home | career | drupal | java | mac | mysql | perl | scala | uml | unix  

Lucene example source code file (TestSpanQueryParserSimpleSample.java)

This example Lucene source code file (TestSpanQueryParserSimpleSample.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Lucene tags/keywords

exception, management, queryconfighandler, querynode, querynodeprocessorpipeline, querynodeprocessorpipeline, spanquery, spansquerytreebuilder, spansquerytreebuilder, standardsyntaxparser, syntaxparser, testspanqueryparsersimplesample, uniquefieldattribute, uniquefieldquerynodeprocessor, uniquefieldquerynodeprocessor

The Lucene TestSpanQueryParserSimpleSample.java source code

package org.apache.lucene.queryParser.spans;

/**
 * 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.
 */

import javax.management.Query;

import org.apache.lucene.queryParser.core.config.QueryConfigHandler;
import org.apache.lucene.queryParser.core.nodes.OrQueryNode;
import org.apache.lucene.queryParser.core.nodes.QueryNode;
import org.apache.lucene.queryParser.core.parser.SyntaxParser;
import org.apache.lucene.queryParser.core.processors.QueryNodeProcessorPipeline;
import org.apache.lucene.queryParser.standard.parser.StandardSyntaxParser;
import org.apache.lucene.search.spans.SpanQuery;
import org.apache.lucene.search.spans.SpanTermQuery;
import org.apache.lucene.util.LuceneTestCase;

/**
 * This test case demonstrates how the new query parser can be used.<br/>
 * <br/>
 * 
 * It tests queries likes "term", "field:term" "term1 term2" "term1 OR term2",
 * which are all already supported by the current syntax parser (
 * {@link StandardSyntaxParser}).<br/>
 * <br/>
 * 
 * The goals is to create a new query parser that supports only the pair
 * "field:term" or a list of pairs separated or not by an OR operator, and from
 * this query generate {@link SpanQuery} objects instead of the regular
 * {@link Query} objects. Basically, every pair will be converted to a
 * {@link SpanTermQuery} object and if there are more than one pair they will be
 * grouped by an {@link OrQueryNode}.<br/>
 * <br/>
 * 
 * Another functionality that will be added is the ability to convert every
 * field defined in the query to an unique specific field.<br/>
 * <br/>
 * 
 * The query generation is divided in three different steps: parsing (syntax),
 * processing (semantic) and building.<br/>
 * <br/>
 * 
 * The parsing phase, as already mentioned will be performed by the current
 * query parser: {@link StandardSyntaxParser}.<br/>
 * <br/>
 * 
 * The processing phase will be performed by a processor pipeline which is
 * compound by 2 processors: {@link SpansValidatorQueryNodeProcessor} and
 * {@link UniqueFieldQueryNodeProcessor}.
 * 
 * <pre>
 * 
 *   {@link SpansValidatorQueryNodeProcessor}: as it's going to use the current 
 *   query parser to parse the syntax, it will support more features than we want,
 *   this processor basically validates the query node tree generated by the parser
 *   and just let got through the elements we want, all the other elements as 
 *   wildcards, range queries, etc...if found, an exception is thrown.
 *   
 *   {@link UniqueFieldQueryNodeProcessor}: this processor will take care of reading
 *   what is the "unique field" from the configuration and convert every field defined
 *   in every pair to this "unique field". For that, a {@link SpansQueryConfigHandler} is
 *   used, which has the {@link UniqueFieldAttribute} defined in it.
 * </pre>
 * 
 * The building phase is performed by the {@link SpansQueryTreeBuilder}, which
 * basically contains a map that defines which builder will be used to generate
 * {@link SpanQuery} objects from {@link QueryNode} objects.<br/>
 * <br/>
 * 
 * @see TestSpanQueryParser for a more advanced example
 * 
 * @see SpansQueryConfigHandler
 * @see SpansQueryTreeBuilder
 * @see SpansValidatorQueryNodeProcessor
 * @see SpanOrQueryNodeBuilder
 * @see SpanTermQueryNodeBuilder
 * @see StandardSyntaxParser
 * @see UniqueFieldQueryNodeProcessor
 * @see UniqueFieldAttribute
 * 
 */
public class TestSpanQueryParserSimpleSample extends LuceneTestCase {

  public void testBasicDemo() throws Exception {
    SyntaxParser queryParser = new StandardSyntaxParser();

    // convert the CharSequence into a QueryNode tree
    QueryNode queryTree = queryParser.parse("body:text", null);

    // create a config handler with a attribute used in
    // UniqueFieldQueryNodeProcessor
    QueryConfigHandler spanQueryConfigHandler = new SpansQueryConfigHandler();
    UniqueFieldAttribute uniqueFieldAtt = spanQueryConfigHandler
        .getAttribute(UniqueFieldAttribute.class);
    uniqueFieldAtt.setUniqueField("index");

    // set up the processor pipeline with the ConfigHandler
    // and create the pipeline for this simple demo
    QueryNodeProcessorPipeline spanProcessorPipeline = new QueryNodeProcessorPipeline(
        spanQueryConfigHandler);
    // @see SpansValidatorQueryNodeProcessor
    spanProcessorPipeline.add(new SpansValidatorQueryNodeProcessor());
    // @see UniqueFieldQueryNodeProcessor
    spanProcessorPipeline.add(new UniqueFieldQueryNodeProcessor());

    // print to show out the QueryNode tree before being processed
    if (VERBOSE) System.out.println(queryTree);

    // Process the QueryTree using our new Processors
    queryTree = spanProcessorPipeline.process(queryTree);

    // print to show out the QueryNode tree after being processed
    if (VERBOSE) System.out.println(queryTree);

    // create a instance off the Builder
    SpansQueryTreeBuilder spansQueryTreeBuilder = new SpansQueryTreeBuilder();

    // convert QueryNode tree to span query Objects
    SpanQuery spanquery = spansQueryTreeBuilder.build(queryTree);

    assertTrue(spanquery instanceof SpanTermQuery);
    assertEquals(spanquery.toString(), "index:text");

  }

}

Other Lucene examples (source code examples)

Here is a short list of links related to this Lucene TestSpanQueryParserSimpleSample.java source code file:



my book on functional programming

 

new blog posts

 

Copyright 1998-2019 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.