/*
* 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.sort;
import org.apache.lucene.search.SortField;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.common.xcontent.ObjectParser;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.index.query.QueryParseContext;
import org.elasticsearch.index.query.QueryShardContext;
import org.elasticsearch.search.DocValueFormat;
import java.io.IOException;
import java.util.Objects;
/**
* A sort builder allowing to sort by score.
*/
public class ScoreSortBuilder extends SortBuilder<ScoreSortBuilder> {
public static final String NAME = "_score";
private static final SortFieldAndFormat SORT_SCORE = new SortFieldAndFormat(
new SortField(null, SortField.Type.SCORE), DocValueFormat.RAW);
private static final SortFieldAndFormat SORT_SCORE_REVERSE = new SortFieldAndFormat(
new SortField(null, SortField.Type.SCORE, true), DocValueFormat.RAW);
/**
* Build a ScoreSortBuilder default to descending sort order.
*/
public ScoreSortBuilder() {
// order defaults to desc when sorting on the _score
order(SortOrder.DESC);
}
/**
* Read from a stream.
*/
public ScoreSortBuilder(StreamInput in) throws IOException {
order(SortOrder.readFromStream(in));
}
@Override
public void writeTo(StreamOutput out) throws IOException {
order.writeTo(out);
}
@Override
public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
builder.startObject();
builder.startObject(NAME);
builder.field(ORDER_FIELD.getPreferredName(), order);
builder.endObject();
builder.endObject();
return builder;
}
/**
* Creates a new {@link ScoreSortBuilder} from the query held by the {@link QueryParseContext} in
* {@link org.elasticsearch.common.xcontent.XContent} format.
*
* @param context the input parse context. The state on the parser contained in this context will be changed as a side effect of this
* method call
* @param fieldName in some sort syntax variations the field name precedes the xContent object that specifies further parameters, e.g.
* in '{ "foo": { "order" : "asc"} }'. When parsing the inner object, the field name can be passed in via this argument
*/
public static ScoreSortBuilder fromXContent(QueryParseContext context, String fieldName) throws IOException {
return PARSER.apply(context.parser(), context);
}
private static ObjectParser<ScoreSortBuilder, QueryParseContext> PARSER = new ObjectParser<>(NAME, ScoreSortBuilder::new);
static {
PARSER.declareString((builder, order) -> builder.order(SortOrder.fromString(order)), ORDER_FIELD);
}
@Override
public SortFieldAndFormat build(QueryShardContext context) {
if (order == SortOrder.DESC) {
return SORT_SCORE;
} else {
return SORT_SCORE_REVERSE;
}
}
@Override
public boolean equals(Object object) {
if (this == object) {
return true;
}
if (object == null || getClass() != object.getClass()) {
return false;
}
ScoreSortBuilder other = (ScoreSortBuilder) object;
return Objects.equals(order, other.order);
}
@Override
public int hashCode() {
return Objects.hash(this.order);
}
@Override
public String getWriteableName() {
return NAME;
}
}