week2.MongoDBSparkFreemarkerStyle.java Source code

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Here is the source code for week2.MongoDBSparkFreemarkerStyle.java

Source

package week2;
/*
 * Copyright 2015 MongoDB, Inc.
 *
 * Licensed 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.
 */

import com.mongodb.MongoClient;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;
import freemarker.template.Configuration;
import freemarker.template.Template;
import org.bson.Document;

import java.io.StringWriter;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import static java.util.Arrays.asList;
import static spark.Spark.get;
import static spark.Spark.halt;

public class MongoDBSparkFreemarkerStyle {
    public static void main(String[] args) {
        final Configuration configuration = new Configuration();
        configuration.setClassForTemplateLoading(MongoDBSparkFreemarkerStyle.class, "/week2/freemarker");

        MongoClient client = new MongoClient();
        MongoDatabase database = client.getDatabase("m101");
        final MongoCollection<Document> collection = database.getCollection("funnynumbers");

        get("/", (request, response) -> {
            StringWriter writer = new StringWriter();
            try {
                Template template = configuration.getTemplate("answer.ftl");

                // Not necessary yet to understand this.  It's just to prove that you
                // are able to run a command on a mongod server
                List<Document> results = collection.aggregate(asList(
                        new Document("$group",
                                new Document("_id", "$value").append("count", new Document("$sum", 1))),
                        new Document("$match", new Document("count", new Document("$lte", 2))),
                        new Document("$sort", new Document("_id", 1)))).into(new ArrayList<>());

                int answer = 0;
                for (Document cur : results) {
                    answer += (Double) cur.get("_id");
                }

                Map<String, String> answerMap = new HashMap<>();
                answerMap.put("answer", Integer.toString(answer));

                template.process(answerMap, writer);
            } catch (Exception e) {
                e.printStackTrace();
                halt(500);
            }
            return writer;
        });
    }
}