package seedu.address.logic.parser;

import static seedu.address.commons.core.Messages.MESSAGE_INVALID_COMMAND_FORMAT;
import static seedu.address.logic.parser.CliSyntax.PREFIX_END_TIME;
import static seedu.address.logic.parser.CliSyntax.PREFIX_PRIORITY;
import static seedu.address.logic.parser.CliSyntax.PREFIX_START_TIME;
import static seedu.address.logic.parser.CliSyntax.PREFIX_TAG;
import static seedu.address.logic.parser.CliSyntax.PREFIX_TIME;

import java.util.NoSuchElementException;

import seedu.address.commons.exceptions.IllegalValueException;
import seedu.address.logic.commands.AddCommand;
import seedu.address.logic.commands.Command;
import seedu.address.logic.commands.IncorrectCommand;

/**
 * Parses input arguments and creates a new AddCommand object
 */
public class AddCommandParser {

    /**
     * Parses the given {@code String} of arguments in the context of the AddCommand
     * and returns an AddCommand object for execution.
     */
    public Command parse(String args) {
        ArgumentTokenizer argsTokenizer =
                new ArgumentTokenizer(PREFIX_TIME, PREFIX_START_TIME, PREFIX_END_TIME, PREFIX_PRIORITY, PREFIX_TAG);
        argsTokenizer.tokenize(args);
        String priority;
        
        //@@author A0143873Y
        //Making priority to be optionally null.
        try {
            priority = argsTokenizer.getValue(PREFIX_PRIORITY).get();
        } catch (NoSuchElementException nsee) {
            priority = null;
        } 
        
        try {
            return new AddCommand(
                    argsTokenizer.getPreamble().get(),
                    argsTokenizer.getValue(PREFIX_START_TIME).get(),
                    argsTokenizer.getValue(PREFIX_END_TIME).get(),
                    priority,
                    ParserUtil.toSet(argsTokenizer.getAllValues(PREFIX_TAG))
            );
        } catch (NoSuchElementException nsee) {
            return new IncorrectCommand(String.format(MESSAGE_INVALID_COMMAND_FORMAT, AddCommand.MESSAGE_USAGE));
        } catch (IllegalValueException ive) {
            return new IncorrectCommand(ive.getMessage());
        }
        //@@author
    }

}

package seedu.address.logic.parser;

import static seedu.address.commons.core.Messages.MESSAGE_INVALID_COMMAND_FORMAT;
import static seedu.address.logic.parser.CliSyntax.PREFIX_END_TIME;
import static seedu.address.logic.parser.CliSyntax.PREFIX_PRIORITY;
import static seedu.address.logic.parser.CliSyntax.PREFIX_START_TIME;
import static seedu.address.logic.parser.CliSyntax.PREFIX_TAG;
import static seedu.address.logic.parser.CliSyntax.PREFIX_TIME;

import java.util.NoSuchElementException;

import seedu.address.commons.exceptions.IllegalValueException;
import seedu.address.logic.commands.AddCommand;
import seedu.address.logic.commands.Command;
import seedu.address.logic.commands.IncorrectCommand;

/**
 * Parses input arguments and creates a new AddCommand object
 */
public class AddCommandParser {

    /**
     * Parses the given {@code String} of arguments in the context of the AddCommand
     * and returns an AddCommand object for execution.
     */
    public Command parse(String args) {
        ArgumentTokenizer argsTokenizer =
                new ArgumentTokenizer(PREFIX_TIME, PREFIX_START_TIME, PREFIX_END_TIME, PREFIX_PRIORITY, PREFIX_TAG);
        argsTokenizer.tokenize(args);
        String priority;

        //@@author A0143873Y
        //Making priority to be optionally null.
        try {
            priority = argsTokenizer.getValue(PREFIX_PRIORITY).get();
        } catch (NoSuchElementException nsee) {
            priority = null;
        }

        try {
            return new AddCommand(
                    argsTokenizer.getPreamble().get(),
                    argsTokenizer.getValue(PREFIX_START_TIME).get(),
                    argsTokenizer.getValue(PREFIX_END_TIME).get(),
                    priority,
                    ParserUtil.toSet(argsTokenizer.getAllValues(PREFIX_TAG))
            );
        } catch (NoSuchElementException nsee) {
            return new IncorrectCommand(String.format(MESSAGE_INVALID_COMMAND_FORMAT, AddCommand.MESSAGE_USAGE));
        } catch (IllegalValueException ive) {
            return new IncorrectCommand(ive.getMessage());
        }
        //@@author
    }

}

Fix whitespaces