it.f2informatica.pagination.response.DatatablePaginationResponse.java Source code

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Here is the source code for it.f2informatica.pagination.response.DatatablePaginationResponse.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.response;

import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.mysema.query.Tuple;
import it.f2informatica.pagination.services.QueryParameters;
import it.f2informatica.pagination.utils.SafeGetterMethodExecutor;
import org.apache.commons.lang3.ArrayUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.stereotype.Service;

import java.util.List;
import java.util.Map;

@Service
public class DatatablePaginationResponse implements PaginationResponse {

    @Autowired
    private SafeGetterMethodExecutor safeGetterMethodExecutor;

    @Override
    public <T> Map<String, Object> generateResponseAttributes(QueryParameters queryParameters,
            Page<T> paginatedQueryResult) {
        final boolean hasContent = paginatedQueryResult.hasContent();
        Map<String, Object> datatableAttributes = Maps.newHashMap();
        datatableAttributes.put("sEcho", queryParameters.getEcho());
        datatableAttributes.put("iTotalRecords", (hasContent) ? paginatedQueryResult.getTotalElements() : 0L);
        datatableAttributes.put("iTotalDisplayRecords",
                (hasContent) ? paginatedQueryResult.getTotalElements() : 0L);
        datatableAttributes.put("aaData", convertResultAsArray(paginatedQueryResult, queryParameters));
        return datatableAttributes;
    }

    private <T> Object[] convertResultAsArray(Page<T> paginatedQueryResult, QueryParameters parameters) {
        return paginatedQueryResult.hasContent()
                ? Iterables.toArray(transformDataRowOneByOne(parameters, paginatedQueryResult), Object.class)
                : ArrayUtils.EMPTY_OBJECT_ARRAY;
    }

    private <T> List<Map<String, Object>> transformDataRowOneByOne(QueryParameters parameters,
            Page<T> paginatedQueryResult) {
        List<Map<String, Object>> data = Lists.newArrayList();
        for (T entity : paginatedQueryResult.getContent()) {
            T tuple = resolveTuple(entity);
            Map<String, Object> row = Maps.newHashMap();
            for (int columnIndex = 0; columnIndex < parameters.getColumnsNumber(); columnIndex++) {
                String field = parameters.getColumnName(columnIndex);
                row.put(field, safeGetterMethodExecutor.invokeGetterOnField(field, tuple));
            }
            data.add(row);
        }
        return data;
    }

    @SuppressWarnings("unchecked")
    private <T> T resolveTuple(T entity) {
        if (entity instanceof Tuple) {
            return (T) ((Tuple) entity).toArray()[0];
        }
        return entity;
    }

}