Application: gvSIG desktop

import java.util.Objects;

import org.gvsig.expressionevaluator.MutableSymbolTable;

import org.gvsig.fmap.dal.DALLocator;

import org.gvsig.fmap.dal.feature.Feature;

import org.gvsig.fmap.dal.feature.ForeingKey;

import static org.gvsig.fmap.dal.feature.ForeingKey.MAX_AVAILABLE_VALUES;

import org.gvsig.tools.dynobject.DynObjectValueItem;

    private Map<String,DynObjectValueItem[]> availableValues = null;

    @Override

    public DynObjectValueItem[] getAvailableValues(FeatureStore myStore, FeatureAttributeDescriptor descriptor) {

        String keyName = myStore.getFullName() + ":columnName=" + descriptor.getName();

        if( this.availableValues==null ) {

            this.availableValues = new HashMap<>();

        }

        DynObjectValueItem[] values = this.availableValues.get(keyName);

        if( values != null ) {

            return values;

        }

        if( !descriptor.isForeingKey() ) {

            return null;

        }

        ForeingKey foreingKey = descriptor.getForeingKey();

        try {

            StoresRepository theStoresRepository;

            FeatureStore store = descriptor.getStore();

            if (store == null) {

                theStoresRepository = DALLocator.getDataManager().getStoresRepository();

            } else {

                theStoresRepository = store.getStoresRepository();

            }

            FeatureStore foreingStore = (FeatureStore) theStoresRepository.getStore(

                foreingKey.getTableName()

            );

            Expression labelExpression = foreingKey.getLabelExpression(null);

            String codeName = foreingKey.getCodeName();

            FeatureSymbolTable featureSymbolTable = this.createFeatureSymbolTable();

            MutableSymbolTable symbolTable = featureSymbolTable.createParent();

            int count = (int) foreingStore.getFeatureCount();

            values = new DynObjectValueItem[Math.min(count, MAX_AVAILABLE_VALUES)];

            int n = 0;

            for (Feature feature : foreingStore.getFeatureSet()) {

                Object code = feature.get(codeName);

                Object value;

                if (labelExpression == null) {

                    value = code;

                } else {

                    featureSymbolTable.setFeature(feature);

                    value = labelExpression.execute(symbolTable);

                }

                values[n++] = new DynObjectValueItem(code, Objects.toString(value, Objects.toString(code, "##ERROR##")));

                if( n>=MAX_AVAILABLE_VALUES ) {

                    break;

                }

            }

            this.availableValues.put(keyName, values);

            return values;

        } catch (Exception ex) {

            LOGGER.warn("Can't get available values for field '"+myStore.getName()+"."+descriptor.getName()+"' from table '" + foreingKey.getTableName() + "'.", ex);

        }

        return null;

    }