FunctionFactory.java

package com.silverforge.elasticsearchrawclient.queryDSL.generator;

import com.silverforge.elasticsearchrawclient.model.QueryTypeItem;
import com.silverforge.elasticsearchrawclient.utils.QueryTypeArrayList;

import java.util.Map;

import static br.com.zbra.androidlinq.Linq.stream;

public final class FunctionFactory {

    public static DecayFunctionGenerator gaussGenerator() {
        return new DecayFunctionGenerator("gauss");
    }

    public static DecayFunctionGenerator expGenerator() {
        return new DecayFunctionGenerator("exp");
    }

    public static DecayFunctionGenerator linearGenerator() {
        return new DecayFunctionGenerator("linear");
    }

    public static WeightGenerator weightGenerator() {
        return new WeightGenerator();
    }

    public static ScriptScoreGenerator scriptScoreGenerator() {
        return new ScriptScoreGenerator();
    }

    public static RandomScoreGenerator randomScoreGenerator() {
        return new RandomScoreGenerator();
    }

    public static FieldValueFactorGenerator fieldValueFactorGenerator() {
        return new FieldValueFactorGenerator();
    }

    public static class WeightGenerator
            extends QueryGenerator {

        private WeightGenerator() {}

        @Override
        public String generate(QueryTypeArrayList<QueryTypeItem> queryBag) {
            Map<String, String> childItems = stream(queryBag)
                .toMap(q -> q.getName(), q -> q.getValue());

            return generateFunctionChildren(childItems);
        }
    }

    public static class ScriptScoreGenerator
            extends QueryGenerator {

        private ScriptScoreGenerator() {}

        @Override
        public String generate(QueryTypeArrayList<QueryTypeItem> queryBag) {
            Map<String, String> childItems = stream(queryBag)
                .toMap(q -> q.getName(), q -> q.getValue());

            return generateScriptScoreChildren("script_score", childItems);
        }
    }

    public static class RandomScoreGenerator
            extends QueryGenerator {

        private RandomScoreGenerator() {}

        @Override
        public String generate(QueryTypeArrayList<QueryTypeItem> queryBag) {
            Map<String, String> childItems = stream(queryBag)
                .toMap(q -> q.getName(), q -> q.getValue());

            return generateFunctionChildren("random_score", childItems);
        }
    }

    public static class FieldValueFactorGenerator
            extends QueryGenerator {

        private FieldValueFactorGenerator() {}

        @Override
        public String generate(QueryTypeArrayList<QueryTypeItem> queryBag) {
            Map<String, String> childItems = stream(queryBag)
                .toMap(q -> q.getName(), q -> q.getValue());

            return generateFunctionChildren("field_value_factor", childItems);
        }
    }

    public static class DecayFunctionGenerator
            extends QueryGenerator {

        private String functionName;

        private DecayFunctionGenerator(String functionName) {
            this.functionName = functionName;
        }

        @Override
        public String generate(QueryTypeArrayList<QueryTypeItem> queryBag) {

            QueryTypeItem parent = stream(queryBag)
                .firstOrNull(q -> q.isParent());

            Map<String, String> childItems = stream(queryBag)
                .where(q -> !q.isParent())
                .toMap(q -> q.getName(), q -> q.getValue());

            return generateDecayFunction(functionName, parent, childItems);
        }
    }
}