/*
* 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.index.query.functionscore;
import org.elasticsearch.common.io.stream.NamedWriteable;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.common.lucene.search.function.ScoreFunction;
import org.elasticsearch.common.lucene.search.function.WeightFactorFunction;
import org.elasticsearch.common.xcontent.ToXContent;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.index.query.QueryShardContext;
import java.io.IOException;
import java.util.Objects;
public abstract class ScoreFunctionBuilder<FB extends ScoreFunctionBuilder<FB>> implements ToXContent, NamedWriteable {
private Float weight;
/**
* Standard empty constructor.
*/
public ScoreFunctionBuilder() {
}
/**
* Read from a stream.
*/
public ScoreFunctionBuilder(StreamInput in) throws IOException {
weight = in.readOptionalFloat();
}
@Override
public final void writeTo(StreamOutput out) throws IOException {
out.writeOptionalFloat(weight);
doWriteTo(out);
}
/**
* Write the subclass's components into the stream.
*/
protected abstract void doWriteTo(StreamOutput out) throws IOException;
/**
* The name of this score function.
*/
public abstract String getName();
/**
* Set the weight applied to the function before combining.
*/
@SuppressWarnings("unchecked")
public final FB setWeight(float weight) {
this.weight = weight;
return (FB) this;
}
/**
* The weight applied to the function before combining.
*/
public final Float getWeight() {
return weight;
}
@Override
public final XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
if (weight != null) {
builder.field(FunctionScoreQueryBuilder.WEIGHT_FIELD.getPreferredName(), weight);
}
doXContent(builder, params);
return builder;
}
/**
* Convert this subclass's data into XContent.
*/
protected abstract void doXContent(XContentBuilder builder, Params params) throws IOException;
@Override
public final String getWriteableName() {
return getName();
}
@Override
public final boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null || getClass() != obj.getClass()) {
return false;
}
@SuppressWarnings("unchecked")
FB other = (FB) obj;
return Objects.equals(weight, other.getWeight()) &&
doEquals(other);
}
/**
* Check that two instances of the same subclass of ScoreFunctionBuilder are equal. Implementers don't need to check any fields in
* ScoreFunctionBuilder, just fields that they define.
*/
protected abstract boolean doEquals(FB functionBuilder);
@Override
public final int hashCode() {
return Objects.hash(getClass(), weight, doHashCode());
}
/**
* Hashcode for fields defined in this subclass of ScoreFunctionBuilder. Implementers should ignore fields defined in
* ScoreFunctionBuilder because they will already be in the hashCode.
*/
protected abstract int doHashCode();
/**
* Called on a data node, converts this ScoreFunctionBuilder into its corresponding Lucene function object.
*/
public final ScoreFunction toFunction(QueryShardContext context) throws IOException {
ScoreFunction scoreFunction = doToFunction(context);
if (weight == null) {
return scoreFunction;
}
return new WeightFactorFunction(weight, scoreFunction);
}
/**
* Build the Lucene ScoreFunction for this builder. Implementers should ignore things defined in ScoreFunctionBuilder like weight as
* they will be handled by the function that calls this one.
*/
protected abstract ScoreFunction doToFunction(QueryShardContext context) throws IOException;
}