CustomChecker.java

// Start of HEAD
import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
// End of HEAD


// Start of BODY
/**
 * TestStruct::
 *  testcase_id                   [long] ID of the test-case
 *  testcase_input_path           [String] File path to test-case input
 *  testcase_output_path          [String] File path to test-case output generated by the problem solver
 *  testcase_expected_output_path [String] File path to test-case expected output to be matched with
 *  metadata_file_paths           [ArrayList<String>] File paths to Question metadata (Extra files usually used for defining traning sets)
 *  submission_code_path          [String] File path to submission source code
 *  testcase_result               [boolean] Set to true if test-case output matches test-case expected output. Matching is done line by line
 *  testcase_signal               [long] Exit code of the test-case process
 *  testcase_time                 [double] Time taken by the test-case process in seconds
 *  testcase_memory               [long] Peak memory of the test-case process determined in bytes
 *  data                          [String] <Future use>
 *
 *
 *  ResultStruct::
 *    result      [boolean]  Assign test-case result. true determines success. false determines failure
 *    score       [double] Assing test-case score. Normalized between 0 to 1
 *    message     [String] Assing test-case message. This message is visible to the problem solver
**/


public class CustomChecker {

    static void run_custom_checker(final TestStruct t_obj, ResultStruct r_obj) {
        System.out.println("testcase_id: " + t_obj.testcase_id);
        System.out.println("testcase_input_path: " + t_obj.testcase_input_path);
        System.out.println("testcase_output_path: " + t_obj.testcase_output_path);
        System.out.println("testcase_expected_output_path: " + t_obj.testcase_expected_output_path);
        for(String path : t_obj.metadata_file_paths)
            System.out.println("metadata_file_paths: " + path);
        System.out.println("submission_code_path: " + t_obj.submission_code_path);
        System.out.println("testcase_result: " + t_obj.testcase_result);
        System.out.println("testcase_signal: " + t_obj.testcase_signal);
        System.out.println("testcase_time: " + t_obj.testcase_time);
        System.out.println("testcase_memory: " + t_obj.testcase_memory);
        System.out.println("data: " + t_obj.data);

        r_obj.result = true;
        r_obj.score = 1.1d;
        r_obj.message = "Success";
    }
// End of BODY


// Start of TAIL
    static int read_input_json(final String json_file_path, TestStruct t_obj) {
        try {
            JSONParser parser = new JSONParser();
            JSONObject json_obj = (JSONObject)parser.parse(new FileReader(json_file_path));

            // Read values
            t_obj.testcase_id = (long) json_obj.get("testcase_id");
            t_obj.testcase_input_path = (String) json_obj.get("input_file_path");
            t_obj.testcase_output_path = (String) json_obj.get("output_file_path");
            t_obj.testcase_expected_output_path = (String) json_obj.get("expected_output_file_path");

            JSONArray metadata_file_path_node = (JSONArray) json_obj.get("metadata_file_paths");
            if(metadata_file_path_node != null && !metadata_file_path_node.isEmpty()) {
                Iterator<String> metadata_file_paths_it = metadata_file_path_node.iterator();
                while (metadata_file_paths_it.hasNext())
                    t_obj.metadata_file_paths.add(metadata_file_paths_it.next());
            }

            t_obj.submission_code_path = (String) json_obj.get("submission_code_path");
            t_obj.testcase_result = (boolean) json_obj.get("testcase_result");
            t_obj.testcase_signal = (long) json_obj.get("testcase_signal");
            t_obj.testcase_time = ((Number) json_obj.get("testcase_time")).doubleValue();
            t_obj.testcase_memory = (long) json_obj.get("testcase_memory");
            t_obj.data = (String) json_obj.get("data");
        }
        catch(Exception err) {
            return 1;
        }

        return 0;
    }

    static void write_result_json(final ResultStruct r_obj) {
        JSONObject json_obj = new JSONObject();
        json_obj.put("custom_result", new Integer((r_obj.result)? 1 : 0));
        json_obj.put("custom_score", new Double( Math.max(((r_obj.score > 1.0d)? 1.0d : r_obj.score), 0.0d)));
        json_obj.put("custom_message", (r_obj.message.length() > 4096)? r_obj.message.substring(0, 4095) : r_obj.message);
        System.out.println(json_obj);
    }

    public static void main(String args[]) {
        // Input parameters
        TestStruct t_obj = new TestStruct();
        // Out parameters
        ResultStruct r_obj = new ResultStruct();

        if(args.length < 1)
        {
            write_result_json(r_obj);
            System.exit(1);
        }

        // Decode input JSON
        int failure = read_input_json((String)args[0], t_obj);
        // Incase input JSON was malformed or not existent
        if(failure != 0)
        {
            r_obj.message = "Unable to read input json";
            write_result_json(r_obj);
            System.exit(2);
        }

        // Run the custom checker evaluator
        run_custom_checker(t_obj, r_obj);

        // Encode result JSON
        write_result_json(r_obj);
        System.exit(0);
    }
}


final class TestStruct {
    long testcase_id = 0;
    String testcase_input_path;
    String testcase_output_path;
    String testcase_expected_output_path;
    ArrayList<String> metadata_file_paths = new ArrayList<String>();
    String submission_code_path;
    boolean testcase_result = false;
    long testcase_signal = 0;
    double testcase_time = 0.0f;
    long testcase_memory = 0;
    String data;
}


final class ResultStruct {
    boolean result = false;
    double   score = 0.0f;
    String  message = "Uninitialized";
}
// End of TAIL

Testing:
Input file data. Path to be passed as command line argument

{"testcase_id":0,"input_file_path":"/run-XX/input00.txt","output_file_path":"/run-XX/output00.out","expected_output_file_path":"/run-XX/output_expected00.out","metadata_file_paths":["/run-XX/training.txt","/run-XX/training2.txt"],"submission_code_path":"/run-XX/solution.cpp", "testcase_result":true,"testcase_signal":0,"testcase_time":1.2,"testcase_memory":312322,"data":"Data"}

Expected output:

testcase_id: 0
testcase_input_path: /run-XX/input00.txt
testcase_output_path: /run-XX/output00.out
testcase_expected_output_path: /run-XX/output_expected00.out
metadata_file_paths: /run-XX/training.txt
metadata_file_paths: /run-XX/training2.txt
submission_code_path: /run-XX/solution.cpp
testcase_result: true
testcase_signal: 0
testcase_time: 1.2
testcase_memory: 312322
data: Data
{"custom_message":"Success","custom_score":1.0,"custom_result":1}