JSF Lookup SelectItem cheat sheet

LookupConverterTemplate.java

package us.ne.state.nsc.npacs.lookupbean;

import org.springframework.data.jpa.repository.JpaRepository;
import us.ne.state.nsc.npacs.lookup.NpacsLookup;

import javax.faces.application.FacesMessage;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.convert.Converter;
import javax.faces.convert.ConverterException;

import static org.apache.commons.lang.StringUtils.isNotEmpty;

public abstract class LookupConverterTemplate implements Converter {

    /**
     * subclass should provide repo, probably as a ManagedProperty
     */
    protected JpaRepository<? extends NpacsLookup, Integer> repo;

    public void setRepo(JpaRepository<? extends NpacsLookup, Integer> repo) {
        this.repo = repo;
    }

    @Override
    public Object getAsObject(FacesContext facesContext, UIComponent uiComponent, String value) {

        if (isNotEmpty(value)) {

            try {
                int id = Integer.valueOf(value);
                return repo.findOne(id);

            } catch (NumberFormatException e) {
                throw new ConverterException(new FacesMessage(FacesMessage.SEVERITY_ERROR, "Conversion Error", "Not a valid Lookup."));
            }
        } else {
            return null;
        }
    }

    @Override
    public String getAsString(FacesContext facesContext, UIComponent uiComponent, Object object) {

        if (object != null && NpacsLookup.class.isAssignableFrom(object.getClass())) {
            NpacsLookup lookup = (NpacsLookup) object;

            Object id = lookup.getLookupCd();
            if(id == null)
                id = lookup.getStrLookupCd();

            return String.valueOf(id);
        } else {
            return null;
        }
    }
}

NpacsPageBean.java

    protected List<SelectItem> getSelectItemObjectList(List<? extends NpacsLookup> lookupList) {
        return getSelectItemObjectList(lookupList, true, false, true, true, true);
    }

    protected List<SelectItem> getSelectItemList(List<? extends NpacsLookup> lookupList, boolean toIncludeBlankEntry,
            boolean toAbbreviateDescription, boolean activeOnly, boolean toSort, boolean useObjects) {

        List<SelectItem> result = new ArrayList<>();

        for (NpacsLookup lookup : lookupList) {

            if (activeOnly && !lookup.getActive())
                continue;
            if(lookup.getLookupCd() == null && lookup.getStrLookupCd() == null)
                continue;

            boolean isIntegerLookupCd = lookup.getLookupCd() != null;

            if (toIncludeBlankEntry) {
                toIncludeBlankEntry = false;

                Object emptyValue;

                if (useObjects || lookup instanceof AssessmentLookup) {
                    emptyValue = null;
                } else if (isIntegerLookupCd ) {
                    emptyValue = 0;
                } else {
                    emptyValue = "";
                }
                result.add(new SelectItem(emptyValue, ""));
            }

            String description = lookup.getDescription();

            if (toAbbreviateDescription) {
                description = StringUtils.abbreviate(description, 40);
            }

            Object lookupCd = isIntegerLookupCd ? lookup.getLookupCd() : lookup.getStrLookupCd();

            Object selectItemValue = useObjects ? lookup : lookupCd;

            result.add(new SelectItem(selectItemValue, description));
        }

        if (toSort) {
            sort(result, "label", true);
        }

        return result;
    }

Victim.java

@Entity
@Table(name = "victim")
public class Victim extends Npacs {
  
	private VictimRaceEthnicityLookup victimRaceEthnicityLookup;
  
	@ManyToOne(targetEntity = VictimRaceEthnicityLookup.class, fetch = FetchType.LAZY)
	@JoinColumn(name = "fk_Victim_Race_Ethnicity_Cd")
	public VictimRaceEthnicityLookup getVictimRaceEthnicityLookup() {
		return victimRaceEthnicityLookup;
	}

	public void setVictimRaceEthnicityLookup(VictimRaceEthnicityLookup victimRaceEthnicityLookup) {
		this.victimRaceEthnicityLookup = victimRaceEthnicityLookup;
	}
}

VictimBean.java

@ManagedBean
@SessionScoped
public class VictimBean extends NpacsPageBean {
    
    @ManagedProperty(value = "#{lookupService}")
    private ILookupService lookupService;
    
    private Victim victim;
    private List<SelectItem> victimRaceEthnicityList;
    
    public void buildSelectItems() {
        if(victimRaceEthnicityList == null) {
            victimRaceEthnicityList = getSelectItemObjectList(lookupService.getVictimRaceEthnicityLookupList());
        }
    }
    
    public List<SelectItem> getVictimRaceEthnicityList() {
        return victimRaceEthnicityList;
    }

    public void setVictimRaceEthnicityList(List<SelectItem> victimRaceEthnicityList) {
        this.victimRaceEthnicityList = victimRaceEthnicityList;
    }
    
    public Victim getVictim() {
        return victim;
    }
    
    public void setVictim(Victim victim) {
        this.victim = victim;
    }
}

victimEntry.xhtml

...

<!-- Notice that the value attribute is a business object type, not an Integer (ID) 
     type. This REQUIRES a converter.  It also means we don't have to worry about 
     keeping an ID in synch with a @Transient description anymore.
     
     Tried adding separate getter/setters to Victim, one for the Lookup object and
     one for its foreign key value, but Hibernate REFUSES to update both in the same
     transaction. 
     
     Notice that the converter attribute uses #{} syntax instead of the typical ""
     because this converter is a ManagedBean (necessary for ManagedProperty injection)
-->

<h:panelGroup rendered="#{victimBean.displayVictimRaceEthnicity}">
    <h:selectOneMenu id="victimRaceEthnicity" required="true" requiredMessage="#{npacsMessages.requiredEntry}"
                     value="#{victimBean.victim.victimRaceEthnicityLookup}"
                     converter="#{victimRaceEthnicityConverter}">
        <f:selectItems id="victimRaceEthnicityList" value="#{victimBean.victimRaceEthnicityList}"/>
    </h:selectOneMenu>&nbsp; <h:message for="victimRaceEthnicity" styleClass="errorMessage"/>
</h:panelGroup>

...

VictimRaceEthnicityConverter.java

package us.ne.state.nsc.npacs.lookupbean;

import us.ne.state.nsc.npacs.court.VictimRaceEthnicityLookupRepo;

import javax.faces.bean.ManagedBean;
import javax.faces.bean.ManagedProperty;
import javax.faces.bean.SessionScoped;

@ManagedBean(name = "victimRaceEthnicityConverter")
@SessionScoped
public class VictimRaceEthnicityConverter extends LookupConverterTemplate {

    @ManagedProperty(value = "#{victimRaceEthnicityLookupRepo}")
    private VictimRaceEthnicityLookupRepo repo;
}

VictimRaceEthnicityLookup.java

@Entity
public class VictimRaceEthnicityLookup extends NpacsLookup {

    private static final long serialVersionUID = 1L;

    public VictimRaceEthnicityLookup() {
        super();
    }

    public VictimRaceEthnicityLookup(Integer lookupCd, String description) {
        super(lookupCd, description);
    }

    @Id
    @Column(name = "pk_Victim_Race_Ethnicity_Cd")
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Override
    public Integer getLookupCd() {
        return lookupCd;
    }

    @Column(name = "victim_Race_Ethnicity_Descr")
    public String getDescription() {
        return description;
    }

  // MUST OVERRIDE EQUALS AND HASHCODE so that JSF can secretly track the list in the background (security measure)
    @Override
    public boolean equals(Object object) {
        return (object instanceof VictimRaceEthnicityLookup) && (lookupCd != null)
                ? lookupCd.equals(((VictimRaceEthnicityLookup) object).lookupCd)
                : (object == this);
    }

    @Override
    public int hashCode() {
        return (lookupCd != null)
                ? (VictimRaceEthnicityLookup.class.hashCode() + lookupCd.hashCode())
                : super.hashCode();
    }
}