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/*
 * Copyright 2016-2023 the original author or authors from the JHipster project.
 *
 * This file is part of the JHipster project, see https://www.jhipster.tech/
 * for more information.
 *
 * 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 tech.jhipster.web.util;

import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageImpl;
import org.springframework.data.domain.Pageable;

import java.util.ArrayList;
import java.util.List;

/**
 * Utility class for creating a Page object.
 */
public interface PageUtil {

    /**
     * Create a {@link org.springframework.data.domain.Page} from a {@link java.util.List} of objects
     *
     * @param list list of objects
     * @param pageable pagination information.
     * @param  type of object
     * @return page containing objects, and attributes set according to pageable
     * @throws java.lang.IllegalArgumentException - if list is null
     */
    static  Page createPageFromList(List list, Pageable pageable) {
        if (list == null) {
            throw new IllegalArgumentException("To create a Page, the list mustn't be null!");
        }

        int startOfPage = pageable.getPageNumber() * pageable.getPageSize();
        if (startOfPage > list.size()) {
            return new PageImpl<>(new ArrayList<>(), pageable, 0);
        }

        int endOfPage = Math.min(startOfPage + pageable.getPageSize(), list.size());
        return new PageImpl<>(list.subList(startOfPage, endOfPage), pageable, list.size());
    }
}