Checking for string length in Expression language
Solution 1
This means that your environment doesn't support the new EL 2.2 feature of invoking non-getter methods with parentheses.
Your best bet is using JSTL's fn:length() instead.
<html ... xmlns:fn="http://java.sun.com/jsp/jstl/functions">
...
rendered="#{fn:length(tabbedToolbarBean.editor.selectedQuery) gt 0}"
Alternatively, just use empty keyword in EL. The difference is that it also checks nullness.
rendered="#{not empty tabbedToolbarBean.editor.selectedQuery}"
See also:
Solution 2
Try the JSTL fn:length() function:
rendered="#{fn:length(tabbedToolbarBean.editor.selectedQuery) gt 0}"
Inquisitive
Updated on June 30, 2022Comments
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Inquisitive almost 2 years
I am using JSF and want to have a component that should be rendered only when the value of a String in the associated managed bean is greater than zero. I am doing this :
rendered="#{tabbedToolbarBean.editor.selectedQuery.length() gt 0}"Additionally the signature of getter for
selectedQueryispublic String getSelectedQuery(){}. I get the following error with the latest version of weblogic server.Error: Function length has an invalid prefix or uses the default namespace which is not defined. Correct the prefix or in a jsp document, put the function inside a tag that defines the tag library namespace
What am I missing?Not getting much help after googling.