org.eclipse.jnosql.artemis.column.ColumnPage Maven / Gradle / Ivy

/*
 *  Copyright (c) 2019 Otávio Santana and others
 *   All rights reserved. This program and the accompanying materials
 *   are made available under the terms of the Eclipse Public License v1.0
 *   and Apache License v2.0 which accompanies this distribution.
 *   The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 *   and the Apache License v2.0 is available at http://www.opensource.org/licenses/apache2.0.php.
 *
 *   You may elect to redistribute this code under either of these licenses.
 *
 *   Contributors:
 *
 *   Otavio Santana
 */
package org.eclipse.jnosql.artemis.column;

import jakarta.nosql.mapping.Page;
import jakarta.nosql.mapping.Pagination;
import jakarta.nosql.mapping.column.ColumnQueryPagination;
import jakarta.nosql.mapping.column.ColumnTemplate;

import java.util.Collection;
import java.util.List;
import java.util.Objects;
import java.util.function.Supplier;
import java.util.stream.Collectors;
import java.util.stream.Stream;

/**
 * An implementation of {@link Page} to Column.
 *
 * @param  the entity type
 */
final class ColumnPage implements Page {

    private final ColumnTemplate template;

    private final Stream entities;

    private final ColumnQueryPagination query;

    private List entitiesCache;

    ColumnPage(ColumnTemplate template, Stream entities, ColumnQueryPagination query) {
        this.template = template;
        this.entities = entities;
        this.query = query;
    }

    @Override
    public Pagination getPagination() {
        return query.getPagination();
    }

    @Override
    public Page next() {
        return template.select(query.next());
    }

    @Override
    public Stream getContent() {
        return getEntities();
    }


    @Override
    public > C getContent(Supplier collectionFactory) {
        Objects.requireNonNull(collectionFactory, "collectionFactory is required");
        return getEntities().collect(Collectors.toCollection(collectionFactory));
    }

    @Override
    public Stream get() {
        return getEntities();
    }

    private Stream getEntities() {
        if (Objects.isNull(entitiesCache)) {
            synchronized (this) {
                this.entitiesCache = entities.collect(Collectors.toList());
            }
        }
        return entitiesCache.stream();
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        ColumnPage that = (ColumnPage) o;
        return Objects.equals(entities, that.entities) &&
                Objects.equals(query, that.query);
    }

    @Override
    public int hashCode() {
        return Objects.hash(entities, query);
    }

    @Override
    public String toString() {
        return "ColumnPage{" +
                "entities=" + entities +
                ", query=" + query +
                '}';
    }
}