I'm having a hard time with a selectManyCheckbox.
Basically what I am doing is loading a List of Categories in a selectManyCheckbox type controller (have done this either with a List or with a List with convertEntity). My problem is with the selected elements (value="#{cardListProvider.categoriesHolder.selectedCategories}"). After some reading I understand it also has to be a List, but what kind? And how can I set the selected categories? I'm not saving them in DB but I need to run some action in the bean with them!
Here's what I have:
<h:selectManyCheckbox id="supportCategoryCardFilter"
value="#{cardListProvider.categoriesHolder.selectedCategories}" styleClass="greyText" required="false" >
<s:selectItems var="filterList" value="#{cardListProvider.categoriesList}" label="#{filterList.label}" />
<a:support id="supportCategoryCardFilter2" event="onchange"
reRender="someHolder, categoriesPanel" eventsQueue="onchange" action="#{cardListProvider.findCards(cardListProvider.categoriesHolder.selectedCategories)}" />
</h:selectManyCheckbox>
I have wasted several hours with this... Can anyone help me?
Thank you
You can bind to a String[] array like so:
public class CheckSelector {
private String[] chosen;
public String[] getChosen() { return chosen; }
public void setChosen(String[] chosen) { this.chosen = chosen; }
public SelectItem[] getChoices() {
return new SelectItem[] { new SelectItem("1"), new SelectItem("2"),
new SelectItem("3") };
}
}
The value of the selectManyCheckbox should be bound to chosen. Alternatively, you can use a List:
public class CheckSelector {
private List<String> chosen;
public List<String> getChosen() { return chosen; }
public void setChosen(List<String> chosen) { this.chosen = chosen; }
public List<SelectItem> getChoices() {
return Arrays.asList(new SelectItem("1"), new SelectItem("2"),
new SelectItem("3"));
}
}
The exact rules for value support are listed in the javadoc:
If the component has an attached Converter, use it.
If not, look for a ValueExpression for value (if any). The ValueExpression must point to something that is:
An array of primitives (such as int[]). Look up the registered by-class Converter for this primitive type.
An array of objects (such as Integer[] or String[]). Look up the registered by-class Converter for the underlying element type.
A java.util.List. Assume that the element type is java.lang.String, so no conversion is required.
If for any reason a Converter cannot be found, assume the type to be a String array.
I see you are using Seam so no need to use Strings or any primitive type, you can bind directly to List. You just have to add another tag inside your selectManyCheckbox component which is and it will automatically do everything.
Better than doing all by yourself, check Seam documentation
http://docs.jboss.org/seam/2.2.0.GA/reference/en-US/html/controls.html#d0e28378
Related
I am working on Managedbeans and JSF. As shown below that my ManagedBean contains all the requirements that are required for the JSF to get the value. I have initialised my dropdown list as below. In selectOneMenu, I have chosen the country as a string where it will store the value selected by the dropdown list and the dropdown list will bring up the list that I declared in the Beans.
Unfortunately, it is not happening like that. Every time dropdown renders it gives me an empty value. I have spent days on it but cannot figure out the exact solution to it. I have cleaned my server, build workspace and also change servers but nothing is working.
** ManagedBean_list **
private List<String> listCountry;
private String country;
public void tada(){
listCountry=Arrays.asList("India", "pakisatan","America");
}
public List<String> getListCountry() {
return listCountry;
}
public void setListCountry(List<String> listCountry) {
this.listCountry = listCountry;
}
public String getCountry() {
return country;
}
public void setCountry(String country) {
this.country = country;
}
JSF
<p:selectOneMenu id="country" value="#{loginBeans.country}">
<f:selectItems value="#{loginBeans.listCountry}" />
</p:selectOneMenu>
Your help is appreciated. Empty dropdown list image
enter image description here
Which bean annotation are you using? You say "Managedbeans", but the source you posted does not show the entire bean, or does it? Check to make sure you are not mixing old style JSF managed bean annotations with CDI annotations.
The issue is that on initialization, the list is not being called up. I resolved it by including the list function inside the constructor of managed beans class. so that when the constructor fired up. It also generates the dropdown list.
Either convert your listCountry to a
private Map<String, String> listCountry = new HashMap<>();
listCountry.put("India", "India");
listCountry.put("Pakistan", "Pakistan");
listCountry.put("America", "America");
or
private List<SelectItem> listCountry = new ArrayList<>();
listCountry.add(new SelectItem("India", "India"));
listCountry.add(new SelectItem("Pakistan", "Pakistan"));
listCountry.add(new SelectItem("America","America"));
I am creating a web application, where you have to read a list of objects / entities from a DB and populate it in a JSF <h:selectOneMenu>. I am unable to code this. Can someone show me how to do it?
I know how to get a List<User> from the DB. What I need to know is, how to populate this list in a <h:selectOneMenu>.
<h:selectOneMenu value="#{bean.name}">
...?
</h:selectOneMenu>
Based on your question history, you're using JSF 2.x. So, here's a JSF 2.x targeted answer. In JSF 1.x you would be forced to wrap item values/labels in ugly SelectItem instances. This is fortunately not needed anymore in JSF 2.x.
Basic example
To answer your question directly, just use <f:selectItems> whose value points to a List<T> property which you preserve from the DB during bean's (post)construction. Here's a basic kickoff example assuming that T actually represents a String.
<h:selectOneMenu value="#{bean.name}">
<f:selectItems value="#{bean.names}" />
</h:selectOneMenu>
with
#ManagedBean
#RequestScoped
public class Bean {
private String name;
private List<String> names;
#EJB
private NameService nameService;
#PostConstruct
public void init() {
names = nameService.list();
}
// ... (getters, setters, etc)
}
Simple as that. Actually, the T's toString() will be used to represent both the dropdown item label and value. So, when you're instead of List<String> using a list of complex objects like List<SomeEntity> and you haven't overridden the class' toString() method, then you would see com.example.SomeEntity#hashcode as item values. See next section how to solve it properly.
Also note that the bean for <f:selectItems> value does not necessarily need to be the same bean as the bean for <h:selectOneMenu> value. This is useful whenever the values are actually applicationwide constants which you just have to load only once during application's startup. You could then just make it a property of an application scoped bean.
<h:selectOneMenu value="#{bean.name}">
<f:selectItems value="#{data.names}" />
</h:selectOneMenu>
Complex objects as available items
Whenever T concerns a complex object (a javabean), such as User which has a String property of name, then you could use the var attribute to get hold of the iteration variable which you in turn can use in itemValue and/or itemLabel attribtues (if you omit the itemLabel, then the label becomes the same as the value).
Example #1:
<h:selectOneMenu value="#{bean.userName}">
<f:selectItems value="#{bean.users}" var="user" itemValue="#{user.name}" />
</h:selectOneMenu>
with
private String userName;
private List<User> users;
#EJB
private UserService userService;
#PostConstruct
public void init() {
users = userService.list();
}
// ... (getters, setters, etc)
Or when it has a Long property id which you would rather like to set as item value:
Example #2:
<h:selectOneMenu value="#{bean.userId}">
<f:selectItems value="#{bean.users}" var="user" itemValue="#{user.id}" itemLabel="#{user.name}" />
</h:selectOneMenu>
with
private Long userId;
private List<User> users;
// ... (the same as in previous bean example)
Complex object as selected item
Whenever you would like to set it to a T property in the bean as well and T represents an User, then you would need to bake a custom Converter which converts between User and an unique string representation (which can be the id property). Do note that the itemValue must represent the complex object itself, exactly the type which needs to be set as selection component's value.
<h:selectOneMenu value="#{bean.user}" converter="#{userConverter}">
<f:selectItems value="#{bean.users}" var="user" itemValue="#{user}" itemLabel="#{user.name}" />
</h:selectOneMenu>
with
private User user;
private List<User> users;
// ... (the same as in previous bean example)
and
#ManagedBean
#RequestScoped
public class UserConverter implements Converter {
#EJB
private UserService userService;
#Override
public Object getAsObject(FacesContext context, UIComponent component, String submittedValue) {
if (submittedValue == null || submittedValue.isEmpty()) {
return null;
}
try {
return userService.find(Long.valueOf(submittedValue));
} catch (NumberFormatException e) {
throw new ConverterException(new FacesMessage(String.format("%s is not a valid User ID", submittedValue)), e);
}
}
#Override
public String getAsString(FacesContext context, UIComponent component, Object modelValue) {
if (modelValue == null) {
return "";
}
if (modelValue instanceof User) {
return String.valueOf(((User) modelValue).getId());
} else {
throw new ConverterException(new FacesMessage(String.format("%s is not a valid User", modelValue)), e);
}
}
}
(please note that the Converter is a bit hacky in order to be able to inject an #EJB in a JSF converter; normally one would have annotated it as #FacesConverter(forClass=User.class), but that unfortunately doesn't allow #EJB injections)
Don't forget to make sure that the complex object class has equals() and hashCode() properly implemented, otherwise JSF will during render fail to show preselected item(s), and you'll on submit face Validation Error: Value is not valid.
public class User {
private Long id;
#Override
public boolean equals(Object other) {
return (other != null && getClass() == other.getClass() && id != null)
? id.equals(((User) other).id)
: (other == this);
}
#Override
public int hashCode() {
return (id != null)
? (getClass().hashCode() + id.hashCode())
: super.hashCode();
}
}
Complex objects with a generic converter
Head to this answer: Implement converters for entities with Java Generics.
Complex objects without a custom converter
The JSF utility library OmniFaces offers a special converter out the box which allows you to use complex objects in <h:selectOneMenu> without the need to create a custom converter. The SelectItemsConverter will simply do the conversion based on readily available items in <f:selectItem(s)>.
<h:selectOneMenu value="#{bean.user}" converter="omnifaces.SelectItemsConverter">
<f:selectItems value="#{bean.users}" var="user" itemValue="#{user}" itemLabel="#{user.name}" />
</h:selectOneMenu>
See also:
Our <h:selectOneMenu> wiki page
View-Page
<h:selectOneMenu id="selectOneCB" value="#{page.selectedName}">
<f:selectItems value="#{page.names}"/>
</h:selectOneMenu>
Backing-Bean
List<SelectItem> names = new ArrayList<SelectItem>();
//-- Populate list from database
names.add(new SelectItem(valueObject,"label"));
//-- setter/getter accessor methods for list
To display particular selected record, it must be one of the values in the list.
Roll-your-own generic converter for complex objects as selected item
The Balusc gives a very useful overview answer on this subject. But there is one alternative he does not present: The Roll-your-own generic converter that handles complex objects as the selected item. This is very complex to do if you want to handle all cases, but pretty simple for simple cases.
The code below contains an example of such a converter. It works in the same spirit as the OmniFaces SelectItemsConverter as it looks through the children of a component for UISelectItem(s) containing objects. The difference is that it only handles bindings to either simple collections of entity objects, or to strings. It does not handle item groups, collections of SelectItems, arrays and probably a lot of other things.
The entities that the component binds to must implement the IdObject interface. (This could be solved in other way, such as using toString.)
Note that the entities must implement equals in such a way that two entities with the same ID compares equal.
The only thing that you need to do to use it is to specify it as converter on the select component, bind to an entity property and a list of possible entities:
<h:selectOneMenu value="#{bean.user}" converter="selectListConverter">
<f:selectItem itemValue="unselected" itemLabel="Select user..."/>
<f:selectItem itemValue="empty" itemLabel="No user"/>
<f:selectItems value="#{bean.users}" var="user" itemValue="#{user}" itemLabel="#{user.name}" />
</h:selectOneMenu>
Converter:
/**
* A converter for select components (those that have select items as children).
*
* It convertes the selected value string into one of its element entities, thus allowing
* binding to complex objects.
*
* It only handles simple uses of select components, in which the value is a simple list of
* entities. No ItemGroups, arrays or other kinds of values.
*
* Items it binds to can be strings or implementations of the {#link IdObject} interface.
*/
#FacesConverter("selectListConverter")
public class SelectListConverter implements Converter {
public static interface IdObject {
public String getDisplayId();
}
#Override
public Object getAsObject(FacesContext context, UIComponent component, String value) {
if (value == null || value.isEmpty()) {
return null;
}
return component.getChildren().stream()
.flatMap(child -> getEntriesOfItem(child))
.filter(o -> value.equals(o instanceof IdObject ? ((IdObject) o).getDisplayId() : o))
.findAny().orElse(null);
}
/**
* Gets the values stored in a {#link UISelectItem} or a {#link UISelectItems}.
* For other components returns an empty stream.
*/
private Stream<?> getEntriesOfItem(UIComponent child) {
if (child instanceof UISelectItem) {
UISelectItem item = (UISelectItem) child;
if (!item.isNoSelectionOption()) {
return Stream.of(item.getValue());
}
} else if (child instanceof UISelectItems) {
Object value = ((UISelectItems) child).getValue();
if (value instanceof Collection) {
return ((Collection<?>) value).stream();
} else {
throw new IllegalStateException("Unsupported value of UISelectItems: " + value);
}
}
return Stream.empty();
}
#Override
public String getAsString(FacesContext context, UIComponent component, Object value) {
if (value == null) return null;
if (value instanceof String) return (String) value;
if (value instanceof IdObject) return ((IdObject) value).getDisplayId();
throw new IllegalArgumentException("Unexpected value type");
}
}
I'm doing it like this:
Models are ViewScoped
converter:
#Named
#ViewScoped
public class ViewScopedFacesConverter implements Converter, Serializable
{
private static final long serialVersionUID = 1L;
private Map<String, Object> converterMap;
#PostConstruct
void postConstruct(){
converterMap = new HashMap<>();
}
#Override
public String getAsString(FacesContext context, UIComponent component, Object object) {
String selectItemValue = String.valueOf( object.hashCode() );
converterMap.put( selectItemValue, object );
return selectItemValue;
}
#Override
public Object getAsObject(FacesContext context, UIComponent component, String selectItemValue){
return converterMap.get(selectItemValue);
}
}
and bind to component with:
<f:converter binding="#{viewScopedFacesConverter}" />
If you will use entity id rather than hashCode you can hit a collision- if you have few lists on one page for different entities (classes) with the same id
Call me lazy but coding a Converter seems like a lot of unnecessary work. I'm using Primefaces and, not having used a plain vanilla JSF2 listbox or dropdown menu before, I just assumed (being lazy) that the widget could handle complex objects, i.e. pass the selected object as is to its corresponding getter/setter like so many other widgets do. I was disappointed to find (after hours of head scratching) that this capability does not exist for this widget type without a Converter. In fact if you supply a setter for the complex object rather than for a String, it fails silently (simply doesn't call the setter, no Exception, no JS error), and I spent a ton of time going through BalusC's excellent troubleshooting tool to find the cause, to no avail since none of those suggestions applied. My conclusion: listbox/menu widget needs adapting that other JSF2 widgets do not. This seems misleading and prone to leading the uninformed developer like myself down a rabbit hole.
In the end I resisted coding a Converter and found through trial and error that if you set the widget value to a complex object, e.g.:
<p:selectOneListbox id="adminEvents" value="#{testBean.selectedEvent}">
... when the user selects an item, the widget can call a String setter for that object, e.g. setSelectedThing(String thingString) {...}, and the String passed is a JSON String representing the Thing object. I can parse it to determine which object was selected. This feels a little like a hack, but less of a hack than a Converter.
This question already has answers here:
Validation Error: Value is not valid
(3 answers)
Closed 6 years ago.
I am using the managedBean userHome in requestScope, in which the entity 'user' is going to be persist.
The user has the leader column which is mapped in ManyToOne relation.My Code looks like this
#ManagedBean
#RequestScoped
public class UserHome {
private User user = new User();
// Getters and Setters
private List<SelectItem> selectItems = new ArrayList<SelectItem>();
public UserHome() {
for(User user: availableLeaders) {
selectItems.add(new SelectItem(user.getName(), user));
}
}
public void persis();
}
User.java
public class User {
#Id
#Column
private Integer id;
#Column
privat String name;
#ManyToOne
private User leader;
}
I am trying to get the value of this leader through h:selectOneMenu like this
<h:selectOneMenu value="#{userHome.user.leader}" converter="userConverter">
<f:selectItems value="#{userHome.selectItems}"/>
</h:selectOneMenu>
My converter looks like this
#FacesConverter(forClass = User.class, value="userConverter")
public class UserConverter implements Converter {
private Map<String, User> userValues = new HashMap<String, User>();
public UserConverter() {
init();
}
#Override
public Object getAsObject(FacesContext context, UIComponent component,
String value) {
return userValues.get(value);
}
#Override
public String getAsString(FacesContext context, UIComponent component, Object value) {
System.out.println("RAJASEKARAN "+value);
return ((User)value).getName();
}
public void init() {
UserHome userHome = new UserHome();
for(User user:userHome.availableLeaders()) {
userValues.put(user.getName(), user);
}
}
}
While try to save the user I am getting the error UserEdit:j_idt18: Validation Error: Value is not valid
Adding to BalusC's answer: after the postback, you need to make sure that the User instances are either exactly the same ones as you used for rendering the select items, or that you implement equals for your User class.
The code doesn't show where availableLeaders comes from, but if this is fetched from a DB on-demand, then the converter will not convert to the exact same object instance that's in the list that JSF resolves via #{userHome.selectItems}.
After the conversion, JSF will check whether the converted instance can be found in that list using the equals() method.
You've constructed the SelectItem the wrong way. As per the class' documentation, the 1st argument should represent the item value (which is to be converted and submitted) and the 2nd argument should represent the item label (which is to be displayed in list). But you specified them the other way round.
Fix it accordingly:
selectItems.add(new SelectItem(user, user.getName()));
If that still doesn't fix the problem, then it means that the equals() method of User class is not (properly) implemented. JSF will use it to validate the selected User against any of the item values of the list after conversion.
Unrelated to the concrete problem, it may be useful to know that <f:selectItems> in JSF2 offers you the possibility to build the list without the need to build a list of SelectItem manually. Here's an example which achieves exactly the same:
<f:selectItems value="#{userHome.availableLeaders}" var="user"
itemValue="#{user}" itemLabel="#{user.name}" />
This allows you to get rid of the additional selectItems property and the loop in the bean constructor.
I'm new to facelets and I have generated a project using netbeans but I struggling with the tag.
I have
<h:selectOneMenu id="country" value="#{organisation.organisation.country}" title="Country" >
<f:selectItems value="#{country.countryItemsAvailableSelectOne}"/>
</h:selectOneMenu>
In the select I get classpath.Country[iso=GB] which I can see is an object but I really want to see the the country.prinableName value.
I've looked at this for half a day and have drawn a blank
Thanks for any help
Since you're talking about Facelets, I'll assume JSF 2.x.
To start, HTML is one and all String. JSF generates HTML. By default, non-String Java objects are by toString() method converted to their String representation while JSF generates the HTML. To properly convert between those Java objects and String, you need a Converter.
I assume that your Country object has already the equals() method properly implemented, otherwise validation will later fail with "Validation error: Value not valid" because the selected object doesn't return true on testing the equals() for any of the available items.
I'll also make a little change in the naming since #{country} is a confusing managed bean name because it does apparently not represent an instance of the Country class. I'll call it Data which should hold application wide data.
#ManagedBean
#ApplicaitionScoped
public class Data {
private static final List<Country> COUNTRIES = populateItSomehow();
public List<Country> getCountries() {
return COUNTRIES;
}
// ...
}
I'll assume that the Country class has two properties code and name. I'll assume that the managed bean which receives the selected country has a private Country country property. In your <f:selectItems>, you need to loop over #{data.countries} and specify the country object as item value and the country name as item label.
<h:selectOneMenu value="#{bean.country}">
<f:selectItems value="#{data.countries}" var="country" itemValue="#{country}" itemLabel="#{country.name}" />
</h:selectOneMenu>
Now, you need to create a Converter for the Country class. We'll convert based on the country code which is unique for every country (right?). In the getAsString() you implement code which converts the Java object to its unique String representation which is to be used in HTML. In getAsObject() you implement code which converts the unique HTML String representation back to the Java object.
#FacesConverter(forClass=Country.class)
public class CountryConverter implements Converter {
#Override
public String getAsString(FacesContext context, UIComponent component, Object value) {
return (value instanceof Country) ? ((Country) value).getCode() : null;
}
#Override
public Object getAsObject(FacesContext context, UIComponent component, String value) {
if (value == null) {
return null;
}
Data data = context.getApplication().evaluateExpressionGet(context, "#{data}", Data.class);
for (Country country : data.getCountries()) {
if (country.getCode().equals(value)) {
return country;
}
}
throw new ConverterException(new FacesMessage(String.format("Cannot convert %s to Country", value)));
}
}
The #FacesConverter will register it automatically in JSF and JSF will automatically use it whenever it encounters a value expression of the Country type. Ultimately, you end up with country code as item value and country name as item label. JSF will convert the submitted country code back to a fullworthy Country object upon form submission.
In JSF 1.x the principle is not much different. In this blog you can find two basic kickoff examples: Objects in h:selectOneMenu.
What happened to you, selectOneMenu call the toString() method for all given objects.
You've to use selectitems or a simple converter to manage that. A very simple example:
price.xhtml:
<h:selectOneMenu id="priceMenu" value="#{priceBean.selectedPrice}">
<f:selectItems value="#{priceBean.prices}" />
</h:selectOneMenu>
PriceBean.java:
..
private String selectedPrice;
..
public String getSelectedPrice() {
return selectedPrice;
}
public void setSelectedPrice(String newPrice) {
selectedPrice = newPrice;
}
..
public List<SelectItem> getPrices() {
List<SelectItem> retVal = new ArrayList<SelectItem>();
retVal.add(new SelectItem("2"));
retVal.add(new SelectItem("4"));
retVal.add(new SelectItem("6"));
return retVal;
}
Further informations about the SelectItem. If you want to use a specially object directly, for example an object called Price, you have to use a converter. Here an example is shown and here.
If you add editable="true" in your
<h:selectOneMenu value="#{bean.country}">
Then you'll get an unexpected String value (not from getAsString()) in the converter method:
public Object getAsObject(FacesContext context, UIComponent component, String value) { }
I have tried working with the grouped selections with something like this :
<h:selectOneMenu value="#{selectionLabBean.oneSelectMenuGroup}"
id="SelectOneMenuGroup" >
<f:selectItems value="#{selectionLabBean.heroGroupList}" />
</h:selectOneMenu>
<p:message for="SelectOneMenuGroup" />
where the heroGroupList is something like this :
SelectItem[] heroArr = new SelectItem[] {
new SelectItem("Paladin"),
...
};
heroListWithGrouping.add(
new SelectItemGroup("Human",
"A collection of human race Heroes",
false,
heroArr
)
);
.....
And i'm left wondering if i can do this kind of grouping with POJOs instead of SelectItem objects ?
If i couldnt achieve this, i think i have to somehow convert my domain objects or my query results into arrays of SelectItem to make it work.
Any ideas ?
That's indeed not possible when you want to use SelectItemGroup. You need to convert from collection of POJO's to List<SelectItem> in a double for-loop during bean's (post)construction.
#PostConstruct
public void init() {
List<HeroRace> heroRaces = getItSomehowFromDatabase();
this.heroGroupList = new ArrayList<SelectItem>();
for (HeroRace heroRace : heroRaces) {
SelectItemGroup group = new SelectItemGroup(heroRace.getName()); // Human, etc
List<SelectItem> heroes = new ArrayList<SelectItem>();
for (Hero hero : heroRace.getHeroes()) {
heroes.add(new SelectItem(hero.getName()); // Paladin, etc
}
group.setSelectItems(heroes.toArray(new SelectItem[heroes.size()]));
this.heroGroupList.add(group);
}
}
You could also use Hero as item value
heroes.add(new SelectItem(hero, hero.getName()); // Paladin, etc
so that you can bind #{selectionLabBean.oneSelectMenuGroup} to a Hero type instead of String. But then you need to supply a Converter. That part is already answered by Amorfis.
Yes, you can return List or array of POJOs instead of SelectItems. You'll need converter for this to work, but it's not a big deal. So, converter first:
#FacesConverter(forClass=Hero.class)
public class HeroConverter implements Converter {
#Override
public Object getAsObject(FacesContext context, UIComponent component, String value) {
return new Hero(value);
}
#Override
public String getAsString(FacesContext context, UIComponent component, Object value) {
return ((Hero)value).getName();
}
}
Now if you return list of Heroes to <f:selectItems>, you have options in HTML where label is Hero.toString(), and value is returned from HeroConverter.getAsString().
One more thing. If you submit some value for this selection, JSF converts it to object and checks (by equals() method) if this object was in list of objects for selection. So in case above, you'll need to override equals() in Hero to check if names are equal. Another solution is not to create new instance in getAsObject, but to keep somewhere list of available Heroes and return this list to <f:selectionItems> and return object from this list in getAsObject().