o

o:methodParam is a tag handler that can be used to pass a method expression into a Facelets tag.

By default this is not possible, and the expression that's intended to be a method expression will be created and made available as a value expression. This handler should be placed inside a Facelets tag as follows:

<ui:composition
    xmlns="http://www.w3.org/1999/xhtml"
    xmlns:ui="http://xmlns.jcp.org/jsf/facelets"
    xmlns:h="http://xmlns.jcp.org/jsf/html"
    xmlns:o="http://omnifaces.org/ui"
>
    <o:methodParam name="method" value="#{action}"/>

    <h:commandButton value="test" action="#{method}" />

</ui:composition>
                

Assuming the above is a tag called actionmethod in the namespace test, a method can be passed into it as follows:

<test:actionmethod action="#{methodParamBean.doAction}" />
                

In case a method with no parameters is passed that is to be used as an action listener with no parameters, then the component using this method unfortunely has to be wrapped by a component that puts the method in request scoped (with nested visibility), e.g. by using ui:repeat as follows:

<ui:repeat var="method" value="#{method}">
    <h:commandButton value="test" actionListener="#{method}" />
</ui:repeat>
                

Using modern EL implementations, this is not needed in case the EL expression references the method using explicit parenthesis, e.g. #{methodParamBean.doAction()}