EntityListProvider.java

package org.aplikator.server.descriptor;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.aplikator.client.shared.data.ListItem;
import org.aplikator.server.data.Context;
import org.aplikator.server.data.QueryBuilder;
import org.aplikator.server.data.Record;

/**
 * Implementation of the {@link ListProvider} interface dynamically backed by an Entity
 */
public class EntityListProvider extends ListProvider.Default {
    private static final String DEFAULT_LANG = "default";
    private View view;
    private Property valueProperty;
    private Map<String, Property> localeProperties = new HashMap<String, Property>();
    private Map<String, List<ListItem>> listValues = new HashMap<String, List<ListItem>>();
    ;


    /**
     * @param listName      unique identifier of the list
     * @param view          {@link View} for the {@link Entity} that provides the values for this list.
     *                      The View must contain all Properties used as {@link #valueProperty}
     *                      and {@link #addLanguageProperty(String, Property)}
     * @param valueProperty The property (declared in the {@link #view} that contains the values
     *                      that should be returned by the ListItems {@link ListItem#getValue()} method
     */
    public EntityListProvider(String listName, View view, Property valueProperty) {
        this(listName, view, valueProperty, valueProperty);
    }

    public EntityListProvider(String listName, View view, Property valueProperty, Property defaultLocaleProperty) {
        super(listName);
        this.view = view;
        this.valueProperty = valueProperty;
        addLanguageProperty(DEFAULT_LANG, defaultLocaleProperty);
    }

    /**
     * Calling this method tells the EntityListProvider which property from the backing View should provide ListItem names
     * (localized labels) for the given locale
     *
     * @param lang     language code of the locale
     * @param property Property containing the names for the given locale
     * @return this object for fluent method call chaining
     */
    public EntityListProvider addLanguageProperty(String lang, Property property) {
        localeProperties.put(lang, property);
        listValues.put(lang, new ArrayList<ListItem>());
        return this;
    }

    /**
     * @param ctx
     */
    @SuppressWarnings("unchecked")
    public void refreshListValues(Context ctx) {
        for (String loc : listValues.keySet()) {
            listValues.get(loc).clear();
        }
        QueryBuilder qb = ctx.getRecords(view);
        if (view.getQueryDescriptors().size() > 0) {
            String queryID = view.getQueryDescriptors().get(0).getId();
            qb.withQuery(view.getQueryDescriptor(queryID).getQueryExpression(null, ctx));
        }
        if (view.getSortDescriptors().size() > 0) {
            qb.withSort(view.getSortDescriptors().get(0).getItems().toArray(new SortItem[]{}));
        }
        List<Record> records = qb.list();
        for (Record record : records) {
            for (String loc : listValues.keySet()) {
                ListItem listItem = new ListItem.Default(record.getValue(valueProperty), record.getStringValue(localeProperties.get(loc), ctx));
                listValues.get(loc).add(listItem);
            }
        }
    }

    @Override
    public List<ListItem> getListValues(Context ctx) {
        String lang = ctx.getUserLocale().getLanguage();

        List<ListItem> list = listValues.get(lang);
        if (list == null) {
            list = listValues.get(DEFAULT_LANG);
            lang = DEFAULT_LANG;
        }
        if (list.size() == 0) {
            refreshListValues(ctx);
            list = listValues.get(lang);
        }
        if (sortByName) {
            Collections.sort(list, new ListItem.Comparator());
        }
        return list;
    }
}