it.f2informatica.pagination.services.PageableFactoryImpl.java Source code

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Here is the source code for it.f2informatica.pagination.services.PageableFactoryImpl.java

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/*
 * =============================================================================
 *
 *   Copyright (c) 2014, Fernando Aspiazu
 *
 *   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 it.f2informatica.pagination.services;

import com.google.common.base.Optional;
import com.google.common.collect.Lists;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.stereotype.Service;
import org.springframework.util.StringUtils;

import java.util.List;

@Service
public class PageableFactoryImpl implements PageableFactory {
    private static final String UNIQUE_PREFIX = "unique";

    @Override
    public Pageable getPageable(QueryParameters parameters) {
        int page = parameters.getPage(), size = parameters.getSize();
        Optional<Sort> sort = getSort(parameters);
        return sort.isPresent() ? new PageRequest(page, size, sort.get()) : new PageRequest(page, size);
    }

    @Override
    public Optional<Sort> getSort(QueryParameters parameters) {
        final String sortColumn = parameters.getSortColumn();
        final String sortDirection = parameters.getSortDirection();

        return (StringUtils.hasText(sortColumn) && StringUtils.hasText(sortDirection))
                ? Optional.of(new Sort(getDirection(sortDirection), suppressUniquePrefixIfAny(sortColumn)))
                : Optional.<Sort>absent();
    }

    @Override
    public Sort.Direction getDirection(String sortDirection) {
        Optional<Sort.Direction> direction = Optional.fromNullable(Sort.Direction.fromStringOrNull(sortDirection));
        return direction.isPresent() ? direction.get() : Sort.DEFAULT_DIRECTION;
    }

    private static String suppressUniquePrefixIfAny(String sortColumn) {
        final String separator = "_";
        if (sortColumn.contains(UNIQUE_PREFIX)) {
            List<String> realComposedField = Lists.newArrayList();
            for (String fakeField : sortColumn.split(separator)) {
                if (fakeField.startsWith(UNIQUE_PREFIX)) {
                    realComposedField.add(fakeField.substring(UNIQUE_PREFIX.length()).toLowerCase());
                    continue;
                }
                realComposedField.add(fakeField);
            }
            return org.apache.commons.lang3.StringUtils.join(realComposedField, separator).replace(separator, ".");
        }
        return sortColumn.replace(separator, ".");
    }

}