mongodb.javaGroup.java Source code

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Here is the source code for mongodb.javaGroup.java

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/*
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//Grouping Documents by Field Values in Java.
//to Demostrate generating grouping of documents by field value in Java Applications.

package mongodb;

import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBObject;
import com.mongodb.MongoClient;

/**
 *
 * @author soham
 */
public class javaGroup {
    public static void main(String[] args) {
        try {
            MongoClient mongoClient = new MongoClient("localhost", 27017);
            DB db = mongoClient.getDB("words");
            DBCollection collection = db.getCollection("word_stats");
            javaGroup.firstIsALastIsVowel(collection);
            javaGroup.firstLetterTotals(collection);
        } catch (Exception e) {
            System.out.println(e);
        }
    }

    public static void displayGroup(DBObject result) {
        for (Object name : result.toMap().values()) {
            System.out.println(name);
        }
    }

    public static void firstIsALastIsVowel(DBCollection collection) {
        BasicDBObject key = new BasicDBObject("first", true);
        key.append("last", true);
        BasicDBObject cond = new BasicDBObject("first", "a");
        cond.append("last", new BasicDBObject("$in", new String[] { "a", "e", "i", "o", "u" }));
        BasicDBObject initial = new BasicDBObject("count", 0);
        String reduce = "function (obj, prev) { prev.count++; }";
        DBObject result = collection.group(key, cond, initial, reduce);
        System.out.println("\n'A' words grouped by first and last" + " letter that end with a vowel");
        javaGroup.displayGroup(result);
    }

    public static void firstLetterTotals(DBCollection collection) {
        BasicDBObject key = new BasicDBObject("first", true);
        BasicDBObject cond = new BasicDBObject();
        BasicDBObject initial = new BasicDBObject("vowels", 0);
        initial.append("cons", 0);
        String reduce = "function (obj, prev) { " + "prev.vowels += obj.stats.vowels; "
                + "prev.cons += obj.stats.consonants; " + "}";
        String finalize = "function (obj) { " + "obj.total = obj.vowels + obj.cons; " + "}";
        DBObject result = collection.group(key, cond, initial, reduce, finalize);
        System.out.println("\nWords grouped by first letter " + "with totals: ");
        javaGroup.displayGroup(result);
    }
}