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/*
* 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.queries.spans.SpanNearQuery;
import org.apache.lucene.queries.spans.SpanQuery;
import org.apache.lucene.search.Query;
import org.elasticsearch.TransportVersion;
import org.elasticsearch.TransportVersions;
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.index.mapper.MappedFieldType;
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.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Objects;
import static org.elasticsearch.index.query.SpanQueryBuilder.SpanQueryBuilderUtil.checkNoBoost;
/**
* Matches spans which are near one another. One can specify slop, the maximum number
* of intervening unmatched positions, as well as whether matches are required to be in-order.
* The span near query maps to Lucene {@link SpanNearQuery}.
*/
public class SpanNearQueryBuilder extends AbstractQueryBuilder implements SpanQueryBuilder {
public static final String NAME = "span_near";
/** Default for flag controlling whether matches are required to be in-order */
public static boolean DEFAULT_IN_ORDER = true;
/** Default slop value, this is the same that lucene {@link SpanNearQuery} uses if no slop is provided */
public static int DEFAULT_SLOP = 0;
private static final ParseField SLOP_FIELD = new ParseField("slop");
private static final ParseField CLAUSES_FIELD = new ParseField("clauses");
private static final ParseField IN_ORDER_FIELD = new ParseField("in_order");
private final List clauses = new ArrayList<>();
private final int slop;
private boolean inOrder = DEFAULT_IN_ORDER;
/**
* @param initialClause an initial span query clause
* @param slop controls the maximum number of intervening unmatched positions permitted
*/
public SpanNearQueryBuilder(SpanQueryBuilder initialClause, int slop) {
if (initialClause == null) {
throw new IllegalArgumentException("[" + NAME + "] must include at least one clause");
}
this.clauses.add(initialClause);
this.slop = slop;
}
/**
* Read from a stream.
*/
public SpanNearQueryBuilder(StreamInput in) throws IOException {
super(in);
for (QueryBuilder clause : readQueries(in)) {
this.clauses.add((SpanQueryBuilder) clause);
}
slop = in.readVInt();
inOrder = in.readBoolean();
}
@Override
protected void doWriteTo(StreamOutput out) throws IOException {
writeQueries(out, clauses);
out.writeVInt(slop);
out.writeBoolean(inOrder);
}
/**
* @return the maximum number of intervening unmatched positions permitted
*/
public int slop() {
return this.slop;
}
/**
* Add a span clause to the current list of clauses
*/
public SpanNearQueryBuilder addClause(SpanQueryBuilder clause) {
if (clause == null) {
throw new IllegalArgumentException("[" + NAME + "] clauses cannot be null");
}
clauses.add(clause);
return this;
}
/**
* @return the {@link SpanQueryBuilder} clauses that were set for this query
*/
public List clauses() {
return Collections.unmodifiableList(this.clauses);
}
/**
* When inOrder is true, the spans from each clause
* must be in the same order as in clauses and must be non-overlapping.
* Defaults to true
*/
public SpanNearQueryBuilder inOrder(boolean inOrder) {
this.inOrder = inOrder;
return this;
}
/**
* @see SpanNearQueryBuilder#inOrder(boolean)
*/
public boolean inOrder() {
return this.inOrder;
}
@Override
protected void doXContent(XContentBuilder builder, Params params) throws IOException {
builder.startObject(NAME);
builder.startArray(CLAUSES_FIELD.getPreferredName());
for (SpanQueryBuilder clause : clauses) {
clause.toXContent(builder, params);
}
builder.endArray();
builder.field(SLOP_FIELD.getPreferredName(), slop);
builder.field(IN_ORDER_FIELD.getPreferredName(), inOrder);
boostAndQueryNameToXContent(builder);
builder.endObject();
}
public static SpanNearQueryBuilder fromXContent(XContentParser parser) throws IOException {
float boost = AbstractQueryBuilder.DEFAULT_BOOST;
int slop = DEFAULT_SLOP;
boolean inOrder = DEFAULT_IN_ORDER;
String queryName = null;
List clauses = new ArrayList<>();
String currentFieldName = null;
XContentParser.Token token;
while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
if (token == XContentParser.Token.FIELD_NAME) {
currentFieldName = parser.currentName();
} else if (token == XContentParser.Token.START_ARRAY) {
if (CLAUSES_FIELD.match(currentFieldName, parser.getDeprecationHandler())) {
while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
QueryBuilder query = parseInnerQueryBuilder(parser);
if (query instanceof SpanQueryBuilder == false) {
throw new ParsingException(parser.getTokenLocation(), "span_near [clauses] must be of type span query");
}
final SpanQueryBuilder clause = (SpanQueryBuilder) query;
checkNoBoost(NAME, currentFieldName, parser, clause);
clauses.add(clause);
}
} else {
throw new ParsingException(parser.getTokenLocation(), "[span_near] query does not support [" + currentFieldName + "]");
}
} else if (token.isValue()) {
if (IN_ORDER_FIELD.match(currentFieldName, parser.getDeprecationHandler())) {
inOrder = parser.booleanValue();
} else if (SLOP_FIELD.match(currentFieldName, parser.getDeprecationHandler())) {
slop = parser.intValue();
} else if (AbstractQueryBuilder.BOOST_FIELD.match(currentFieldName, parser.getDeprecationHandler())) {
boost = parser.floatValue();
} else if (AbstractQueryBuilder.NAME_FIELD.match(currentFieldName, parser.getDeprecationHandler())) {
queryName = parser.text();
} else {
throw new ParsingException(parser.getTokenLocation(), "[span_near] query does not support [" + currentFieldName + "]");
}
} else {
throw new ParsingException(parser.getTokenLocation(), "[span_near] query does not support [" + currentFieldName + "]");
}
}
if (clauses.isEmpty()) {
throw new ParsingException(parser.getTokenLocation(), "span_near must include [clauses]");
}
SpanNearQueryBuilder queryBuilder = new SpanNearQueryBuilder(clauses.get(0), slop);
for (int i = 1; i < clauses.size(); i++) {
queryBuilder.addClause(clauses.get(i));
}
queryBuilder.inOrder(inOrder);
queryBuilder.boost(boost);
queryBuilder.queryName(queryName);
return queryBuilder;
}
@Override
protected Query doToQuery(SearchExecutionContext context) throws IOException {
SpanQueryBuilder queryBuilder = clauses.get(0);
boolean isGap = queryBuilder instanceof SpanGapQueryBuilder;
Query query = null;
if (isGap == false) {
query = queryBuilder.toQuery(context);
assert query instanceof SpanQuery;
}
if (clauses.size() == 1) {
assert isGap == false;
return query;
}
String spanNearFieldName = null;
if (isGap) {
String fieldName = ((SpanGapQueryBuilder) queryBuilder).fieldName();
spanNearFieldName = queryFieldName(context, fieldName);
} else {
spanNearFieldName = ((SpanQuery) query).getField();
}
SpanNearQuery.Builder builder = new SpanNearQuery.Builder(spanNearFieldName, inOrder);
builder.setSlop(slop);
/*
* Lucene SpanNearQuery throws exceptions for certain use cases like adding gap to a
* unordered SpanNearQuery. Should ES have the same checks or wrap those thrown exceptions?
*/
if (isGap) {
int gap = ((SpanGapQueryBuilder) queryBuilder).width();
builder.addGap(gap);
} else {
builder.addClause((SpanQuery) query);
}
for (int i = 1; i < clauses.size(); i++) {
queryBuilder = clauses.get(i);
isGap = queryBuilder instanceof SpanGapQueryBuilder;
if (isGap) {
String fieldName = ((SpanGapQueryBuilder) queryBuilder).fieldName();
String spanGapFieldName = queryFieldName(context, fieldName);
if (spanNearFieldName.equals(spanGapFieldName) == false) {
throw new IllegalArgumentException("[span_near] clauses must have same field");
}
int gap = ((SpanGapQueryBuilder) queryBuilder).width();
builder.addGap(gap);
} else {
query = clauses.get(i).toQuery(context);
assert query instanceof SpanQuery;
builder.addClause((SpanQuery) query);
}
}
return builder.build();
}
private static String queryFieldName(SearchExecutionContext context, String fieldName) {
MappedFieldType fieldType = context.getFieldType(fieldName);
return fieldType != null ? fieldType.name() : fieldName;
}
@Override
protected int doHashCode() {
return Objects.hash(clauses, slop, inOrder);
}
@Override
protected boolean doEquals(SpanNearQueryBuilder other) {
return Objects.equals(clauses, other.clauses) && Objects.equals(slop, other.slop) && Objects.equals(inOrder, other.inOrder);
}
@Override
public String getWriteableName() {
return NAME;
}
@Override
public TransportVersion getMinimalSupportedVersion() {
return TransportVersions.ZERO;
}
/**
* SpanGapQueryBuilder enables gaps in a SpanNearQuery.
* Since, SpanGapQuery is private to SpanNearQuery, SpanGapQueryBuilder cannot
* be used to generate a Query (SpanGapQuery) like another QueryBuilder.
* Instead, it just identifies a span_gap clause so that SpanNearQuery.addGap(int)
* can be invoked for it.
* This QueryBuilder is only applicable as a clause in SpanGapQueryBuilder but
* yet to enforce this restriction.
*/
public static class SpanGapQueryBuilder implements SpanQueryBuilder {
public static final String NAME = "span_gap";
/** Name of field to match against. */
private final String fieldName;
/** Width of the gap introduced. */
private final int width;
/**
* Constructs a new SpanGapQueryBuilder term query.
*
* @param fieldName The name of the field
* @param width The width of the gap introduced
*/
public SpanGapQueryBuilder(String fieldName, int width) {
if (Strings.isEmpty(fieldName)) {
throw new IllegalArgumentException("[span_gap] field name is null or empty");
}
// lucene has not coded any restriction on value of width.
// to-do : find if theoretically it makes sense to apply restrictions.
this.fieldName = fieldName;
this.width = width;
}
/**
* Read from a stream.
*/
public SpanGapQueryBuilder(StreamInput in) throws IOException {
fieldName = in.readString();
width = in.readInt();
}
/**
* @return fieldName The name of the field
*/
public String fieldName() {
return fieldName;
}
/**
* @return width The width of the gap introduced
*/
public int width() {
return width;
}
@Override
public Query toQuery(SearchExecutionContext context) throws IOException {
throw new UnsupportedOperationException();
}
@Override
public String queryName() {
throw new UnsupportedOperationException();
}
@Override
public QueryBuilder queryName(String queryName) {
throw new UnsupportedOperationException();
}
@Override
public float boost() {
throw new UnsupportedOperationException();
}
@Override
public QueryBuilder boost(float boost) {
throw new UnsupportedOperationException();
}
@Override
public String getName() {
return NAME;
}
@Override
public String getWriteableName() {
return NAME;
}
@Override
public TransportVersion getMinimalSupportedVersion() {
return TransportVersions.ZERO;
}
@Override
public final void writeTo(StreamOutput out) throws IOException {
out.writeString(fieldName);
out.writeInt(width);
}
@Override
public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
builder.startObject();
builder.startObject(getName());
builder.field(fieldName, width);
builder.endObject();
builder.endObject();
return builder;
}
public static SpanGapQueryBuilder fromXContent(XContentParser parser) throws IOException {
String fieldName = null;
int width = 0;
String currentFieldName = null;
XContentParser.Token token;
while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
if (token == XContentParser.Token.FIELD_NAME) {
currentFieldName = parser.currentName();
throwParsingExceptionOnMultipleFields(NAME, parser.getTokenLocation(), fieldName, currentFieldName);
fieldName = currentFieldName;
} else if (token.isValue()) {
width = parser.intValue();
}
}
SpanGapQueryBuilder result = new SpanGapQueryBuilder(fieldName, width);
return result;
}
@Override
public final boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null || getClass() != obj.getClass()) {
return false;
}
SpanGapQueryBuilder other = (SpanGapQueryBuilder) obj;
return Objects.equals(fieldName, other.fieldName) && Objects.equals(width, other.width);
}
@Override
public final int hashCode() {
return Objects.hash(getClass(), fieldName, width);
}
@Override
public final String toString() {
return Strings.toString(this, true, true);
}
// copied from AbstractQueryBuilder
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
+ "]"
);
}
}
}
}