How to pass a parameter along with h:commandButton

Question

One of the most common approaches to change locale in JSF+Seam - with :

Answer 1

Either pass as method argument (only if your environment supports EL 2.2),

<h:commandButton value="English" action="#{localeSelector.change('en')}" />
<h:commandButton value="Deutsch" action="#{localeSelector.change('de')}" />
<h:commandButton value="Français" action="#{localeSelector.change('fr')}" />

with

public void change(String language) {
    locale = new Locale(language);
    // ...
}

---

Or use <f:setPropertyActionListener>

<h:commandButton value="English" action="#{localeSelector.change}">
    <f:setPropertyActionListener target="#{localeSelector.language}" value="en" />
</h:commandButton>
<h:commandButton value="Deutsch" action="#{localeSelector.change}">
    <f:setPropertyActionListener target="#{localeSelector.language}" value="de" />
</h:commandButton>
<h:commandButton value="Français" action="#{localeSelector.change}">
    <f:setPropertyActionListener target="#{localeSelector.language}" value="fr" />
</h:commandButton>

with

private String language;

public void change() {
    locale = new Locale(language);
    // ...
}

---

Or use <f:param>

<h:commandButton value="English" action="#{localeSelector.change}">
    <f:param name="language" value="en" />
</h:commandButton>
<h:commandButton value="Deutsch" action="#{localeSelector.change}">
    <f:param name="language" value="de" />
</h:commandButton>
<h:commandButton value="Français" action="#{localeSelector.change}">
    <f:param name="language" value="fr" />
</h:commandButton>

with

public void change() {
    locale = new Locale(FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap().get("language"));
    // ...
}

(you can also let JSF automatically set it by a @ManagedProperty("#{param.language}"), but this requires the bean to be request scoped, or a <f:viewParam>, see also ViewParam vs @ManagedProperty(value = "#{param.id}"))

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Enough ways to pass a parameter from view to controller. Take your pick. The <h:inputHidden> serves in JSF context a somewhat different purpose and it can only be manipulated by JavaScript in the onclick which is ugly.