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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.search.collapse;
import org.elasticsearch.common.ParseField;
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.io.stream.Writeable;
import org.elasticsearch.common.xcontent.ObjectParser;
import org.elasticsearch.common.xcontent.ToXContent;
import org.elasticsearch.common.xcontent.ToXContentObject;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.common.xcontent.XContentParser;
import org.elasticsearch.index.mapper.MappedFieldType;
import org.elasticsearch.index.query.InnerHitBuilder;
import org.elasticsearch.index.query.QueryShardContext;
import org.elasticsearch.index.mapper.MappedFieldType.CollapseType;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Objects;
/**
* A builder that enables field collapsing on search request.
*/
public class CollapseBuilder implements Writeable, ToXContentObject {
public static final ParseField FIELD_FIELD = new ParseField("field");
public static final ParseField INNER_HITS_FIELD = new ParseField("inner_hits");
public static final ParseField MAX_CONCURRENT_GROUP_REQUESTS_FIELD = new ParseField("max_concurrent_group_searches");
private static final ObjectParser PARSER =
new ObjectParser<>("collapse", CollapseBuilder::new);
static {
PARSER.declareString(CollapseBuilder::setField, FIELD_FIELD);
PARSER.declareInt(CollapseBuilder::setMaxConcurrentGroupRequests, MAX_CONCURRENT_GROUP_REQUESTS_FIELD);
PARSER.declareField((parser, builder, context) -> {
XContentParser.Token currentToken = parser.currentToken();
if (currentToken == XContentParser.Token.START_OBJECT) {
builder.setInnerHits(InnerHitBuilder.fromXContent(parser));
} else if (currentToken == XContentParser.Token.START_ARRAY) {
List innerHitBuilders = new ArrayList<>();
for (currentToken = parser.nextToken(); currentToken != XContentParser.Token.END_ARRAY; currentToken = parser.nextToken()) {
if (currentToken == XContentParser.Token.START_OBJECT) {
innerHitBuilders.add(InnerHitBuilder.fromXContent(parser));
} else {
throw new ParsingException(parser.getTokenLocation(), "Invalid token in inner_hits array");
}
}
builder.setInnerHits(innerHitBuilders);
}
}, INNER_HITS_FIELD, ObjectParser.ValueType.OBJECT_ARRAY);
}
private String field;
private List innerHits = Collections.emptyList();
private int maxConcurrentGroupRequests = 0;
private CollapseBuilder() {}
/**
* Public constructor
* @param field The name of the field to collapse on
*/
public CollapseBuilder(String field) {
Objects.requireNonNull(field, "field must be non-null");
this.field = field;
}
public CollapseBuilder(StreamInput in) throws IOException {
this.field = in.readString();
this.maxConcurrentGroupRequests = in.readVInt();
this.innerHits = in.readList(InnerHitBuilder::new);
}
@Override
public void writeTo(StreamOutput out) throws IOException {
out.writeString(field);
out.writeVInt(maxConcurrentGroupRequests);
out.writeList(innerHits);
}
public static CollapseBuilder fromXContent(XContentParser parser) {
return PARSER.apply(parser, null);
}
// for object parser only
private CollapseBuilder setField(String field) {
if (Strings.isEmpty(field)) {
throw new IllegalArgumentException("field name is null or empty");
}
this.field = field;
return this;
}
public CollapseBuilder setInnerHits(InnerHitBuilder innerHit) {
this.innerHits = Collections.singletonList(innerHit);
return this;
}
public CollapseBuilder setInnerHits(List innerHits) {
this.innerHits = innerHits;
return this;
}
public CollapseBuilder setMaxConcurrentGroupRequests(int num) {
if (num < 1) {
throw new IllegalArgumentException("maxConcurrentGroupRequests` must be positive");
}
this.maxConcurrentGroupRequests = num;
return this;
}
/**
* The name of the field to collapse against
*/
public String getField() {
return this.field;
}
/**
* The inner hit options to expand the collapsed results
*/
public List getInnerHits() {
return this.innerHits;
}
/**
* Returns the amount of group requests that are allowed to be ran concurrently in the inner_hits phase.
*/
public int getMaxConcurrentGroupRequests() {
return maxConcurrentGroupRequests;
}
@Override
public XContentBuilder toXContent(XContentBuilder builder, ToXContent.Params params) throws IOException {
builder.startObject();
innerToXContent(builder);
builder.endObject();
return builder;
}
private void innerToXContent(XContentBuilder builder) throws IOException {
builder.field(FIELD_FIELD.getPreferredName(), field);
if (maxConcurrentGroupRequests > 0) {
builder.field(MAX_CONCURRENT_GROUP_REQUESTS_FIELD.getPreferredName(), maxConcurrentGroupRequests);
}
if (innerHits.isEmpty() == false) {
if (innerHits.size() == 1) {
builder.field(INNER_HITS_FIELD.getPreferredName(), innerHits.get(0));
} else {
builder.startArray(INNER_HITS_FIELD.getPreferredName());
for (InnerHitBuilder innerHit : innerHits) {
innerHit.toXContent(builder, ToXContent.EMPTY_PARAMS);
}
builder.endArray();
}
}
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
CollapseBuilder that = (CollapseBuilder) o;
if (maxConcurrentGroupRequests != that.maxConcurrentGroupRequests) return false;
if (!field.equals(that.field)) return false;
return Objects.equals(innerHits, that.innerHits);
}
@Override
public int hashCode() {
int result = Objects.hash(field, innerHits);
result = 31 * result + maxConcurrentGroupRequests;
return result;
}
public CollapseContext build(QueryShardContext queryShardContext) {
MappedFieldType fieldType = queryShardContext.getFieldType(field);
if (fieldType == null) {
throw new IllegalArgumentException("no mapping found for `" + field + "` in order to collapse on");
}
if (fieldType.collapseType() == CollapseType.NONE) {
throw new IllegalArgumentException("collapse is not supported for the field [" + fieldType.name() +
"] of the type [" + fieldType.typeName() + "]");
}
if (fieldType.hasDocValues() == false) {
throw new IllegalArgumentException("cannot collapse on field `" + field + "` without `doc_values`");
}
if (fieldType.isSearchable() == false && (innerHits != null && !innerHits.isEmpty())) {
throw new IllegalArgumentException("cannot expand `inner_hits` for collapse field `"
+ field + "`, " + "only indexed field can retrieve `inner_hits`");
}
return new CollapseContext(field, fieldType, innerHits);
}
}