| /* |
| * 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.search; |
| |
| import org.apache.lucene.search.Query; |
| import org.apache.solr.common.params.SolrParams; |
| import org.apache.solr.common.util.NamedList; |
| import org.apache.solr.request.SolrQueryRequest; |
| import org.apache.solr.handler.component.SearchHandler; // jdoc |
| |
| import org.apache.commons.lang3.StringUtils; |
| |
| /** |
| * <p>A QParserPlugin that acts like a "switch/case" statement.</p> |
| * |
| * <p> |
| * QParser's produced by this plugin will take their primary input string, |
| * trimmed and prefixed with "<code>case.</code>", to use as a key to lookup a |
| * "switch case" in the parser's local params. If a matching local param is |
| * found the resulting param value will then be parsed as a subquery, and |
| * returned as the parse result. |
| * </p> |
| * <p> |
| * The "<code>case</code>" local param can be optionally be specified as a |
| * switch case to match missing (or blank) input strings. |
| * The "<code>default</code>" local param can optionally be specified |
| * as a default case to use if the input string does not match any other |
| * switch case local params. If <code>default</code> is not specified, |
| * then any input which does not match a switch case local param will result |
| * in a syntax error. |
| * </p> |
| * |
| * <p> |
| * In the examples below, the result of each query would be <code>XXX</code>.... |
| * </p> |
| * <pre> |
| * q={!switch case.foo=XXX case.bar=zzz case.yak=qqq}foo |
| * q={!switch case.foo=qqq case.bar=XXX case.yak=zzz} bar // extra whitespace |
| * q={!switch case.foo=qqq case.bar=zzz default=XXX}asdf // fallback on default |
| * q={!switch case=XXX case.bar=zzz case.yak=qqq} // blank input |
| * </pre> |
| * |
| * <p> |
| * A practical usage of this QParsePlugin, is in specifying "appends" |
| * <code>fq</code> params in the configuration of a {@link SearchHandler}, to |
| * provide a fixed set of filter options for clients using custom parameter |
| * names. |
| * Using the example configuration below, clients can optionally specify the |
| * custom parameters <code>in_stock</code> and <code>shipping</code> to |
| * override the default filtering behavior, but are limited to the specific |
| * set of legal values (<code>shipping=any|free</code>, |
| * <code>in_stock=yes|no|all</code>). |
| * </p> |
| * |
| * <pre class="prettyprint"> |
| * <requestHandler name="/select" class="solr.SearchHandler"> |
| * <lst name="defaults"> |
| * <str name="in_stock">yes</str> |
| * <str name="shipping">any</str> |
| * </lst> |
| * <lst name="appends"> |
| * <str name="fq">{!switch case.all='*:*' |
| * case.yes='inStock:true' |
| * case.no='inStock:false' |
| * v=$in_stock}</str> |
| * <str name="fq">{!switch case.any='*:*' |
| * case.free='shipping_cost:0.0' |
| * v=$shipping}</str> |
| * </lst> |
| * </requestHandler></pre> |
| * |
| * <p> |
| * A slightly more interesting variant of the <code>shipping</code> example above, would be |
| * to combine the switch parser with the frange parser, to allow the client to specify an |
| * arbitrary "max shipping" amount that will be used to build a filter if and only if a |
| * value is specified. Example: |
| * </p> |
| * <pre class="prettyprint"> |
| * <requestHandler name="/select" class="solr.SearchHandler"> |
| * <lst name="invariants"> |
| * <str name="shipping_fq">{!frange u=$shipping}shipping_cost</str> |
| * </lst> |
| * <lst name="defaults"> |
| * <str name="shipping">any</str> |
| * </lst> |
| * <lst name="appends"> |
| * <str name="fq">{!switch case='*:*' |
| * case.any='*:*' |
| * default=$shipping_fq |
| * v=$shipping}</str> |
| * </lst> |
| * </requestHandler></pre> |
| * |
| * <p> |
| * With the above configuration a client that specifies <code>shipping=any</code>, or |
| * does not specify a <code>shipping</code> param at all, will not have the results |
| * filtered. But if a client specifies a numeric value (ie: <code>shipping=10</code>, |
| * <code>shipping=5</code>, etc..) then the results will be limited to documents whose |
| * <code>shipping_cost</code> field has a value less then that number. |
| * </p> |
| * |
| * <p> |
| * A similar use case would be to combine the switch parser with the bbox parser to |
| * support an optional geographic filter that is applied if and only if the client |
| * specifies a <code>location</code> param containing a lat,lon pair to be used as |
| * the center of the bounding box: |
| * </p> |
| * <pre class="prettyprint"> |
| * <requestHandler name="/select" class="solr.SearchHandler"> |
| * <lst name="invariants"> |
| * <str name="bbox_fq">{!bbox pt=$location sfield=geo d=$dist}</str> |
| * </lst> |
| * <lst name="defaults"> |
| * <str name="dist">100</str> |
| * </lst> |
| * <lst name="appends"> |
| * <str name="fq">{!switch case='*:*' |
| * default=$bbox_fq |
| * v=$location}</str> |
| * </lst> |
| * </requestHandler></pre> |
| */ |
| public class SwitchQParserPlugin extends QParserPlugin { |
| public static final String NAME = "switch"; |
| |
| /** |
| * Used as both a local params key to find the "default" if no |
| * blank input is provided to the parser, as well as a prefix (followed by |
| * '.' for looking up the switch input. |
| */ |
| public static String SWITCH_CASE = "case"; |
| |
| /** |
| * A local param whose value, if specified, is used if no switch case |
| * matches the parser input. If this param is not specified, and no |
| * switch case matches the parser input, an error is returned. |
| */ |
| public static String SWITCH_DEFAULT = "default"; |
| |
| @Override |
| public QParser createParser(String qstr, SolrParams localParams, SolrParams params, SolrQueryRequest req) { |
| return new QParser(qstr, localParams, params, req) { |
| QParser subParser; |
| |
| @Override |
| public Query parse() throws SyntaxError { |
| String val = localParams.get(QueryParsing.V); |
| |
| // we don't want to wrapDefaults arround params, because then |
| // clients could add their own switch options |
| String subQ = localParams.get(SWITCH_DEFAULT); |
| subQ = StringUtils.isBlank(val) |
| ? localParams.get(SWITCH_CASE, subQ) |
| : localParams.get(SWITCH_CASE + "." + val.trim(), subQ); |
| |
| if (null == subQ) { |
| throw new SyntaxError("No "+SWITCH_DEFAULT+", and no switch case matching specified query string: \"" + val + "\""); |
| } |
| |
| subParser = subQuery(subQ, null); |
| return subParser.getQuery(); |
| } |
| |
| @Override |
| public String[] getDefaultHighlightFields() { |
| return subParser.getDefaultHighlightFields(); |
| } |
| |
| @Override |
| public Query getHighlightQuery() throws SyntaxError { |
| return subParser.getHighlightQuery(); |
| } |
| |
| @Override |
| public void addDebugInfo(NamedList<Object> debugInfo) { |
| subParser.addDebugInfo(debugInfo); |
| } |
| }; |
| } |
| } |
