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Elasticsearch - Open Source, Distributed, RESTful Search Engine
/*
* Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
* or more contributor license agreements. Licensed under the Elastic License
* 2.0 and the Server Side Public License, v 1; you may not use this file except
* in compliance with, at your election, the Elastic License 2.0 or the Server
* Side Public License, v 1.
*/
package org.elasticsearch.index.query;
import org.apache.lucene.search.BoostQuery;
import org.apache.lucene.search.MatchNoDocsQuery;
import org.apache.lucene.search.NamedMatches;
import org.apache.lucene.search.Query;
import org.apache.lucene.util.BytesRef;
import org.elasticsearch.common.ParsingException;
import org.elasticsearch.common.Strings;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.common.lucene.BytesRefs;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.xcontent.SuggestingErrorOnUnknown;
import org.elasticsearch.xcontent.AbstractObjectParser;
import org.elasticsearch.xcontent.FilterXContentParser;
import org.elasticsearch.xcontent.FilterXContentParserWrapper;
import org.elasticsearch.xcontent.NamedObjectNotFoundException;
import org.elasticsearch.xcontent.ParseField;
import org.elasticsearch.xcontent.XContentBuilder;
import org.elasticsearch.xcontent.XContentLocation;
import org.elasticsearch.xcontent.XContentParser;
import java.io.IOException;
import java.math.BigInteger;
import java.nio.CharBuffer;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Objects;
import java.util.function.Consumer;
import static org.elasticsearch.search.SearchModule.INDICES_MAX_NESTED_DEPTH_SETTING;
/**
* Base class for all classes producing lucene queries.
* Supports conversion to BytesReference and creation of lucene Query objects.
*/
public abstract class AbstractQueryBuilder> implements QueryBuilder {
/** Default for boost to apply to resulting Lucene query. Defaults to 1.0*/
public static final float DEFAULT_BOOST = 1.0f;
public static final ParseField NAME_FIELD = new ParseField("_name");
public static final ParseField BOOST_FIELD = new ParseField("boost");
// We set the default value for tests that don't go through SearchModule
private static int maxNestedDepth = INDICES_MAX_NESTED_DEPTH_SETTING.getDefault(Settings.EMPTY);
protected String queryName;
protected float boost = DEFAULT_BOOST;
protected AbstractQueryBuilder() {
}
@SuppressWarnings("this-escape")
protected AbstractQueryBuilder(StreamInput in) throws IOException {
boost = in.readFloat();
checkNegativeBoost(boost);
queryName = in.readOptionalString();
}
@Override
public final void writeTo(StreamOutput out) throws IOException {
out.writeFloat(boost);
out.writeOptionalString(queryName);
doWriteTo(out);
}
protected abstract void doWriteTo(StreamOutput out) throws IOException;
@Override
public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
builder.startObject();
doXContent(builder, params);
builder.endObject();
return builder;
}
protected abstract void doXContent(XContentBuilder builder, Params params) throws IOException;
/**
* Add {@code boost} and {@code query_name} to the builder.
* @deprecated use {@link #boostAndQueryNameToXContent}
*/
@Deprecated
protected final void printBoostAndQueryName(XContentBuilder builder) throws IOException {
builder.field(BOOST_FIELD.getPreferredName(), boost);
if (queryName != null) {
builder.field(NAME_FIELD.getPreferredName(), queryName);
}
}
/**
* Add {@code boost} and {@code query_name} to the builder.
*/
protected final void boostAndQueryNameToXContent(XContentBuilder builder) throws IOException {
if (boost != DEFAULT_BOOST) {
builder.field(BOOST_FIELD.getPreferredName(), boost);
}
if (queryName != null) {
builder.field(NAME_FIELD.getPreferredName(), queryName);
}
}
@Override
public final Query toQuery(SearchExecutionContext context) throws IOException {
Query query = doToQuery(context);
if (query != null) {
if (boost != DEFAULT_BOOST) {
if (query instanceof MatchNoDocsQuery == false) {
query = new BoostQuery(query, boost);
}
}
if (queryName != null) {
if (context.rewriteToNamedQuery()) {
query = NamedMatches.wrapQuery(queryName, query);
}
context.addNamedQuery(queryName, query);
}
}
return query;
}
protected abstract Query doToQuery(SearchExecutionContext context) throws IOException;
/**
* Sets the query name for the query.
*/
@SuppressWarnings("unchecked")
@Override
public final QB queryName(String queryName) {
this.queryName = queryName;
return (QB) this;
}
/**
* Returns the query name for the query.
*/
@Override
public final String queryName() {
return queryName;
}
/**
* Returns the boost for this query.
*/
@Override
public final float boost() {
return this.boost;
}
protected final void checkNegativeBoost(float boost) {
if (Float.compare(boost, 0f) < 0) {
throw new IllegalArgumentException(
"negative [boost] are not allowed in [" + toString() + "], use a value between 0 and 1 to deboost"
);
}
}
/**
* Sets the boost for this query. Documents matching this query will (in addition to the normal
* weightings) have their score multiplied by the boost provided.
*/
@SuppressWarnings("unchecked")
@Override
public final QB boost(float boost) {
checkNegativeBoost(boost);
this.boost = boost;
return (QB) this;
}
protected final QueryValidationException addValidationError(String validationError, QueryValidationException validationException) {
return QueryValidationException.addValidationError(getName(), validationError, validationException);
}
@Override
public final boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null || getClass() != obj.getClass()) {
return false;
}
@SuppressWarnings("unchecked")
QB other = (QB) obj;
return Objects.equals(queryName, other.queryName) && Objects.equals(boost, other.boost) && doEquals(other);
}
/**
* Indicates whether some other {@link QueryBuilder} object of the same type is "equal to" this one.
*/
protected abstract boolean doEquals(QB other);
@Override
public final int hashCode() {
return Objects.hash(getClass(), queryName, boost, doHashCode());
}
protected abstract int doHashCode();
/**
* This helper method checks if the object passed in is a string or {@link CharBuffer},
* if so it converts it to a {@link BytesRef}.
* @param obj the input object
* @return the same input object or a {@link BytesRef} representation if input was of type string
*/
static Object maybeConvertToBytesRef(Object obj) {
if (obj instanceof String) {
return BytesRefs.checkIndexableLength(BytesRefs.toBytesRef(obj));
} else if (obj instanceof CharBuffer) {
return BytesRefs.checkIndexableLength(new BytesRef((CharBuffer) obj));
} else if (obj instanceof BigInteger) {
return BytesRefs.toBytesRef(obj);
}
return obj;
}
/**
* This helper method checks if the object passed in is a {@link BytesRef} or {@link CharBuffer},
* if so it converts it to a utf8 string.
* @param obj the input object
* @return the same input object or a utf8 string if input was of type {@link BytesRef} or {@link CharBuffer}
*/
static Object maybeConvertToString(Object obj) {
if (obj instanceof BytesRef) {
return ((BytesRef) obj).utf8ToString();
} else if (obj instanceof CharBuffer) {
return new BytesRef((CharBuffer) obj).utf8ToString();
}
return obj;
}
/**
* Helper method to convert collection of {@link QueryBuilder} instances to lucene
* {@link Query} instances. {@link QueryBuilder} that return {@code null} calling
* their {@link QueryBuilder#toQuery(SearchExecutionContext)} method are not added to the
* resulting collection.
*/
static Collection toQueries(Collection queryBuilders, SearchExecutionContext context) throws QueryShardException,
IOException {
List queries = new ArrayList<>(queryBuilders.size());
for (QueryBuilder queryBuilder : queryBuilders) {
Query query = queryBuilder.rewrite(context).toQuery(context);
if (query != null) {
queries.add(query);
}
}
return queries;
}
@Override
public String getName() {
// default impl returns the same as writeable name, but we keep the distinction between the two just to make sure
return getWriteableName();
}
protected static void writeQueries(StreamOutput out, List queries) throws IOException {
out.writeVInt(queries.size());
for (QueryBuilder query : queries) {
out.writeNamedWriteable(query);
}
}
protected static List readQueries(StreamInput in) throws IOException {
return in.readNamedWriteableCollectionAsList(QueryBuilder.class);
}
@Override
public final QueryBuilder rewrite(QueryRewriteContext queryRewriteContext) throws IOException {
QueryBuilder rewritten = doRewrite(queryRewriteContext);
if (rewritten == this) {
return rewritten;
}
if (queryName() != null && rewritten.queryName() == null) { // we inherit the name
rewritten.queryName(queryName());
}
if (boost() != DEFAULT_BOOST && rewritten.boost() == DEFAULT_BOOST) {
rewritten.boost(boost());
}
return rewritten;
}
protected QueryBuilder doRewrite(QueryRewriteContext queryRewriteContext) throws IOException {
// NOTE: sometimes rewrites are attempted after calling `QueryRewriteContext#convertToSearchExecutionContext`
// which returns `null` in the default implementation.
if (queryRewriteContext == null) {
return this;
}
final InnerHitsRewriteContext ihrc = queryRewriteContext.convertToInnerHitsRewriteContext();
if (ihrc != null) {
return doInnerHitsRewrite(ihrc);
}
final CoordinatorRewriteContext crc = queryRewriteContext.convertToCoordinatorRewriteContext();
if (crc != null) {
return doCoordinatorRewrite(crc);
}
final SearchExecutionContext sec = queryRewriteContext.convertToSearchExecutionContext();
if (sec != null) {
return doSearchRewrite(sec);
}
final QueryRewriteContext context = queryRewriteContext.convertToIndexMetadataContext();
if (context != null) {
return doIndexMetadataRewrite(context);
}
return this;
}
/**
* @param coordinatorRewriteContext A {@link QueryRewriteContext} that enables limited rewrite capabilities
* happening on the coordinator node before execution moves to the data node.
* @return A {@link QueryBuilder} representing the rewritten query which could be executed without going to
* the date node.
*/
protected QueryBuilder doCoordinatorRewrite(final CoordinatorRewriteContext coordinatorRewriteContext) {
return this;
}
/**
* @param searchExecutionContext A {@link QueryRewriteContext} that enables full rewrite capabilities
* happening on the data node with all information available for rewriting.
* @return A {@link QueryBuilder} representing the rewritten query.
*/
protected QueryBuilder doSearchRewrite(final SearchExecutionContext searchExecutionContext) throws IOException {
return doIndexMetadataRewrite(searchExecutionContext);
}
/**
* Optional rewrite logic that only needs access to index level metadata and services (e.g. index settings and mappings)
* on the data node, but not the shard / Lucene index.
* The can_match phase can use this logic to early terminate a search without doing any search related i/o.
*
* @param context an {@link QueryRewriteContext} instance that has access the mappings and other index metadata
* @return A {@link QueryBuilder} representing the rewritten query, that could be used to determine whether this query yields result.
*/
protected QueryBuilder doIndexMetadataRewrite(final QueryRewriteContext context) throws IOException {
return this;
}
/**
* Optional rewrite logic that allows for optimization for extracting inner hits
* @param context an {@link InnerHitsRewriteContext} instance
* @return A {@link QueryBuilder} representing the rewritten query optimized for inner hit extraction
* @throws IOException if an error occurs while rewriting the query
*/
protected QueryBuilder doInnerHitsRewrite(final InnerHitsRewriteContext context) throws IOException {
return this;
}
/**
* For internal usage only!
*
* Extracts the inner hits from the query tree.
* While it extracts inner hits, child inner hits are inlined into the inner hit builder they belong to.
*/
protected void extractInnerHitBuilders(Map innerHits) {}
/**
* Parses and returns a query (excluding the query field that wraps it). To be called by API that support
* user provided queries. Note that the returned query may hold inner queries, and so on. Calling this method
* will initialize the tracking of nested depth to make sure that there's a limit to the number of queries
* that can be nested within one another (see {@link org.elasticsearch.search.SearchModule#INDICES_MAX_NESTED_DEPTH_SETTING}.
* This variant of the method does not support collecting statistics about queries usage.
*/
public static QueryBuilder parseTopLevelQuery(XContentParser parser) throws IOException {
return parseTopLevelQuery(parser, queryName -> {});
}
/**
* Parses and returns a query (excluding the query field that wraps it). To be called by API that support
* user provided queries. Note that the returned query may hold inner queries, and so on. Calling this method
* will initialize the tracking of nested depth to make sure that there's a limit to the number of queries
* that can be nested within one another (see {@link org.elasticsearch.search.SearchModule#INDICES_MAX_NESTED_DEPTH_SETTING}.
* The method accepts a string consumer that will be provided with each query type used in the parsed content, to be used
* for instance to collect statistics about queries usage.
*/
public static QueryBuilder parseTopLevelQuery(XContentParser parser, Consumer queryNameConsumer) throws IOException {
FilterXContentParser parserWrapper = new FilterXContentParserWrapper(parser) {
int nestedDepth;
@Override
public T namedObject(Class categoryClass, String name, Object context) throws IOException {
if (categoryClass.equals(QueryBuilder.class)) {
nestedDepth++;
if (nestedDepth > maxNestedDepth) {
throw new IllegalArgumentException(
"The nested depth of the query exceeds the maximum nested depth for queries set in ["
+ INDICES_MAX_NESTED_DEPTH_SETTING.getKey()
+ "]"
);
}
}
T namedObject = getXContentRegistry().parseNamedObject(categoryClass, name, this, context);
if (categoryClass.equals(QueryBuilder.class)) {
queryNameConsumer.accept(name);
nestedDepth--;
}
return namedObject;
}
};
return parseInnerQueryBuilder(parserWrapper);
}
/**
* Parses an inner query. To be called by query implementations that support inner queries.
*/
protected static QueryBuilder parseInnerQueryBuilder(XContentParser parser) throws IOException {
if (parser.currentToken() != XContentParser.Token.START_OBJECT) {
if (parser.nextToken() != XContentParser.Token.START_OBJECT) {
throw new ParsingException(parser.getTokenLocation(), "[_na] query malformed, must start with start_object");
}
}
if (parser.nextToken() == XContentParser.Token.END_OBJECT) {
// we encountered '{}' for a query clause, it used to be supported, deprecated in 5.0 and removed in 6.0
throw new IllegalArgumentException("query malformed, empty clause found at [" + parser.getTokenLocation() + "]");
}
if (parser.currentToken() != XContentParser.Token.FIELD_NAME) {
throw new ParsingException(parser.getTokenLocation(), "[_na] query malformed, no field after start_object");
}
String queryName = parser.currentName();
// move to the next START_OBJECT
if (parser.nextToken() != XContentParser.Token.START_OBJECT) {
throw new ParsingException(parser.getTokenLocation(), "[" + queryName + "] query malformed, no start_object after query name");
}
QueryBuilder result;
try {
result = parser.namedObject(QueryBuilder.class, queryName, null);
} catch (NamedObjectNotFoundException e) {
String message = String.format(
Locale.ROOT,
"unknown query [%s]%s",
queryName,
SuggestingErrorOnUnknown.suggest(queryName, e.getCandidates())
);
throw new ParsingException(new XContentLocation(e.getLineNumber(), e.getColumnNumber()), message, e);
}
// end_object of the specific query (e.g. match, multi_match etc.) element
if (parser.currentToken() != XContentParser.Token.END_OBJECT) {
throw new ParsingException(
parser.getTokenLocation(),
"[" + queryName + "] malformed query, expected [END_OBJECT] but found [" + parser.currentToken() + "]"
);
}
// end_object of the query object
if (parser.nextToken() != XContentParser.Token.END_OBJECT) {
throw new ParsingException(
parser.getTokenLocation(),
"[" + queryName + "] malformed query, expected [END_OBJECT] but found [" + parser.currentToken() + "]"
);
}
return result;
}
// Like Objects.requireNotNull(...) but instead throws a IllegalArgumentException
protected static T requireValue(T value, String message) {
if (value == null) {
throw new IllegalArgumentException(message);
}
return value;
}
protected static void throwParsingExceptionOnMultipleFields(
String queryName,
XContentLocation contentLocation,
String processedFieldName,
String currentFieldName
) {
if (processedFieldName != null) {
throw new ParsingException(
contentLocation,
"["
+ queryName
+ "] query doesn't support multiple fields, found ["
+ processedFieldName
+ "] and ["
+ currentFieldName
+ "]"
);
}
}
/**
* Adds {@code boost} and {@code query_name} parsing to the
* {@link AbstractObjectParser} passed in. All query builders except
* {@link MatchAllQueryBuilder} and {@link MatchNoneQueryBuilder} support these fields so they
* should use this method.
*/
protected static void declareStandardFields(AbstractObjectParser parser) {
parser.declareFloat(QueryBuilder::boost, AbstractQueryBuilder.BOOST_FIELD);
parser.declareString(QueryBuilder::queryName, AbstractQueryBuilder.NAME_FIELD);
}
/**
* Set the maximum nested depth of bool queries.
* Default value is 20.
*/
public static void setMaxNestedDepth(int maxNestedDepth) {
if (maxNestedDepth < 1) {
throw new IllegalArgumentException("maxNestedDepth must be >= 1");
}
AbstractQueryBuilder.maxNestedDepth = maxNestedDepth;
}
public static int getMaxNestedDepth() {
return maxNestedDepth;
}
@Override
public final String toString() {
return Strings.toString(this, true, true);
}
}