com.ocs.dynamo.ui.provider.PagingDataProvider Maven / Gradle / Ivy

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/*
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
 */
package com.ocs.dynamo.ui.provider;

import java.io.Serializable;
import java.util.stream.Stream;

import com.ocs.dynamo.dao.FetchJoinInformation;
import com.ocs.dynamo.dao.SortOrders;
import com.ocs.dynamo.domain.AbstractEntity;
import com.ocs.dynamo.domain.model.EntityModel;
import com.ocs.dynamo.filter.Filter;
import com.ocs.dynamo.filter.FilterConverter;
import com.ocs.dynamo.service.BaseService;
import com.ocs.dynamo.ui.utils.VaadinUtils;
import com.vaadin.flow.data.provider.Query;
import com.vaadin.flow.function.SerializablePredicate;

/**
 * 
 * @author Bas Rutten
 *
 * @param  the type of the ID of the entity
 * @param  the type of the entity
 */
public class PagingDataProvider> extends BaseDataProvider {

    private static final long serialVersionUID = 8238057223431007376L;

    /**
     * The number of items in the provider. This is set by doing a count query
     */
    private int size;

    /**
     * Whether iteration through the data set is required
     */
    private boolean iterationRequired;

    /**
     * Constructor
     * 
     * @param service     the service
     * @param entityModel the entity model
     * @param joins       the joins to use when querying
     */
    public PagingDataProvider(BaseService service, EntityModel entityModel, boolean iterationRequired,
            FetchJoinInformation... joins) {
        super(service, entityModel, joins);
        this.iterationRequired = iterationRequired;
    }

    @Override
    public Stream fetch(Query> query) {
        FilterConverter converter = getFilterConverter();
        int offset = query.getOffset();
        int page = offset / query.getLimit();
        int pageSize = getMaxResults() != null && offset + query.getLimit() > getMaxResults() ? getMaxResults() - offset : query.getLimit();
        SortOrders sortOrders = createSortOrder(query);
        Filter filter = converter.convert(query.getFilter().orElse(null));
        return getService().fetch(filter, page, pageSize, sortOrders, getJoins()).stream();
    }

    @Override
    public int getSize() {
        return size;
    }

    @Override
    public int size(Query> query) {
        FilterConverter converter = new FilterConverter<>(getEntityModel());
        Filter filter = converter.convert(query.getFilter().orElse(null));

        size = (int) getService().count(filter, false);
        if (getMaxResults() != null && size >= getMaxResults()) {
            showNotification(getMessageService().getMessage("ocs.too.many.results", VaadinUtils.getLocale(), getMaxResults()));
            size = getMaxResults();
        }

        // retrieve IDs as well (needed for iteration)
        if (iterationRequired) {
            SortOrders so = createSortOrder(query);
            ids = getService().findIds(filter, getMaxResults(), so.toArray());
        }

        if (getAfterCountCompleted() != null) {
            getAfterCountCompleted().accept(size);
        }
        return size;
    }

    @Override
    public ID firstItemId() {
        return ids == null ? null : ids.get(0);
    }

    @Override
    public int indexOf(ID id) {
        return ids == null ? -1 : ids.indexOf(id);
    }

}