import org.elasticsearch.search.aggregations.bucket.SingleBucketAggregation; //导入依赖的package包/类
private  void handleAggregations(Aggregations aggregations, List<String> headers, List<List<String>> lines) throws CsvExtractorException {
    if(allNumericAggregations(aggregations)){
        lines.get(this.currentLineIndex).addAll(fillHeaderAndCreateLineForNumericAggregations(aggregations, headers));
        return;
    }
    //aggregations with size one only supported when not metrics.
    List<Aggregation> aggregationList = aggregations.asList();
    if(aggregationList.size() > 1){
        throw new CsvExtractorException("currently support only one aggregation at same level (Except for numeric metrics)");
    }
    Aggregation aggregation = aggregationList.get(0);
    //we want to skip singleBucketAggregations (nested,reverse_nested,filters)
    if(aggregation instanceof SingleBucketAggregation){
        Aggregations singleBucketAggs = ((SingleBucketAggregation) aggregation).getAggregations();
        handleAggregations(singleBucketAggs, headers, lines);
        return;
    }
    if(aggregation instanceof NumericMetricsAggregation){
        handleNumericMetricAggregation(headers, lines.get(currentLineIndex), aggregation);
        return;
    }
    if(aggregation instanceof GeoBounds){
        handleGeoBoundsAggregation(headers, lines, (GeoBounds) aggregation);
        return;
    }
    if(aggregation instanceof TopHits){
        //todo: handle this . it returns hits... maby back to normal?
        //todo: read about this usages
        // TopHits topHitsAggregation = (TopHits) aggregation;
    }
    if(aggregation instanceof MultiBucketsAggregation){
        MultiBucketsAggregation bucketsAggregation = (MultiBucketsAggregation) aggregation;
        String name = bucketsAggregation.getName();
        //checking because it can comes from sub aggregation again
        if(!headers.contains(name)){
            headers.add(name);
        }
        Collection<? extends MultiBucketsAggregation.Bucket> buckets = bucketsAggregation.getBuckets();

        //clone current line.
        List<String> currentLine = lines.get(this.currentLineIndex);
        List<String> clonedLine = new ArrayList<>(currentLine);

        //call handle_Agg with current_line++
        boolean firstLine = true;
        for (MultiBucketsAggregation.Bucket bucket : buckets) {
            //each bucket need to add new line with current line copied => except for first line
            String key = bucket.getKeyAsString();
            if(firstLine){
                firstLine = false;
            }
            else {
                currentLineIndex++;
                currentLine = new ArrayList<String>(clonedLine);
                lines.add(currentLine);
            }
            currentLine.add(key);
            handleAggregations(bucket.getAggregations(),headers,lines);

        }
    }

}
 

import org.elasticsearch.search.aggregations.bucket.SingleBucketAggregation; //导入依赖的package包/类
private  Aggregation skipAggregations(Aggregation firstAggregation) {
    while(firstAggregation instanceof SingleBucketAggregation){
        firstAggregation = getFirstAggregation(((SingleBucketAggregation) firstAggregation).getAggregations());
    }
    return firstAggregation;
}
 

import org.elasticsearch.search.aggregations.bucket.SingleBucketAggregation; //导入依赖的package包/类
private void handleAggregations(Aggregations aggregations, List<String> headers, List<List<Object>> lines) throws ObjectResultsExtractException {
    if (allNumericAggregations(aggregations)) {
        lines.get(this.currentLineIndex).addAll(fillHeaderAndCreateLineForNumericAggregations(aggregations, headers));
        return;
    }
    //aggregations with size one only supported when not metrics.
    List<Aggregation> aggregationList = aggregations.asList();
    if (aggregationList.size() > 1) {
        throw new ObjectResultsExtractException("currently support only one aggregation at same level (Except for numeric metrics)");
    }
    Aggregation aggregation = aggregationList.get(0);
    //we want to skip singleBucketAggregations (nested,reverse_nested,filters)
    if (aggregation instanceof SingleBucketAggregation) {
        Aggregations singleBucketAggs = ((SingleBucketAggregation) aggregation).getAggregations();
        handleAggregations(singleBucketAggs, headers, lines);
        return;
    }
    if (aggregation instanceof NumericMetricsAggregation) {
        handleNumericMetricAggregation(headers, lines.get(currentLineIndex), aggregation);
        return;
    }
    if (aggregation instanceof GeoBounds) {
        handleGeoBoundsAggregation(headers, lines, (GeoBounds) aggregation);
        return;
    }
    if (aggregation instanceof TopHits) {
        //todo: handle this . it returns hits... maby back to normal?
        //todo: read about this usages
        // TopHits topHitsAggregation = (TopHits) aggregation;
    }
    if (aggregation instanceof MultiBucketsAggregation) {
        MultiBucketsAggregation bucketsAggregation = (MultiBucketsAggregation) aggregation;
        String name = bucketsAggregation.getName();
        //checking because it can comes from sub aggregation again
        if (!headers.contains(name)) {
            headers.add(name);
        }
        Collection<? extends MultiBucketsAggregation.Bucket> buckets = bucketsAggregation.getBuckets();

        //clone current line.
        List<Object> currentLine = lines.get(this.currentLineIndex);
        List<Object> clonedLine = new ArrayList<>(currentLine);

        //call handle_Agg with current_line++
        boolean firstLine = true;
        for (MultiBucketsAggregation.Bucket bucket : buckets) {
            //each bucket need to add new line with current line copied => except for first line
            String key = bucket.getKeyAsString();
            if (firstLine) {
                firstLine = false;
            } else {
                currentLineIndex++;
                currentLine = new ArrayList<Object>(clonedLine);
                lines.add(currentLine);
            }
            currentLine.add(key);
            handleAggregations(bucket.getAggregations(), headers, lines);

        }
    }

}
 

import org.elasticsearch.search.aggregations.bucket.SingleBucketAggregation; //导入依赖的package包/类
private Aggregation skipAggregations(Aggregation firstAggregation) {
    while (firstAggregation instanceof SingleBucketAggregation) {
        firstAggregation = getFirstAggregation(((SingleBucketAggregation) firstAggregation).getAggregations());
    }
    return firstAggregation;
}
 

import org.elasticsearch.search.aggregations.bucket.SingleBucketAggregation; //导入依赖的package包/类
protected Iterable<SingleBucketAggregation> toSingleBucket(Aggregations aggregations) {
    return from(aggregations)
            .transform(input -> (SingleBucketAggregation) input);
}