RestFieldStatsAction.java example

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 * 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,
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package org.elasticsearch.rest.action;

import org.elasticsearch.action.fieldstats.FieldStats;
import org.elasticsearch.action.fieldstats.FieldStatsRequest;
import org.elasticsearch.action.fieldstats.FieldStatsResponse;
import org.elasticsearch.action.support.IndicesOptions;
import org.elasticsearch.client.node.NodeClient;
import org.elasticsearch.common.Strings;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.common.xcontent.XContentParser;
import org.elasticsearch.rest.BaseRestHandler;
import org.elasticsearch.rest.BytesRestResponse;
import org.elasticsearch.rest.RestController;
import org.elasticsearch.rest.RestRequest;
import org.elasticsearch.rest.RestResponse;
import org.elasticsearch.rest.RestStatus;

import java.io.IOException;
import java.util.Map;

import static org.elasticsearch.rest.RestRequest.Method.GET;
import static org.elasticsearch.rest.RestRequest.Method.POST;
import static org.elasticsearch.rest.action.RestActions.buildBroadcastShardsHeader;

public class RestFieldStatsAction extends BaseRestHandler {
    public RestFieldStatsAction(Settings settings, RestController controller) {
        super(settings);
        controller.registerAsDeprecatedHandler(GET, "/_field_stats", this,
             deprecationMessage(), deprecationLogger);
        controller.registerAsDeprecatedHandler(POST, "/_field_stats", this,
            deprecationMessage(), deprecationLogger);
        controller.registerAsDeprecatedHandler(GET, "/{index}/_field_stats", this,
            deprecationMessage(), deprecationLogger);
        controller.registerAsDeprecatedHandler(POST, "/{index}/_field_stats", this,
            deprecationMessage(), deprecationLogger);
    }

    static String deprecationMessage() {
        return "[_field_stats] endpoint is deprecated! Use [_field_caps] instead or " +
            "run a min/max aggregations on the desired fields.";
    }

    @Override
    public RestChannelConsumer prepareRequest(final RestRequest request,
                                              final NodeClient client) throws IOException {
        if (request.hasContentOrSourceParam() && request.hasParam("fields")) {
            throw new IllegalArgumentException("can't specify a request body and [fields] request parameter, " +
                "either specify a request body or the [fields] request parameter");
        }

        final FieldStatsRequest fieldStatsRequest = new FieldStatsRequest();
        fieldStatsRequest.indices(Strings.splitStringByCommaToArray(request.param("index")));
        fieldStatsRequest.indicesOptions(IndicesOptions.fromRequest(request, fieldStatsRequest.indicesOptions()));
        fieldStatsRequest.level(request.param("level", FieldStatsRequest.DEFAULT_LEVEL));
        if (request.hasContentOrSourceParam()) {
            try (XContentParser parser = request.contentOrSourceParamParser()) {
                fieldStatsRequest.source(parser);
            }
        } else {
            fieldStatsRequest.setFields(Strings.splitStringByCommaToArray(request.param("fields")));
        }

        return channel -> client.fieldStats(fieldStatsRequest, new RestBuilderListener<FieldStatsResponse>(channel) {
            @Override
            public RestResponse buildResponse(FieldStatsResponse response, XContentBuilder builder) throws Exception {
                builder.startObject();
                buildBroadcastShardsHeader(builder, request, response);

                builder.startObject("indices");
                for (Map.Entry<String, Map<String, FieldStats>> entry1 :
                        response.getIndicesMergedFieldStats().entrySet()) {
                    builder.startObject(entry1.getKey());
                    builder.startObject("fields");
                    for (Map.Entry<String, FieldStats> entry2 : entry1.getValue().entrySet()) {
                        builder.field(entry2.getKey());
                        entry2.getValue().toXContent(builder, request);
                    }
                    builder.endObject();
                    builder.endObject();
                }
                builder.endObject();
                if (response.getConflicts().size() > 0) {
                    builder.startObject("conflicts");
                    for (Map.Entry<String, String> entry : response.getConflicts().entrySet()) {
                        builder.field(entry.getKey(), entry.getValue());
                    }
                    builder.endObject();
                }
                builder.endObject();
                return new BytesRestResponse(RestStatus.OK, builder);
            }
        });
    }
}