {
List<Option> options = new ArrayList<Option>();
if (context.field.getType().isEnum()) {
for (Object option : context.field.getType().getEnumConstants()) {
options.add(new Option(option.toString(), Message.get(option.toString())));
}
}
return options;
}
then the tag declaration is
public static void _selector(Map<?,?> args, Closure body, PrintWriter out, ExecutableTemplate template, int fromLine) {
String field_name = args.get("arg").toString();
TagContext.current().data.put("name", field_name);
SelectHelper helper = HelperFactory.getHelper(SelectHelper.class);
try {
FieldContext context = new FieldContext(field_name, args, template, fromLine);
helper.autoconfigure(context);
TagContext.current().data.put("selected", helper.determineValue(context));
out.print("<div class=\"formutil-field formutil-selector\">");
out.print("<label for=\"" + context.getAttr("id") + "\">");
out.print(helper.findOrCreateLabel(context));
out.print("</label>");
out.print("<select");
context.printAttribute(out, "id", "name");
out.print(">");
if (context.hasOptions()) {
for (Option option : context.getOptions()) {
out.print("<option value=\"" + option.value + "\">" + option.label + "</option>");
}
}
out.print("</select>");
context.printErrorIfPresent(out);
context.printValidationHints(out);
out.println("</div>");
}
...
}