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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.search.collapse;
import org.apache.lucene.index.IndexOptions;
import org.elasticsearch.Version;
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.KeywordFieldMapper;
import org.elasticsearch.index.mapper.MappedFieldType;
import org.elasticsearch.index.mapper.NumberFieldMapper;
import org.elasticsearch.index.query.InnerHitBuilder;
import org.elasticsearch.search.SearchContextException;
import org.elasticsearch.search.internal.SearchContext;
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();
if (in.getVersion().onOrAfter(Version.V_5_5_0)) {
this.innerHits = in.readList(InnerHitBuilder::new);
} else {
InnerHitBuilder innerHitBuilder = in.readOptionalWriteable(InnerHitBuilder::new);
if (innerHitBuilder != null) {
this.innerHits = Collections.singletonList(innerHitBuilder);
} else {
this.innerHits = Collections.emptyList();
}
}
}
@Override
public void writeTo(StreamOutput out) throws IOException {
out.writeString(field);
out.writeVInt(maxConcurrentGroupRequests);
if (out.getVersion().onOrAfter(Version.V_5_5_0)) {
out.writeList(innerHits);
} else {
boolean hasInnerHit = innerHits.isEmpty() == false;
out.writeBoolean(hasInnerHit);
if (hasInnerHit) {
innerHits.get(0).writeToCollapseBWC(out);
}
}
}
public static CollapseBuilder fromXContent(XContentParser parser) throws IOException {
CollapseBuilder builder = PARSER.parse(parser, new CollapseBuilder(), null);
return builder;
}
// 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(SearchContext context) {
if (context.scrollContext() != null) {
throw new SearchContextException(context, "cannot use `collapse` in a scroll context");
}
if (context.searchAfter() != null) {
throw new SearchContextException(context, "cannot use `collapse` in conjunction with `search_after`");
}
if (context.rescore() != null && context.rescore().isEmpty() == false) {
throw new SearchContextException(context, "cannot use `collapse` in conjunction with `rescore`");
}
MappedFieldType fieldType = context.getQueryShardContext().fieldMapper(field);
if (fieldType == null) {
throw new SearchContextException(context, "no mapping found for `" + field + "` in order to collapse on");
}
if (fieldType instanceof KeywordFieldMapper.KeywordFieldType == false &&
fieldType instanceof NumberFieldMapper.NumberFieldType == false) {
throw new SearchContextException(context, "unknown type for collapse field `" + field +
"`, only keywords and numbers are accepted");
}
if (fieldType.hasDocValues() == false) {
throw new SearchContextException(context, "cannot collapse on field `" + field + "` without `doc_values`");
}
if (fieldType.indexOptions() == IndexOptions.NONE && (innerHits != null && !innerHits.isEmpty())) {
throw new SearchContextException(context, "cannot expand `inner_hits` for collapse field `"
+ field + "`, " + "only indexed field can retrieve `inner_hits`");
}
return new CollapseContext(fieldType, innerHits);
}
}