Azure Cosmos DB Java SDK で ドキュメントがすでにあれば更新、存在しなければ新規作成

package com.microsoft.azure.documentdb.sample;

import java.util.Date;
import java.util.Iterator;

import com.google.gson.Gson;
import com.google.gson.JsonObject;
import com.microsoft.azure.documentdb.ConnectionMode;
import com.microsoft.azure.documentdb.ConnectionPolicy;
import com.microsoft.azure.documentdb.ConsistencyLevel;
import com.microsoft.azure.documentdb.Document;
import com.microsoft.azure.documentdb.DocumentClient;
import com.microsoft.azure.documentdb.FeedOptions;
import com.microsoft.azure.documentdb.FeedResponse;
import com.microsoft.azure.documentdb.ResourceResponse;

public class HelloCosmodDB002UpdateDocument {

    public static void main(String[] args) throws Exception {

        // Azure Cosmos DB Libraries for Java
        // https://docs.microsoft.com/ja-jp/java/api/overview/azure/cosmosdb?view=azure-java-stable

        String host = "{yourhost}";
        String database_id = "{your_database}";
        String collection_id = "{your_collection}";

        // Get key from Azure Web Console
        // read write key
        String key = "{your_key}";

        String endPoint = "https://" + host + ".documents.azure.com:443";

        ConnectionPolicy policy = new ConnectionPolicy();
        policy.setConnectionMode(ConnectionMode.DirectHttps);

        try (DocumentClient client = new DocumentClient(endPoint, key, ConnectionPolicy.GetDefault(),
                ConsistencyLevel.Session)) {

            // Name? ID?
            String collectionLink = String.format("/dbs/%s/colls/%s", database_id, collection_id);

            JsonObject json;

            FeedOptions options = new FeedOptions();
            options.setEnableCrossPartitionQuery(true);

            FeedResponse<Document> res = client.queryDocuments(collectionLink, "SELECT * FROM c WHERE c.id=\"1000\"",
                    options, "{your_pkey}");

            Iterator<Document> itr = res.getQueryIterator();

            if (itr.hasNext()) {
                Document doc = itr.next();
                Gson gson = new Gson();
                json = gson.fromJson(doc.toJson(), JsonObject.class);
            } else {
                json = new JsonObject();
                json.addProperty("id", "1000");
            }

            json.addProperty("text2", "This is test for update.");
            json.addProperty("lastupdate", System.currentTimeMillis());

            Document d = new Document(json.toString());

            ResourceResponse<Document> response = client.upsertDocument(collectionLink, d, null, false);
            client.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}