How to Call Other Class Values

I am creating a vehicle control, and in it I have a Fuel register that has description and value, and another cadastre of Supplies. In my supply register has a autoComplete of Fuel. The problem starts here, when I select the fuel I need to call the cost value that is entered in this fuel.

Example: I selected Diesel.

TOTAL = Valor * LitrosAbastecidos.

However, the Valor variable is within the Fuel class. Would anyone have a simple way to solve this?

Note: System made in Java, Hibernate, JSF

Call the Combustible

<p:autoComplete id="combustivel" value="#{abastecimentoControle.abastecimento.combustivel}" completeMethod="#{combustivelControle.listaFiltrando}"
                                       converter="#{combustivelControle.combustivelConverter}"
                                       var="c"
                                       disabled="true"
                                       itemValue="#{c}"
                                       itemLabel="#{c.descricao}"/>

My Filtering List

public List<Combustivel> listaFiltrando(String parte){
    System.out.println("Parte: "+parte);
    return combustivelFacade.listaFiltrando(parte);
}