org.openlmis.fulfillment.service.PageDto.java Source code

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Here is the source code for org.openlmis.fulfillment.service.PageDto.java

Source

/*
 * This program is part of the OpenLMIS logistics management information system platform software.
 * Copyright  2017 VillageReach
 *
 * This program is free software: you can redistribute it and/or modify it under the terms
 * of the GNU Affero General Public License as published by the Free Software Foundation, either
 * version 3 of the License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU Affero General Public License for more details. You should have received a copy of
 * the GNU Affero General Public License along with this program. If not, see
 * http://www.gnu.org/licenses. For additional information contact info@OpenLMIS.org.
 */

package org.openlmis.fulfillment.service;

import static com.google.common.base.Preconditions.checkNotNull;

import com.fasterxml.jackson.databind.annotation.JsonDeserialize;

import org.openlmis.fulfillment.util.CustomSortDeserializer;
import org.springframework.core.convert.converter.Converter;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageImpl;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;

import lombok.AllArgsConstructor;
import lombok.EqualsAndHashCode;
import lombok.Getter;
import lombok.Setter;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.stream.Collectors;

/**
 * PageDto offers a convenient substitute for PageImpl. Because the former lacks a default
 * constructor, it is inconvenient to deserialize. PageDto may be used in its stead.
 */
@Getter
@Setter
@AllArgsConstructor
@EqualsAndHashCode(callSuper = false)
public final class PageDto<T> implements Page<T> {
    private boolean last;
    private boolean first;

    private int totalPages;
    private long totalElements;
    private int size;
    private int number;
    private int numberOfElements;

    @JsonDeserialize(using = CustomSortDeserializer.class)
    private Sort sort;

    private List<T> content;

    public PageDto() {
        this(new PageImpl<>(new ArrayList<>()));
    }

    /**
     * Creates new instance based on data from {@link Page} instance.
     */
    public PageDto(Page<T> page) {
        this(checkNotNull(page).isLast(), page.isFirst(), page.getTotalPages(), page.getTotalElements(),
                page.getSize(), page.getNumber(), page.getNumberOfElements(), page.getSort(),
                checkNotNull(page.getContent()));
    }

    @Override
    public boolean hasContent() {
        return !content.isEmpty();
    }

    @Override
    public boolean hasNext() {
        return !last;
    }

    @Override
    public boolean hasPrevious() {
        return !first;
    }

    @Override
    public Pageable nextPageable() {
        return hasNext() ? new PageRequest(number + 1, size, sort) : null;
    }

    @Override
    public Pageable previousPageable() {
        return hasPrevious() ? new PageRequest(number - 1, size, sort) : new PageRequest(0, size, sort);
    }

    @Override
    public <S> Page<S> map(Converter<? super T, ? extends S> converter) {
        checkNotNull(converter);

        List<S> result = content.stream().map(converter::convert).collect(Collectors.toList());
        Pageable pageable = new PageRequest(number, size, sort);
        Page<S> page = new PageImpl<>(result, pageable, totalElements);

        return new PageDto<>(page);
    }

    @Override
    public Iterator<T> iterator() {
        return content.iterator();
    }
}