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/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.index.query.functionscore;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableMap.Builder;
import org.apache.lucene.search.BooleanClause.Occur;
import org.apache.lucene.search.BooleanQuery;
import org.apache.lucene.search.ConstantScoreQuery;
import org.apache.lucene.search.Query;
import org.elasticsearch.ElasticsearchParseException;
import org.elasticsearch.common.ParseField;
import org.elasticsearch.common.Strings;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.lucene.search.Queries;
import org.elasticsearch.common.lucene.search.function.CombineFunction;
import org.elasticsearch.common.lucene.search.function.FiltersFunctionScoreQuery;
import org.elasticsearch.common.lucene.search.function.FunctionScoreQuery;
import org.elasticsearch.common.lucene.search.function.ScoreFunction;
import org.elasticsearch.common.lucene.search.function.WeightFactorFunction;
import org.elasticsearch.common.xcontent.XContentParser;
import org.elasticsearch.index.query.QueryParseContext;
import org.elasticsearch.index.query.QueryParser;
import org.elasticsearch.index.query.QueryParsingException;
import org.elasticsearch.index.query.functionscore.factor.FactorParser;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
/**
*
*/
public class FunctionScoreQueryParser implements QueryParser {
public static final String NAME = "function_score";
// For better readability of error message
static final String MISPLACED_FUNCTION_MESSAGE_PREFIX = "you can either define [functions] array or a single function, not both. ";
static final String MISPLACED_BOOST_FUNCTION_MESSAGE_SUFFIX = " did you mean [boost] instead?";
public static final ParseField WEIGHT_FIELD = new ParseField("weight");
private static final ParseField FILTER_FIELD = new ParseField("filter").withAllDeprecated("query");
ScoreFunctionParserMapper functionParserMapper;
@Inject
public FunctionScoreQueryParser(ScoreFunctionParserMapper functionParserMapper) {
this.functionParserMapper = functionParserMapper;
}
@Override
public String[] names() {
return new String[] { NAME };
}
private static final ImmutableMap combineFunctionsMap;
static {
CombineFunction[] values = CombineFunction.values();
Builder combineFunctionMapBuilder = ImmutableMap.builder();
for (CombineFunction combineFunction : values) {
combineFunctionMapBuilder.put(combineFunction.getName(), combineFunction);
}
combineFunctionsMap = combineFunctionMapBuilder.build();
}
@Override
public Query parse(QueryParseContext parseContext) throws IOException, QueryParsingException {
XContentParser parser = parseContext.parser();
Query query = null;
Query filter = null;
float boost = 1.0f;
FiltersFunctionScoreQuery.ScoreMode scoreMode = FiltersFunctionScoreQuery.ScoreMode.Multiply;
ArrayList filterFunctions = new ArrayList<>();
Float maxBoost = null;
Float minScore = null;
String currentFieldName = null;
XContentParser.Token token;
CombineFunction combineFunction = CombineFunction.MULT;
// Either define array of functions and filters or only one function
boolean functionArrayFound = false;
boolean singleFunctionFound = false;
String singleFunctionName = null;
while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
if (token == XContentParser.Token.FIELD_NAME) {
currentFieldName = parser.currentName();
} else if ("query".equals(currentFieldName)) {
query = parseContext.parseInnerQuery();
} else if (parseContext.parseFieldMatcher().match(currentFieldName, FILTER_FIELD)) {
filter = parseContext.parseInnerFilter();
} else if ("score_mode".equals(currentFieldName) || "scoreMode".equals(currentFieldName)) {
scoreMode = parseScoreMode(parseContext, parser);
} else if ("boost_mode".equals(currentFieldName) || "boostMode".equals(currentFieldName)) {
combineFunction = parseBoostMode(parseContext, parser);
} else if ("max_boost".equals(currentFieldName) || "maxBoost".equals(currentFieldName)) {
maxBoost = parser.floatValue();
} else if ("boost".equals(currentFieldName)) {
boost = parser.floatValue();
} else if ("min_score".equals(currentFieldName) || "minScore".equals(currentFieldName)) {
minScore = parser.floatValue();
} else if ("functions".equals(currentFieldName)) {
if (singleFunctionFound) {
String errorString = "already found [" + singleFunctionName + "], now encountering [functions].";
handleMisplacedFunctionsDeclaration(errorString, singleFunctionName);
}
currentFieldName = parseFiltersAndFunctions(parseContext, parser, filterFunctions, currentFieldName);
functionArrayFound = true;
} else {
ScoreFunction scoreFunction;
if (currentFieldName.equals("weight")) {
scoreFunction = new WeightFactorFunction(parser.floatValue());
} else {
// we try to parse a score function. If there is no score
// function for the current field name,
// functionParserMapper.get() will throw an Exception.
scoreFunction = functionParserMapper.get(parseContext, currentFieldName).parse(parseContext, parser);
}
if (functionArrayFound) {
String errorString = "already found [functions] array, now encountering [" + currentFieldName + "].";
handleMisplacedFunctionsDeclaration(errorString, currentFieldName);
}
if (filterFunctions.size() > 0) {
throw new ElasticsearchParseException("failed to parse [{}] query. already found function [{}], now encountering [{}]. use [functions] array if you want to define several functions.", NAME, singleFunctionName, currentFieldName);
}
filterFunctions.add(new FiltersFunctionScoreQuery.FilterFunction(null, scoreFunction));
singleFunctionFound = true;
singleFunctionName = currentFieldName;
}
}
if (query == null && filter == null) {
query = Queries.newMatchAllQuery();
} else if (query == null && filter != null) {
query = new ConstantScoreQuery(filter);
} else if (query != null && filter != null) {
final BooleanQuery.Builder filtered = new BooleanQuery.Builder();
filtered.add(query, Occur.MUST);
filtered.add(filter, Occur.FILTER);
query = filtered.build();
}
// if all filter elements returned null, just use the query
if (filterFunctions.isEmpty() && combineFunction == null) {
return query;
}
if (maxBoost == null) {
maxBoost = Float.MAX_VALUE;
}
// handle cases where only one score function and no filter was
// provided. In this case we create a FunctionScoreQuery.
if (filterFunctions.size() == 0 || filterFunctions.size() == 1 && (filterFunctions.get(0).filter == null || Queries.isConstantMatchAllQuery(filterFunctions.get(0).filter))) {
ScoreFunction function = filterFunctions.size() == 0 ? null : filterFunctions.get(0).function;
FunctionScoreQuery theQuery = new FunctionScoreQuery(query, function, minScore);
if (combineFunction != null) {
theQuery.setCombineFunction(combineFunction);
}
theQuery.setBoost(boost);
theQuery.setMaxBoost(maxBoost);
return theQuery;
// in all other cases we create a FiltersFunctionScoreQuery.
} else {
FiltersFunctionScoreQuery functionScoreQuery = new FiltersFunctionScoreQuery(query, scoreMode,
filterFunctions.toArray(new FiltersFunctionScoreQuery.FilterFunction[filterFunctions.size()]), maxBoost, minScore);
if (combineFunction != null) {
functionScoreQuery.setCombineFunction(combineFunction);
}
functionScoreQuery.setBoost(boost);
return functionScoreQuery;
}
}
private void handleMisplacedFunctionsDeclaration(String errorString, String functionName) {
errorString = MISPLACED_FUNCTION_MESSAGE_PREFIX + errorString;
if (Arrays.asList(FactorParser.NAMES).contains(functionName)) {
errorString = errorString + MISPLACED_BOOST_FUNCTION_MESSAGE_SUFFIX;
}
throw new ElasticsearchParseException("failed to parse [{}] query. [{}]", NAME, errorString);
}
private String parseFiltersAndFunctions(QueryParseContext parseContext, XContentParser parser,
ArrayList filterFunctions, String currentFieldName) throws IOException {
XContentParser.Token token;
while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
Query filter = null;
ScoreFunction scoreFunction = null;
Float functionWeight = null;
if (token != XContentParser.Token.START_OBJECT) {
throw new QueryParsingException(parseContext, "failed to parse [{}]. malformed query, expected a [{}] while parsing functions but got a [{}] instead", XContentParser.Token.START_OBJECT, token, NAME);
} else {
while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
if (token == XContentParser.Token.FIELD_NAME) {
currentFieldName = parser.currentName();
} else if (parseContext.parseFieldMatcher().match(currentFieldName, WEIGHT_FIELD)) {
functionWeight = parser.floatValue();
} else {
if ("filter".equals(currentFieldName)) {
filter = parseContext.parseInnerFilter();
} else {
// do not need to check null here,
// functionParserMapper throws exception if parser
// non-existent
ScoreFunctionParser functionParser = functionParserMapper.get(parseContext, currentFieldName);
scoreFunction = functionParser.parse(parseContext, parser);
}
}
}
if (functionWeight != null) {
scoreFunction = new WeightFactorFunction(functionWeight, scoreFunction);
}
}
if (filter == null) {
filter = Queries.newMatchAllQuery();
}
if (scoreFunction == null) {
throw new ElasticsearchParseException("failed to parse [{}] query. an entry in functions list is missing a function.", NAME);
}
filterFunctions.add(new FiltersFunctionScoreQuery.FilterFunction(filter, scoreFunction));
}
return currentFieldName;
}
private FiltersFunctionScoreQuery.ScoreMode parseScoreMode(QueryParseContext parseContext, XContentParser parser) throws IOException {
String scoreMode = parser.text();
if ("avg".equals(scoreMode)) {
return FiltersFunctionScoreQuery.ScoreMode.Avg;
} else if ("max".equals(scoreMode)) {
return FiltersFunctionScoreQuery.ScoreMode.Max;
} else if ("min".equals(scoreMode)) {
return FiltersFunctionScoreQuery.ScoreMode.Min;
} else if ("sum".equals(scoreMode)) {
return FiltersFunctionScoreQuery.ScoreMode.Sum;
} else if ("multiply".equals(scoreMode)) {
return FiltersFunctionScoreQuery.ScoreMode.Multiply;
} else if ("first".equals(scoreMode)) {
return FiltersFunctionScoreQuery.ScoreMode.First;
} else {
throw new QueryParsingException(parseContext, "failed to parse [{}] query. illegal score_mode [{}]", NAME, scoreMode);
}
}
private CombineFunction parseBoostMode(QueryParseContext parseContext, XContentParser parser) throws IOException {
String boostMode = parser.text();
CombineFunction cf = combineFunctionsMap.get(boostMode);
if (cf == null) {
throw new QueryParsingException(parseContext, "failed to parse [{}] query. illegal boost_mode [{}]", NAME, boostMode);
}
return cf;
}
}