<h:form>
    <br/>
    <p:outputLabel for="botao-iniciar">Iniciar transferências:</p:outputLabel>
    <p:commandButton id="botao-iniciar" onclick="PF('pbAjax-1').start()"
    widgetVar="startButton" value="Iniciar" />
    <br/><br/>
    <p:separator />

    <ui:repeat var="transf" value="#{transferenciaStatusMB.listaTransferencia}">
        <h:panelGrid style="width:100%">
            <p:outputLabel>Transferência ID: #{transf.id}</p:outputLabel>

            <p:progressBar widgetVar="pbAjax-#{transf.id}" ajax="true"
            value="#{transferenciaStatusMB.getProgresso(transf)}"
            labelTemplate="{value}%" global="false" interval="1000" >
                <p:ajax event="complete"
                listener="#{transferenciaStatusMB.onComplete(transf)}" />
            </p:progressBar>

            <p:commandButton widgetVar="cancelButton-#{transf.id}" value="Cancelar"
            actionListener="#{transferenciaStatusMB.cancelar(transf)}"
            oncomplete="PF('cancelButton-#{transf.id}').disable();" >
            </p:commandButton>

            <p:separator />
        </h:panelGrid>
    </ui:repeat>
</h:form>

// Simulate task (based on the Primefaces' showcase example):
public Integer getProgresso(Transferencia transferencia) {
    if(transferencia.getProgresso() == null) {
        transferencia.setProgresso(0);
    } else {
           System.out.printf("Progress Transference ID %d: %d.n", transferencia.getId(), transferencia.getProgresso());

        if(transferencia.getProgresso() < 100){
            transferencia.setProgresso(
                transferencia.getProgresso() + (int)(Math.random() * 35));

            if(transferencia.getProgresso() > 100) {
                transferencia.setProgresso(100);
            }
        }

        try {
            Thread.sleep(2000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    return transferencia.getProgresso();
}

// Cancel a task:
public void cancelar(Transferencia transferencia) {
    transferencia.setProgresso(null);
    System.out.println("Transferencia ID " + transferencia.getId() +" CANCELADA!");
}

// After a task is completed:
public void onComplete(Transferencia transferencia) {
    System.out.println("Transferencia ID " + transferencia.getId() +" FINALIZADA!");
}