CODEWITHSUNDEEP
jsfparameterseljavabeans
geeehhdaa
geeehhdaa

Reputation: 822

JSF: Bean method call with parameter

I can't get method calls with parameters to work in JSF 2.0 (MyFaces) and Tomcat 6.

This is how I try it:

<f:selectItems var="item" value="#{bla.someList} itemValue="#{item.value1}" itemLabel="#{item.value2}"> <f:param name="param1" value="0" /> </f:selectItems>

I can't define the method like this, right? And why not?

getSomeList(int a)

So this is what I tried:

getSomeList() {
Integer a = Integer.parseInt(FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap().get("param1")); 
return doSomething(a);
}

And this is what I get:

java.lang.NumberFormatException: null
java.lang.Integer.parseInt(Integer.java:417)

I would be very grateful if someone helped me out. Thanks!

UPDATE: Ah, it worked with #{bla.getSomeList(0)}!

Upvotes: 2

Views: 10119

Answers (2)

BalusC
BalusC

Reputation: 1108557

I can't define the method like this, right?

getSomeList(int a)

No.

And why not?

Because you're using old Tomcat 6 which doesn't support EL 2.2 where this feature was introduced.

And this is what I get:

java.lang.NumberFormatException: null
java.lang.Integer.parseInt(Integer.java:417)

Because there it is null. The <f:param> works in links/buttons only, not on plain components.

In order to get method calls in EL to work, you need to upgrade to a Servlet 3.0 / EL 2.2 capable container like Tomcat 7, or to replace Tomcat 6's default EL 2.1 implementation by one which supports parameterized method calls. For detail see this answer. Once done that, you can use

<f:selectItems value="#{bla.getSomeList(0)}" ... />

An alternative is to replace List by Map, which can be a custom implementation which does (lazy) loading on get() method.

public Map<String, List<Something>> getSomeMap() {
    return someCustomLazyLoadingMap;
}

with

<f:selectItems value="#{bla.someMap.keyName}" ... />

Upvotes: 5

aseychell
aseychell

Reputation: 1804

Try using

<f:selectItems var="item" value="#{bla.someList(0)} itemValue="#{item.value1}" itemLabel="#{item.value2}"/>

This works for some implementations of JSF.

Upvotes: 0

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