选择下拉列表元素后，我想在JSF中启用inputtext

Question

选择下拉列表元素后，我想在JSF中启用输入文本。

<h:selectOneMenu value="#{country.val}" valueChangeListener="#{country.comboChange}">

    <f:selectItems id="musti" value="#{country.authenticationAlgoritms}"/>
    <a4j:support event="onchange" ajaxSingle="true" reRender="musti3"/>
</h:selectOneMenu>

<h:inputText id="musti3" disabled="#{not(country.val == 'SHA256')}"/>

@ManagedBean(name="country")
@SessionScoped
public class UserBean implements Serializable{

    private static final long serialVersionUID = 1L;
    private String val;
    private boolean booleanValue;


    public void setVal(String val) {
        this.val = val;
    }
    public String getVal(){
        return val;
    }
    public boolean isBooleanValue() {
        return booleanValue;
    }

    public void setBooleanValue(boolean booleanValue) {
        this.booleanValue = booleanValue;
    }
    public void comboChange(ValueChangeEvent e){

        String s = e.getNewValue().toString();
        if(s.equals("SHA256")){
            setVal("SHA256");
        }
        FacesContext.getCurrentInstance().renderResponse();
    }
    public ArrayList<String> getAuthenticationAlgoritms() {

        ArrayList<String> arr = new ArrayList();
        arr.add("NONE");
        arr.add("SHA256");
        return arr;
    }
}