Java tutorial
/* * Copyright 2012 the original author or authors. * * 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 org.springframework.data.solr.core; import java.util.ArrayList; import java.util.List; import org.apache.commons.lang.StringUtils; import org.apache.solr.client.solrj.SolrQuery; import org.apache.solr.client.solrj.SolrQuery.ORDER; import org.apache.solr.client.solrj.SolrServer; import org.apache.solr.common.params.CommonParams; import org.apache.solr.common.params.FacetParams; import org.apache.solr.common.params.GroupParams; import org.springframework.dao.InvalidDataAccessApiUsageException; import org.springframework.data.domain.Pageable; import org.springframework.data.domain.Sort; import org.springframework.data.domain.Sort.Order; import org.springframework.data.solr.core.query.FacetOptions; import org.springframework.data.solr.core.query.FacetQuery; import org.springframework.data.solr.core.query.Field; import org.springframework.data.solr.core.query.FilterQuery; import org.springframework.data.solr.core.query.Query; import org.springframework.data.solr.core.query.SolrDataQuery; import org.springframework.util.Assert; import org.springframework.util.CollectionUtils; /** * The QueryParser takes a spring-data-solr Query and returns a SolrQuery. All Query parameters are translated into the * according SolrQuery fields. <b>Example:</b> <code> * Query query = new SimpleQuery(new Criteria("field_1").is("value_1").and("field_2").startsWith("value_2")).addProjection("field_3").setPageRequest(new PageRequest(0, 10)); * </code> Will be parsed to a SolrQuery that outputs the following <code> * q=field_1%3Avalue_1+AND+field_2%3Avalue_2*&fl=field_3&start=0&rows=10 * </code> * * @author Christoph Strobl */ public class QueryParser { /** * Convert given Query into a SolrQuery executable via {@link SolrServer} * * @param query * @return */ public final SolrQuery constructSolrQuery(SolrDataQuery query) { Assert.notNull(query, "Cannot construct solrQuery from null value."); Assert.notNull(query.getCriteria(), "Query has to have a criteria."); SolrQuery solrQuery = new SolrQuery(); solrQuery.setParam(CommonParams.Q, getQueryString(query)); if (query instanceof Query) { processQueryOptions(solrQuery, (Query) query); } if (query instanceof FacetQuery) { processFacetOptions(solrQuery, (FacetQuery) query); } return solrQuery; } private void processQueryOptions(SolrQuery solrQuery, Query query) { appendPagination(solrQuery, query.getPageRequest()); appendProjectionOnFields(solrQuery, query.getProjectionOnFields()); appendGroupByFields(solrQuery, query.getGroupByFields()); appendFilterQuery(solrQuery, query.getFilterQueries()); appendSort(solrQuery, query.getSort()); } private void processFacetOptions(SolrQuery solrQuery, FacetQuery query) { appendFacetingOnFields(solrQuery, (FacetQuery) query); } /** * Get the queryString to use withSolrQuery.setParam(CommonParams.Q, "queryString"} * * @param query * @return String representation of query without faceting, pagination, projection... */ public String getQueryString(SolrDataQuery query) { if (query.getCriteria() == null) { return null; } return query.getCriteria().createQueryString(); } private void appendPagination(SolrQuery query, Pageable pageable) { if (pageable == null) { return; } query.setStart(pageable.getOffset()); query.setRows(pageable.getPageSize()); } private void appendProjectionOnFields(SolrQuery solrQuery, List<Field> fields) { if (CollectionUtils.isEmpty(fields)) { return; } solrQuery.setParam(CommonParams.FL, StringUtils.join(fields, ",")); } private void appendFacetingOnFields(SolrQuery solrQuery, FacetQuery query) { FacetOptions facetOptions = query.getFacetOptions(); if (facetOptions == null || !facetOptions.hasFields()) { return; } solrQuery.setFacet(true); solrQuery.addFacetField(convertFieldListToStringArray(facetOptions.getFacetOnFields())); solrQuery.setFacetMinCount(facetOptions.getFacetMinCount()); solrQuery.setFacetLimit(facetOptions.getPageable().getPageSize()); if (facetOptions.getPageable().getPageNumber() > 0) { solrQuery.set(FacetParams.FACET_OFFSET, facetOptions.getPageable().getOffset()); } if (FacetOptions.FacetSort.INDEX.equals(facetOptions.getFacetSort())) { solrQuery.setFacetSort(FacetParams.FACET_SORT_INDEX); } } private void appendGroupByFields(SolrQuery solrQuery, List<Field> fields) { if (CollectionUtils.isEmpty(fields)) { return; } if (fields.size() > 1) { // there is a bug in solj which prevents multiple grouping // although available via HTTP call throw new InvalidDataAccessApiUsageException( "Cannot group on more than one field with current SolrJ API. Group on single field insead"); } solrQuery.set(GroupParams.GROUP, true); solrQuery.setParam(GroupParams.GROUP_MAIN, true); for (Field field : fields) { solrQuery.add(GroupParams.GROUP_FIELD, field.getName()); } } private void appendFilterQuery(SolrQuery solrQuery, List<FilterQuery> filterQueries) { if (CollectionUtils.isEmpty(filterQueries)) { return; } List<String> filterQueryStrings = getFilterQueryStrings(filterQueries); if (!filterQueryStrings.isEmpty()) { solrQuery.setFilterQueries(convertStringListToArray(filterQueryStrings)); } } private void appendSort(SolrQuery solrQuery, Sort sort) { if (sort == null) { return; } for (Order order : sort) { solrQuery.addSortField(order.getProperty(), order.isAscending() ? ORDER.asc : ORDER.desc); } } private String[] convertFieldListToStringArray(List<Field> fields) { String[] strResult = new String[fields.size()]; for (int i = 0; i < fields.size(); i++) { strResult[i] = fields.get(i).getName(); } return strResult; } private String[] convertStringListToArray(List<String> listOfString) { String[] strResult = new String[listOfString.size()]; listOfString.toArray(strResult); return strResult; } private List<String> getFilterQueryStrings(List<FilterQuery> filterQueries) { List<String> filterQueryStrings = new ArrayList<String>(filterQueries.size()); for (FilterQuery filterQuery : filterQueries) { String filterQueryString = getQueryString(filterQuery); if (StringUtils.isNotBlank(filterQueryString)) { filterQueryStrings.add(filterQueryString); } } return filterQueryStrings; } }