Pratyush Ghosh - Project Portfolio

The user enters the command find drug [drugname], which is parsed by FindCommandParser to ensure that it has a single argument only - [drugname] - and that the argument contains only uppercase and lowercase alphabets.

If errors are found in the input, a ParseException is thrown and the user sees an error message containing the proper command syntax. If the input is valid, a FindCommand is generated with a trimmed, lowercase version of [drugname] as its search string, and DRUG as its command type.

FindCommand is executed through its execute() method, and calls the static DrugSearch.find() method with the search string as an argument.

The DrugSearch.find() method ensures that the search string does not match any of a list of generic words like "syrup" or "tablet" which are not suitable search phrases, as they would generate hundreds of results. If the check fails, a specific error string is returned, whereupon the FindCommand object throws a command exception, notifying the user that their search string is too generic.

If the check passes, the DrugSearch.find() method creates a DrugCsvUtil object as a local variable, passing in the search string as an input to its constructor. The DrugCsvUtil object now corresponds to that search string only.

The DrugCsvUtil contains a nextMatchingResult method which reads a static drug database stored in "datasetForDrugs.csv" (formatted in UTF-8) from top to bottom, and each time it is called, it returns the next matching result from the database in the form of a String[]. Once there are no matching results, it begins to return null.

The DrugSearch.find() method adds the matching results returned by the DrugCsvUtil to a static cache, one after the other. Once it receives null as a return value, it formats just the Name, Classification and Active Ingredient(s) of the drug results in the cache into a String of search results and returns it to FindCommand, which displays them. The full information can be displayed using the moreinfo command (discussed later). If the cache is empty (i.e. there were no matches in the database), DrugSearch.find() returns a specific error String instead, whereupon FindCommand throws a CommandException, and the user sees an error message indicating that no results were found.

The cache is not cleared at the end of the search: instead, it is cleared when a _new_search is initiated, in order to accommodate the moreinfo command.

When the results are displayed to the user in the form of a numbered list, they have the option of entering the command moreinfo [RESULTNO] to view more information about any of the results.

The argument of the command is parsed by MoreInfoCommandParser to ensure that it is numeric, not less than or equal to zero, and is less than 10,000. If the parse fails, a ParseException is thrown and the user sees the error message that corresponds to the problem with their input.

If the parse is successful, a MoreInfoCommand object is created, which executes through its execute() method, and calls DrugSearch.moreInfo() with the index number as its argument.

DrugSearch.moreInfo() checks that the index is in the cache of results from the most recent search. If the cache is empty, this means that the user has not carried out a single drug search yet, or that the most recent drug search turned up no results. In these cases, a specific error string is returned, and MoreInfoCommand throws a CommandException, and the user sees the appropriate error message.

If the index is contained in the cache, the full information about the corresponding drug (seven categories of information) is formatted into a String result and returned, which is then displayed.