Linha selecionada na DataTable carregar em um Dialog

<h:form>                          
            <h:outputText value="Contagem: "/>            
            <h:inputText value="#{contag_almController.numcnt}"/> &nbsp;            
            <p:commandButton  value="Pesquisar" actionListener="#{contag_almController.procurarNumContagPorNum()}" update="contag_alm" />
            <br> </br>            
            <p:dataTable value="#{contag_almController.list}" var="Contag_alm" id="contag_alm" paginator="true" rows="20">
                <p:ajax event="rowSelect" update="contag_alm" />
                <p:column headerText="Contagem" style="width: 75px">
                    <h:outputText value="#{Contag_alm.numcnt}"/>
                </p:column>

                <p:column headerText="Sequencia" style="width: 75px">
                    <h:outputText value="#{Contag_alm.seqcnt}"/>
                </p:column>

                <p:column headerText="Produto" style="width: 300px">                    
                    <h:outputText value="#{Contag_alm.despro}"/>                    
                </p:column>

                <p:column headerText="Cor" style="width: 200px">                    
                    <h:outputText value="#{Contag_alm.desder}"/>                    
                </p:column>
                <p:column headerText="Qtd." style="width: 75px">                    
                    <h:outputText value="#{Contag_alm.qtdcnt}"/>                    
                </p:column>
                <p:column style="width: 30px">  
                    <p:commandButton oncomplete="PF('contag_almDialog').show()" title="View" immediate="true">     
                        <f:setPropertyActionListener target="#{contag_almController.contag_alm}"
                             value="#{contag_alm}"/>
                    </p:commandButton>
                </p:column>
            </p:dataTable>  
            <br></br>   

            <p:dialog widgetVar="contag_almDialog" 
                      resizable="false" 
                      header="Qtd" 
                      height="100" 
                      width="500" 
                      showEffect="explode"
                      hideEffect="explode"   
                      modal="true" 
                      dynamic="true"
                      style="height:30px; font-size: 13px; font-family: sans-serif" >   
                <h:outputText value="#{contag_almController.contag_alm.numcnt}"/>                 
            </p:dialog>

@ManagedBean
@ViewScoped
public class Contag_almController {

    private Contag_alm contag_alm;
    private DataModel listaContag_alm;

    List lista;
    int numcnt;

    public int getNumcnt() {
        return numcnt;
    }

    public void setNumcnt(int numcnt) {
        this.numcnt = numcnt;
    }

    public Contag_alm getContag_alm() {
        if (this.contag_alm == null) {
            this.contag_alm = new Contag_alm();
        }
        return contag_alm;
    }

    public void setContag_alm(Contag_alm contag_alm) {
        this.contag_alm = contag_alm;
    }

    public List<Contag_alm> listaContag_alm() {
        List<Contag_alm> lista;
        lista = new Contag_almDao().list();
        return lista;
    }

    public DataModel getListaContag_alm() {
        List<Contag_alm> lista = new Contag_almDao().list();
        listaContag_alm = new ListDataModel(lista);
        return listaContag_alm;
    }

    public void prepararAlterarContag_alm(ActionEvent actionEvent) {
        contag_alm = (Contag_alm) (listaContag_alm.getRowData());
    }

    public void atualizarContag_alm() {
        InterfaceConag_alm dao = new Contag_almDao();
        dao.atualizar(contag_alm);
    }
  
    public List<Contag_alm> getList() {
        return lista;
    }

    public List procurarNumContagPorNum() {
        Session ss = HibernateUtil.getSessionFactory().getCurrentSession();
        ss.beginTransaction();
        Query q = ss.createQuery("from contag_alm where numcnt = :numcnt");
        q.setParameter("numcnt", numcnt);
        lista = q.list();
        ss.getTransaction().commit();
        return lista;
    }
}

public class Contag_almDao implements InterfaceConag_alm {   
    @Override
    public List<Contag_alm> list() {
        Session ss = HibernateUtil.getSessionFactory().getCurrentSession();
        ss.beginTransaction();
        List lista = ss.createQuery("From contag_alm").list();
        ss.getTransaction().commit();
        return lista;
    }   

    @Override
    public void atualizar(Contag_alm contag_alm) {
        Session ss = HibernateUtil.getSessionFactory().getCurrentSession();
        ss.beginTransaction();
        ss.update(contag_alm);
        ss.getTransaction().commit();
    }
}

@Entity(name = "contag_alm")
public class Contag_alm implements Serializable{
    
    @Id
    @GeneratedValue
    int numcnt, seqcnt;
    private String sitcnt, codpro, despro, codder, desder, qtdcnt;

    public int getSeqcnt() {
        return seqcnt;
    }

    public void setSeqcnt(int seqcnt) {
        this.seqcnt = seqcnt;
    }

    public int getNumcnt() {
        return numcnt;
    }

    public void setNumcnt(int numcnt) {
        this.numcnt = numcnt;
    }    

    public String getSitcnt() {
        return sitcnt;
    }

    public void setSitcnt(String sitcnt) {
        this.sitcnt = sitcnt;
    }

    public String getCodpro() {
        return codpro;
    }

    public void setCodpro(String codpro) {
        this.codpro = codpro;
    }

    public String getDespro() {
        return despro;
    }

    public void setDespro(String despro) {
        this.despro = despro;
    }

    public String getCodder() {
        return codder;
    }

    public void setCodder(String codder) {
        this.codder = codder;
    }

    public String getDesder() {
        return desder;
    }

    public void setDesder(String desder) {
        this.desder = desder;
    }

    public String getQtdcnt() {
        return qtdcnt;
    }

    public void setQtdcnt(String qtdcnt) {
        this.qtdcnt = qtdcnt;
    }    
}