<p:commandButtonrendered="#{empty slot.place and empty slot.used}"value="#{i18n['placeslot.lockSlot']}"actionListener="#{placeGroupView.lockSlot}"update="placeslots"/>
<p:commandButtonrendered="#{empty slot.place and empty slot.used}"
<p:commandButtonrendered="#{empty slot.place and not empty slot.used}"value="#{i18n['placeslot.releaseSlot']}"actionListener="#{placeGroupView.releaseSlot}"update="placeslots"/>