org.ambraproject.wombat.model.SearchFilterFactory.java Source code

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Here is the source code for org.ambraproject.wombat.model.SearchFilterFactory.java

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/*
 * Copyright (c) 2017 Public Library of Science
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

package org.ambraproject.wombat.model;

import com.google.common.collect.LinkedListMultimap;
import com.google.common.collect.ListMultimap;
import com.google.common.collect.Multimap;
import com.google.common.collect.Multimaps;
import org.springframework.beans.factory.annotation.Autowired;

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

/**
 * This class is used exclusively in the @code{SearchFilterService} to create @code{SearchFilter}s
 * from faceted search results returned from Solr.
 */
public class SearchFilterFactory {

    @Autowired
    private SearchFilterTypeMap filterTypeMap;

    /**
     * The main create method of the factory. Creates a @code{SearchFilter} in three steps:
     *
     * 1. Retrieve the specified @code{SearchFilterType} using the @code{SearchFilterTypeMap}
     * 2. Parse the results from a faceted search into individual @code{SearchFilterItem}s
     * 3. Combine all SearchFilterItems into a @code{SearchFilter} object.
     *
     * Note that the @code{ArticleSearchQuery.Builder} query must be set as a faceted search
     * by calling setFacet()
     *
     * @param results faceted search results returned from Solr
     * @param filterTypeMapKey key for the filter type
     * @param params URL parameters applicable to the search
     * @return @code{SearchFilter} object made up of one or many @code{SearchFilterItems} that contain
     * the faceted search results. The SearchFilterItems also house a /search URL that represents
     * how the filter would be applied or removed from a search.
     */
    public SearchFilter createSearchFilter(Map<?, ?> results, String filterTypeMapKey,
            Multimap<String, String> params) {

        SearchFilterType filterType = filterTypeMap.getSearchFilterByKey(filterTypeMapKey);

        List<SearchFilterItem> searchFilterResult = new ArrayList<>();

        for (Map.Entry<?, ?> entry : results.entrySet()) {

            Double numberOfHits = (Double) entry.getValue();

            //displayName is often represented by the filter value
            String displayName = entry.getKey().toString();

            ListMultimap<String, String> changedParams = applyFilterToParams(displayName, params, filterType);
            SearchFilterItem filterItem = new SearchFilterItem(displayName, numberOfHits.floatValue(),
                    filterType.getParameterName(), filterType.getFilterValue(displayName),
                    Multimaps.asMap(changedParams));
            searchFilterResult.add(filterItem);
        }
        return new SearchFilter(searchFilterResult, filterTypeMapKey);
    }

    /**
     * Examines the current URL parameters, and toggles the selected parameter.
     *
     * @param displayName used to retrieve the filter value from the filter type map
     * @param params current URL parameters to be modified
     * @param filterType used to retrieve selected filter parameter name and value
     * @return filtered URL parameter List
     */
    private ListMultimap<String, String> applyFilterToParams(String displayName, Multimap<String, String> params,
            SearchFilterType filterType) {
        String filterValue = filterType.getFilterValue(displayName);
        String parameterName = filterType.getParameterName();

        ListMultimap<String, String> changedParams = LinkedListMultimap.create(params);
        if (params.containsEntry(parameterName, filterValue)) {
            changedParams.remove(parameterName, filterValue);
        } else {
            changedParams.put(parameterName, filterValue);
        }
        return changedParams;
    }

}