Let's suppose I have following structure:
1) Managed Bean:
#ViewScoped
#ManagedBean
public class TestBean {
private Test test;
//getters/setters
}
2) Test class:
public class Test {
private String attribute;
//gets/sets
}
3) XHTML
<p:inputText id="test" value="#{testBean.test.atribute}" />
Now, I know there is a way to find and get component instance:
UIComponent c = view.findComponent(s);
From UIComponent, how do I get the type bound to component?
What I need is to get full qualified class name from what is set as "value" attribute in component. Something like: package.Test.attribute.
UIComponent offers getValueExpression("attributeName")
sample :
UIViewRoot viewRoot = Faces.getViewRoot();
UIComponent component= viewRoot.findComponent("x");
ValueExpression value = component.getValueExpression("value");
Class<?> expectedType = value.getType(Faces.getELContext());
NB:Faces here is from Omnifaces, which is a "Collection of utility methods for the JSF API that are mainly shortcuts for obtaining stuff from the thread local FacesContext. "
excepts from getType() javadoc
public abstract Class getType(ELContext context) Evaluates the
expression relative to the provided context, and returns the most
general type that is acceptable for an object to be passed as the
value parameter in a future call to the setValue(javax.el.ELContext. java.lang.Object) method. This is not always the same as
getValue().getClass(). For example, in the case of an expression that
references an array element, the getType method will return the
element type of the array, which might be a superclass of the type of
the actual element that is currently in the specified array element.
For MethodExpression read this.
I have the following domain class:
package com.example
class Location {
String state
def getStatesList(){
def states = ['AL','AK','AZ','AR','CA','CO','CT',
'DC','DE','FL','GA','HI','ID','IL','IN','IA',
'KS','KY','LA','ME','MD','MA','MI','MN','MS',
'MO','MT','NE','NV','NH','NJ','NM','NY','NC',
'ND','OH','OK','OR','PA','RI','SC','SD','TN',
'TX','UT','VT','VA','WA','WV','WI','WY']
return states
}
}
In my gsp, I am trying to display the state list in a select dropdown as such
<g:select name="location.state" class="form-control" from="${com.example.Location?.getStatesList()}" value="${itemInstance?.location?.state}" noSelection="['': '']" />
In doing so, I am receiving "missing method exception"
If I change the method with list, I no longer receive the error, but I don't want that.
from="${com.example.Location?.list()}" // works
from="${com.example.Location?.getStatesList()}" // does not work
Any help is greatly appreciated.
As dmahaptro said, you can correct this issue by making getStatesList() a static method.
class Location {
String state
static List<String> getStatesList() {
['AL','AK','AZ','AR','CA','CO','CT',
'DC','DE','FL','GA','HI','ID','IL','IN','IA',
'KS','KY','LA','ME','MD','MA','MI','MN','MS',
'MO','MT','NE','NV','NH','NJ','NM','NY','NC',
'ND','OH','OK','OR','PA','RI','SC','SD','TN',
'TX','UT','VT','VA','WA','WV','WI','WY']
}
}
Then you'll be able to execute Location.statesList or Location.getStatesList().
Alternative
I think a cleaner alternative is using a final constant:
class Location {
String state
static final List<String> STATES =
['AL','AK','AZ','AR','CA','CO','CT',
'DC','DE','FL','GA','HI','ID','IL','IN','IA',
'KS','KY','LA','ME','MD','MA','MI','MN','MS',
'MO','MT','NE','NV','NH','NJ','NM','NY','NC',
'ND','OH','OK','OR','PA','RI','SC','SD','TN',
'TX','UT','VT','VA','WA','WV','WI','WY']
}
Then you can access the list the same way: Location.STATES. The difference is that the all-caps name implies a value that does not change (and does not require accessing the database).
list() is a method on the domain object's metaclass. In order to do what you're trying to do you'd have to instantiate an instance of Location (or add to the metaclass). I'd personally use an Enum instead if I were you.
You have to make getStatesList() static because you are not accessing an instance of the Location class.
'm trying to create a reusable link class that extends Link. I have a webpage with about 7 menu items and I'm using inheritance for my application. I want to create a reusable link class to shorten the length of my code..
As of now the link creates and runs fine when I add(new Link....) as an anonymous class inside oninitialize().
The custom link class (which is an inner class of the base page) works fine when I hard code the instance of the new page to go to, and assign it to a "Page" reference, then pass it into setResponsePage();
The problem is, I'm passing trying to be able to pass object through the constructor generically. When I pass it through the constructor, and try to travel to the new page, I get a session has expired.
I've tried using generics for the class, and I've also tried just declaring a Page reference as a parameter value. Am I supposed to use some sort of Model? Or can someone provide an example of how to do this? I want to be able to use this custom link class to add new links for the 7 menu items, which each have there own class...
Code that works:
add(new Link("userPageLink")
{
public void onClick()
{
pageTitle = "User";
Page next = new UserPage();
setResponsePage(next);
}
});
Modified code that gives page expired upon click:
public class CustomLinkToNewPage extends Link
{
private String title;
private Page next;
public CustomLinkToNewPage(String id, String title, Page newPage)
{
super(id);
next = newPage;
this.title = title;
}
#Override
public void onClick()
{
SSAPage.pageTitle = title;
setResponsePage(next);
}
}
This might be due to the fact that in the first version you crate the Page object when the onClick method of the Link object is called and in the second version, the Page object is created on Page-construction (way earlier).
You might get the result if you pass the Pageclass of the responsepage instead on an instance.
Component features setters for these either with
public final <C extends IRequestablePage> void setResponsePage(java.lang.Class<C> cls, PageParameters parameters)
or without parameters.
public final <C extends IRequestablePage> void setResponsePage(java.lang.Class<C> cls)
See Javadoc for more information.
I ended up doing:
public class CustomLinkToNewPage<T extends SSAPage> extends Link
SSAPage is my base page that extends WebPage... So any object passed in to this class's constructor must extend SSAPage as well.
public CustomLinkToNewPage(String id, Class<T> name)
Then I passed in the .class reference to the object, and created a new instance of the object using reflection.. then set that instance to Page, and passed it to setResponsePage in my onClick. Worked nicely, as I couldn't figure out how to do Nicktar's way. So this an alternative in case anyone else runs into this issue.
By default, grails seems to return <class name>:<id> for toString() of an Java domain object. That's not at all what I want of course, so I tried to #Override
the toString() to return what I want. When I tried grails generate-all Tagtype, I got the following error:
java.lang.LinkageError: loader constraint violation: loader (instance of <bootloader>) previously initiated loading for a differen
t type with name "org/w3c/dom/NamedNodeMap"
My code is below. Any help would be greatly appreciated.
#Entity
#Table(name = "tagtype", catalog = "tigger")
#SuppressWarnings("serial")
public class Tagtype implements Serializable {
/**
* Attribute id.
*/
private Integer id;
/**
* Attribute tagtype.
*/
private String tagtype;
/**
* Attribute regexpression
*/
private Regexpression regexpression;
. . .
#Override public String toString() {
StringBuilder result = new StringBuilder();
result.append(this.tagtype);
return result.toString();
}
}
I've overriden toString() in Grails domain classes without any problems, so that can't be the reason. This blog suggests it could be a result of name collisions, either temporary (have you tried running "grails clean"?) or perhaps your class name Tagtype collides with some grails internals.
Another thing you could try is using different versions of Grails, especially the latest 1.1.1 if you aren't already using that. This ML post describes an identical error message that was apparently version dependant.