Elasticsearch源码分析九--查询解析器QueryParser注册过程

QueryParser及其子类用于对输入的查询query进行解析，返回Query类的对象，代表具体的查询类。
Elasticsearch为每种类型的Query提供了单独的查询解析器；而Lucene的QueryParser对所有类型的Query使用相同的查询解析器。
Lucene的解析器使用如下：

'''在构造QueryParser对象时传入分析器,此过程涉及JavaCC、分词器、查询语法等'''QueryParser parser = new QueryParser(Version.LUCENE_CURRENT, "contents", new StandardAnalyzer(Version.LUCENE_CURRENT));Query query = parser.parse("+(+apple* -boy) (cat* dog) -(eat~ foods)");

源码分析

'''(1)添加Query解析器及Filter解析器的实例对象'''public class IndicesQueriesModule extends AbstractModule {   protected void configure() {        bind(IndicesQueriesRegistry.class).asEagerSingleton();        Multibinder<QueryParser> qpBinders = Multibinder.newSetBinder(binder(), QueryParser.class);        for (Class<QueryParser> queryParser : queryParsersClasses) {            qpBinders.addBinding().to(queryParser).asEagerSingleton();        }        for (QueryParser queryParser : queryParsers) {            qpBinders.addBinding().toInstance(queryParser);        }'''(1)添加Query解析器实例对象'''       qpBinders.addBinding().to(MatchQueryParser.class).asEagerSingleton();        qpBinders.addBinding().to(MultiMatchQueryParser.class).asEagerSingleton();        qpBinders.addBinding().to(NestedQueryParser.class).asEagerSingleton();        qpBinders.addBinding().to(HasChildQueryParser.class).asEagerSingleton();        qpBinders.addBinding().to(HasParentQueryParser.class).asEagerSingleton();        qpBinders.addBinding().to(TopChildrenQueryParser.class).asEagerSingleton();        qpBinders.addBinding().to(DisMaxQueryParser.class).asEagerSingleton();        qpBinders.addBinding().to(IdsQueryParser.class).asEagerSingleton();        qpBinders.addBinding().to(MatchAllQueryParser.class).asEagerSingleton();        qpBinders.addBinding().to(QueryStringQueryParser.class).asEagerSingleton();        qpBinders.addBinding().to(BoostingQueryParser.class).asEagerSingleton();        qpBinders.addBinding().to(BoolQueryParser.class).asEagerSingleton();        qpBinders.addBinding().to(TermQueryParser.class).asEagerSingleton();        qpBinders.addBinding().to(TermsQueryParser.class).asEagerSingleton();        qpBinders.addBinding().to(FuzzyQueryParser.class).asEagerSingleton();        qpBinders.addBinding().to(RegexpQueryParser.class).asEagerSingleton();        qpBinders.addBinding().to(FieldQueryParser.class).asEagerSingleton();        qpBinders.addBinding().to(RangeQueryParser.class).asEagerSingleton();        qpBinders.addBinding().to(PrefixQueryParser.class).asEagerSingleton();        qpBinders.addBinding().to(WildcardQueryParser.class).asEagerSingleton();'''省略...''''''(2)添加Filter解析器实例对象'''        fpBinders.addBinding().to(HasChildFilterParser.class).asEagerSingleton();        fpBinders.addBinding().to(HasParentFilterParser.class).asEagerSingleton();  '''省略...'''      }}'''(2)Query/Filter类型-Query/Filter解析器实例对象对应关系注册'''public class IndexQueryParserService extends AbstractIndexComponent {      '''Query类型-Query解析器实例对象映射关系'''    private final Map<String, QueryParser> queryParsers;    '''Filter类型-Filter解析器实例对象映射关系'''    private final Map<String, FilterParser> filterParsers;    public IndexQueryParserService(Index index, @IndexSettings Settings indexSettings,                                   IndicesQueriesRegistry indicesQueriesRegistry, CacheRecycler cacheRecycler,                                   ScriptService scriptService, AnalysisService analysisService,                                   MapperService mapperService, IndexCache indexCache, IndexFieldDataService fieldDataService, IndexEngine indexEngine,                                   @Nullable SimilarityService similarityService,                                   @Nullable Map<String, QueryParserFactory> namedQueryParsers,                                   @Nullable Map<String, FilterParserFactory> namedFilterParsers) {        super(index, indexSettings);        this.cacheRecycler = cacheRecycler;        this.scriptService = scriptService;        this.analysisService = analysisService;        this.mapperService = mapperService;        this.similarityService = similarityService;        this.indexCache = indexCache;        this.fieldDataService = fieldDataService;        this.indexEngine = indexEngine;        this.defaultField = indexSettings.get("index.query.default_field", AllFieldMapper.NAME);        this.queryStringLenient = indexSettings.getAsBoolean("index.query_string.lenient", false);        List<QueryParser> queryParsers = newArrayList();        if (namedQueryParsers != null) {            Map<String, Settings> queryParserGroups = indexSettings.getGroups(IndexQueryParserService.Defaults.QUERY_PREFIX);            for (Map.Entry<String, QueryParserFactory> entry : namedQueryParsers.entrySet()) {                String queryParserName = entry.getKey();                QueryParserFactory queryParserFactory = entry.getValue();                Settings queryParserSettings = queryParserGroups.get(queryParserName);                if (queryParserSettings == null) {                    queryParserSettings = EMPTY_SETTINGS;                }                queryParsers.add(queryParserFactory.create(queryParserName, queryParserSettings));            }        }        Map<String, QueryParser> queryParsersMap = newHashMap();        queryParsersMap.putAll(indicesQueriesRegistry.queryParsers());        if (queryParsers != null) {            '''添加Query类型-Query解析器实例对象到Map中'''            for (QueryParser queryParser : queryParsers) {                add(queryParsersMap, queryParser);            }        }        this.queryParsers = ImmutableMap.copyOf(queryParsersMap);        List<FilterParser> filterParsers = newArrayList();        if (namedFilterParsers != null) {            Map<String, Settings> filterParserGroups = indexSettings.getGroups(IndexQueryParserService.Defaults.FILTER_PREFIX);            for (Map.Entry<String, FilterParserFactory> entry : namedFilterParsers.entrySet()) {                String filterParserName = entry.getKey();                FilterParserFactory filterParserFactory = entry.getValue();                Settings filterParserSettings = filterParserGroups.get(filterParserName);                if (filterParserSettings == null) {                    filterParserSettings = EMPTY_SETTINGS;                }                filterParsers.add(filterParserFactory.create(filterParserName, filterParserSettings));            }        }        Map<String, FilterParser> filterParsersMap = newHashMap();        filterParsersMap.putAll(indicesQueriesRegistry.filterParsers());        if (filterParsers != null) {            '''添加Filter类型-Filter解析器实例对象到Map中'''            for (FilterParser filterParser : filterParsers) {                add(filterParsersMap, filterParser);            }        }        this.filterParsers = ImmutableMap.copyOf(filterParsersMap);    }}  '''(3)提供接口根据name获取解析器实例对象'''public class IndexQueryParserService extends AbstractIndexComponent {    '''根据Query名字获取Query解析器实例对象'''    public QueryParser queryParser(String name) {        return queryParsers.get(name);    }    '''根据Filter名字获取Filter解析器实例对象'''    public FilterParser filterParser(String name) {        return filterParsers.get(name);    }}'''(4)Map的Key定义即Query类型和Filter类型来源'''public class WildcardQueryParser implements QueryParser {    '''Query类型定义'''    public static final String NAME = "wildcard";    @Override    '''Query类型获取接口'''    public String[] names() {        return new String[]{NAME};    }}public class PrefixFilterParser implements FilterParser {    '''Filter类型'''    public static final String NAME = "prefix";    '''Filter类型获取接口'''    @Override    public String[] names() {        return new String[]{NAME};    }}

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