Is @Produces more efficient that a getter in an EL expression

问题

I'm wondering which of those two code snippets is more efficient.

---

First one

In userSearch.xhtml :

<rich:dataTable
    var="user"
    value="#{userSearchResultList}"
    rendered="#{not empty userSearchResultList}">
...
</rich:dataTable>

In UserSearchAction.java :

@Produces @RequestScoped
@Named("userSearchResultList")
public List<User> getResultList() {
    return resultList;
}

---

Second one

In userSearch.xhtml :

<rich:dataTable
    var="user"
    value="#{userSearchAction.resultList}"
    rendered="#{not empty userSearchAction.resultList}">
...
</rich:dataTable>

In UserSearchAction.java :

public List<User> getResultList() {
    return resultList;
}

---

In both solutions, my resultList variable is filled by a method UserSearchAction.search().

I'm using JBoss 7.0.2.Final and RichFaces 4.1.0.Final.

More generally, I wanted to know if it's better to write producers than to call sub-properties of some classes in JSF files.

回答1:

That depends on how your producer scopes what is being produced. If it's dependent scoped (meaning you don't have a scope on it, nor on the containing class) it ends up being the same, possibly less depending what it is you are having to do inside that method.

In your example it should be more efficient because that producer method should only be called once (per request).

来源：https://stackoverflow.com/questions/8592583/is-produces-more-efficient-that-a-getter-in-an-el-expression