| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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.apache.solr.update.processor; |
| |
| import org.apache.solr.common.SolrInputField; |
| import org.apache.solr.request.SolrQueryRequest; |
| import org.apache.solr.response.SolrQueryResponse; |
| |
| import static org.apache.solr.update.processor.FieldMutatingUpdateProcessor.mutator; |
| |
| /** |
| * <p> |
| * Replaces any list of values for a field matching the specified |
| * conditions with the the count of the number of values for that field. |
| * </p> |
| * <p> |
| * By default, this processor matches no fields. |
| * </p> |
| * <p> |
| * The typical use case for this processor would be in combination with the |
| * {@link CloneFieldUpdateProcessorFactory} so that it's possible to query by |
| * the quantity of values in the source field. |
| * <p> |
| * For example, in the configuration below, the end result will be that the |
| * <code>category_count</code> field can be used to search for documents based |
| * on how many values they contain in the <code>category</code> field. |
| * </p> |
| * |
| * <pre class="prettyprint"> |
| * <processor class="solr.CloneFieldUpdateProcessorFactory"> |
| * <str name="source">category</str> |
| * <str name="dest">category_count</str> |
| * </processor> |
| * <processor class="solr.CountFieldValuesUpdateProcessorFactory"> |
| * <str name="fieldName">category_count</str> |
| * </processor> |
| * <processor class="solr.DefaultValueUpdateProcessorFactory"> |
| * <str name="fieldName">category_count</str> |
| * <int name="value">0</int> |
| * </processor></pre> |
| * |
| * <p> |
| * <b>NOTE:</b> The use of {@link DefaultValueUpdateProcessorFactory} is |
| * important in this example to ensure that all documents have a value for the |
| * <code>category_count</code> field, because |
| * <code>CountFieldValuesUpdateProcessorFactory</code> only <i>replaces</i> the |
| * list of values with the size of that list. If |
| * <code>DefaultValueUpdateProcessorFactory</code> was not used, then any |
| * document that had no values for the <code>category</code> field, would also |
| * have no value in the <code>category_count</code> field. |
| * </p> |
| * @since 4.0.0 |
| */ |
| public final class CountFieldValuesUpdateProcessorFactory extends FieldMutatingUpdateProcessorFactory { |
| |
| @Override |
| public UpdateRequestProcessor getInstance(SolrQueryRequest req, |
| SolrQueryResponse rsp, |
| UpdateRequestProcessor next) { |
| return mutator(getSelector(), next, src -> { |
| SolrInputField result = new SolrInputField(src.getName()); |
| result.setValue(src.getValueCount()); |
| return result; |
| }); |
| } |
| } |
| |