Seed code - Boilerplate for step 5 - Database Engine Assignment

Problem Statement

Until step 4, we are not fetching data from the file.

In this step, we will begin executing the queries - we will read the data from the CSV file based on to the query and filter the fields and records based on "select" and "where" condition. We will store the extracted data in a separate JSON file named result.json.

Please note that in this step, we are not handling aggregate functions, group by and order by.

For Example

1. Filter the data based on selected fields.

        Query : select city,winner,team1,team2 from data/ipl.csv;
        Expected Output in JSON file:
   
                   {
                      "1": {
                        "winner": "Kolkata Knight Riders",
                        "city": "Bangalore",
                        "team1": "Kolkata Knight Riders",
                        "team2": "Royal Challengers Bangalore"
                      },
                      "2": {
                        "winner": "Chennai Super Kings",
                        "city": "Chandigarh",
                        "team1": "Chennai Super Kings",
                        "team2": "Kings XI Punjab"
                      },
                      "3": {
                        "winner": "Delhi Daredevils",
                        "city": "Delhi",
                        "team1": "Rajasthan Royals",
                        "team2": "Delhi Daredevils"
                      },
                      "4": {
                        "winner": "Royal Challengers Bangalore",
                        "city": "Mumbai",
                        "team1": "Mumbai Indians",
                        "team2": "Royal Challengers Bangalore"
                      },
                      "5": {
                        "winner": "Kolkata Knight Riders",
                        "city": "Kolkata",
                        "team1": "Deccan Chargers",
                        "team2": "Kolkata Knight Riders"
                      }, ......
                         ......
                    }
   

2. Filter the data based on the query with multiple where conditions.

        Query : select city, win_by_runs, season from data/ipl.csv where season > 2014 and city ='Bangalore'
        Expected output in JSON File:
                {
                  "1": {
                    "city": "Bangalore",
                    "season": "2015",
                    "win_by_runs": "0"
                  },
                  "2": {
                    "city": "Bangalore",
                    "season": "2015",
                    "win_by_runs": "18"
                  },
                  "3": {
                    "city": "Bangalore",
                    "season": "2015",
                    "win_by_runs": "27"
                  },
                  "4": {
                    "city": "Bangalore",
                    "season": "2015",
                    "win_by_runs": "0"
                  },
                  "5": {
                    "city": "Bangalore",
                    "season": "2015",
                    "win_by_runs": "0"
                  }, .....
                     .....
                }
   

Note : Once you have cloned boilerplate from the given gitlab URL, import the project into eclipse. Your project’s test cases might show compile time errors for methods, as you have not written the complete code.

Expected solution

A JSON file containing the filtered result set.

Following are the broad tasks:

• Read the query from the user
• parse the query
• forward the object of query parameter to CsvQueryProcessor
• filter out rows basis on the conditions mentioned in the where clause
• write the result set into a JSON file

Project structure

The folders and files you see in this repositories, is how it is expected to be in projects, which are submitted for automated evaluation by Hobbes

Project
|
├── data 			                    // If project needs any data file, it can be found here/placed here, if data is huge they can be mounted, no need put it in your repository
|
├── com.stackroute.datamunger	            // all your java file will be stored in this package
|	    └── DataMunger.java	                        // This is the main file, all your logic is written in this file only   
├── com.stackroute.datamunger.query
|		└── DataSet.java 		                    // This class will be acting as the DataSet containing multiple rows
|		└── DataTypeDefinitions.java                // This class contains methods to find the column data types
|		└── Filter.java 		                    // This class contains methods to evaluate expressions
|		└── Header.java                             // This class implements the getHeader method to return a Header object which contains a String array for containing headers.
|		└── Query.java                              // This class selects the appropriate processor based on the type of query
|		└── Row.java                                // This class contains the row object as ColumnName/Value 
|		└── RowDataTypeDefinitions.java             // This class will be used to store the column data types as columnIndex/DataType
├── com.stackroute.datamunger.query.parser
|		└── AggregateFunction.java                  // This class is used to store Aggregate Function
|		└── QueryParameter.java                     // This class contains the parameters and accessor/mutator methods of QueryParameter
|		└── QueryParser.java                        // This class will parse the queryString and return an object of QueryParameter class
|		└── Restriction.java	                    // This class is for storing Restriction object
├── com.stackroute.datamunger.reader
|		└── CsvQueryProcessor.java                  // This class is used to read data from CSV file
|		└── QueryProcessingEngine.java              // This is an interface with getResultset() in it.
├── com.stackroute.datamunger.test
|	    └── DataMungerTest.java                     // all your test cases are written using JUnit, these test cases can be run by selecting Run As -> JUnit Test 
├── com.stackroute.datamunger.writer
|		└── JsonWriter.java                         // This class writes the result in a JSON file
|
├── .classpath			                            // This file is generated automatically while creating the project in eclipse
├── .hobbes   			                    // Hobbes specific config options, such as type of evaluation schema, type of tech stack etc., Have saved a default values for convenience
├── .project			                    // This is automatically generated by eclipse, if this file is removed your eclipse will not recognize this as your eclipse project. 
├── pom.xml 			                    // This is a default file generated by maven, if this file is removed your project will not get recognized in hobbes.
└── PROBLEM.md  		                    // This files describes the problem of the assignment/project, you can provide as much as information and clarification you want about the project in this file

PS: All lint rule files are by default copied during the evaluation process, however if need to be customizing, you should copy from this repo and modify in your project repo

To use this as a boilerplate for your new project, you can follow these steps

1. Clone the base boilerplate in the folder assignment-solution-step5 of your local machine

   git clone https://gitlab.stackroute.in/Boeing-Immersive/wave1/DataMungerStep5_Boilerplate.git assignment-solution-step5

2. Navigate to assignment-solution-step5 folder

   cd assignment-solution-step5

3. Remove its remote or original reference

   git remote rm origin

4. Create a new repo in gitlab named assignment-solution-step5 as private repo

5. Add your new repository reference as remote

   git remote add origin https://gitlab.stackroute.in/{{yourusername}}/assignment-solution-step5.git

   Note: {{yourusername}} should be replaced by your username from gitlab

6. Check the status of your repo

   git status

7. Use the following command to update the index using the current content found in the working tree, to prepare the content staged for the next commit.

   git add .

8. Commit and Push the project to git

   git commit -a -m "Initial commit | or place your comments according to your need"

   git push -u origin master

9. Check on the git repo online, if the files have been pushed

Important instructions for Participants

• We expect you to write the assignment on your own by following through the guidelines, learning plan, and the practice exercises
• The code must not be plagiarized, the mentors will randomly pick the submissions and may ask you to explain the solution
• The code must be properly indented, code structure maintained as per the boilerplate and properly commented
• Follow through the problem statement shared with you

Further Instructions on Release

*** Release 0.1.0 ***

• Right click on the Assignment select Run As -> Java Application to run your Assignment.
• Right click on the Assignment select Run As -> JUnit Test to run your Assignment.