+ * This class is a helper for the query parser framework, it does all the three + * query parser phrases at once: text parsing, query processing and query + * building. + *
+ *+ * It contains methods that allows the user to change the implementation used on + * the three phases. + *
+ * + * @see QueryNodeProcessor + * @see SyntaxParser + * @see QueryBuilder + * @see QueryConfigHandler + */ +public class QueryParserHelper { + + private QueryNodeProcessor processor; + + private SyntaxParser syntaxParser; + + private QueryBuilder builder; + + private QueryConfigHandler config; + + /** + * Creates a query parser helper object using the specified configuration, + * text parser, processor and builder. + * + * @param queryConfigHandler + * the query configuration handler that will be initially set to this + * helper + * @param syntaxParser + * the text parser that will be initially set to this helper + * @param processor + * the query processor that will be initially set to this helper + * @param builder + * the query builder that will be initially set to this helper + * + * @see QueryNodeProcessor + * @see SyntaxParser + * @see QueryBuilder + * @see QueryConfigHandler + */ + public QueryParserHelper(QueryConfigHandler queryConfigHandler, SyntaxParser syntaxParser, QueryNodeProcessor processor, + QueryBuilder builder) { + this.syntaxParser = syntaxParser; + this.config = queryConfigHandler; + this.processor = processor; + this.builder = builder; + + if (processor != null) { + processor.setQueryConfigHandler(queryConfigHandler); + } + + } + + /** + * Returns the processor object used to process the query node tree, it + * returnsnull if no processor is used.
+ *
+ * @return the actual processor used to process the query node tree,
+ * null if no processor is used
+ *
+ * @see QueryNodeProcessor
+ * @see #setQueryNodeProcessor(QueryNodeProcessor)
+ */
+ public QueryNodeProcessor getQueryNodeProcessor() {
+ return processor;
+ }
+
+ /**
+ * Sets the processor that will be used to process the query node tree. If
+ * there is any {@link QueryConfigHandler} returned by
+ * {@link #getQueryConfigHandler()}, it will be set on the processor. The
+ * argument can be null, which means that no processor will be
+ * used to process the query node tree.
+ *
+ * @param processor
+ * the processor that will be used to process the query node tree,
+ * this argument can be null
+ *
+ * @see #getQueryNodeProcessor()
+ * @see QueryNodeProcessor
+ */
+ public void setQueryNodeProcessor(QueryNodeProcessor processor) {
+ this.processor = processor;
+ this.processor.setQueryConfigHandler(getQueryConfigHandler());
+
+ }
+
+ /**
+ * Sets the text parser that will be used to parse the query string, it cannot
+ * be null.
+ *
+ * @param syntaxParser
+ * the text parser that will be used to parse the query string
+ *
+ * @see #getSyntaxParser()
+ * @see SyntaxParser
+ */
+ public void setSyntaxParser(SyntaxParser syntaxParser) {
+
+ if (syntaxParser == null) {
+ throw new IllegalArgumentException("textParser should not be null!");
+ }
+
+ this.syntaxParser = syntaxParser;
+
+ }
+
+ /**
+ * The query builder that will be used to build an object from the query node
+ * tree. It cannot be null.
+ *
+ * @param queryBuilder
+ * the query builder used to build something from the query node tree
+ *
+ * @see #getQueryBuilder()
+ * @see QueryBuilder
+ */
+ public void setQueryBuilder(QueryBuilder queryBuilder) {
+
+ if (queryBuilder == null) {
+ throw new IllegalArgumentException("queryBuilder should not be null!");
+ }
+
+ this.builder = queryBuilder;
+
+ }
+
+ /**
+ * Returns the query configuration handler, which is used during the query
+ * node tree processing. It can be null.
+ *
+ * @return the query configuration handler used on the query processing,
+ * null if not query configuration handler is defined
+ *
+ * @see QueryConfigHandler
+ * @see #setQueryConfigHandler(QueryConfigHandler)
+ */
+ public QueryConfigHandler getQueryConfigHandler() {
+ return config;
+ }
+
+ /**
+ * Returns the query builder used to build a object from the query node tree.
+ * The object produced by this builder is returned by
+ * {@link #parse(String, String)}.
+ *
+ * @return the query builder
+ *
+ * @see #setQueryBuilder(QueryBuilder)
+ * @see QueryBuilder
+ */
+ public QueryBuilder getQueryBuilder() {
+ return this.builder;
+ }
+
+ /**
+ * Returns the text parser used to build a query node tree from a query
+ * string. The default text parser instance returned by this method is a
+ * {@link SyntaxParser}.
+ *
+ * @return the text parse used to build query node trees.
+ *
+ * @see SyntaxParser
+ * @see #setSyntaxParser(SyntaxParser)
+ */
+ public SyntaxParser getSyntaxParser() {
+ return this.syntaxParser;
+ }
+
+ /**
+ * Sets the query configuration handler that will be used during query
+ * processing. It can be null. It's also set to the processor
+ * returned by {@link #getQueryNodeProcessor()}.
+ *
+ * @param config
+ * the query configuration handler used during query processing, it
+ * can be null
+ *
+ * @see #getQueryConfigHandler()
+ * @see QueryConfigHandler
+ */
+ public void setQueryConfigHandler(QueryConfigHandler config) {
+ this.config = config;
+ QueryNodeProcessor processor = getQueryNodeProcessor();
+
+ if (processor != null) {
+ processor.setQueryConfigHandler(config);
+ }
+
+ }
+
+ /**
+ * Parses a query string to an object, usually some query object.