Possible to specify access to isAttribute vs getAttribute in JSP EL?

Question

Our Topic object has BOTH isChannel and getChannel public methods. The object graph is too complex to change this. Channel has an Integer type.

We are migrating from one application server to Tomcat. When using this expression ${topic.channel.type}, in JSPs our current app server finds the getChannel method. However, Tomcat finds the isChannel method and we get errors since the return type is a Boolean, not a Channel. Is there a way to tell Tomcat to prefer getters over boolean public methods?

For now I'm just going to write a helper function or expose a new method, but I have a feeling I'm going to come across this quite a bit during the migration.

Answer 1

Unfortunately, you can't force a method call like that.

I have checked the Javabeans and EL specifications, but nowhere is specified what the preferred method is when both isXXX() and getXXX() methods are present. However, I do agree that it makes more sense to prefer the getXXX() one in this particular case. This should also be programmatically possible. I think it's worth the effort to report this as an issue against the Tomcat EL implementation.

Answer 2

In theory, this should be more of a JavaBeans issue than an EL implementation issue. One thing you might try is to find out how the java.beans.Introspector views your Topic class. One way to do that would be to run this code I wrote a while back for the Struts wiki. Depending on the complexity of your class, it might make sense to create an explicit java.beans.BeanInfo class to force the channel property to always be exposed as an Integer.