Feat: Fileparser, file converter, dummydata

Added a file parser class that is responsible for parsing a .txt file that has stocks.

Added a file converter class that is responsible for converting a list of strings (from file parser) to a list of stock objects.

Added dummydata.txt which includes some stocks

src/main/java/edu/ntnu/idi/idatt2003/g40/mappe/FileConverter.java

@@ -0,0 +1,23 @@
+package edu.ntnu.idi.idatt2003.g40.mappe;
+
+import java.io.IOException;
+import java.math.BigDecimal;
+import java.util.ArrayList;
+import java.util.List;
+
+public class FileConverter {
+
+  public List<Stock> getStocksFromFile(FileParser fileParser) throws IOException {
+    List<String> strings = fileParser.readFile();
+    List<Stock> stocksFromFile = new ArrayList<>();
+
+    strings.forEach(s -> {
+      String[] lineElements = s.split(",");
+      String stockSymbol = lineElements[0].trim();
+      String stockName = lineElements[1].trim();
+      BigDecimal stockPrice = new BigDecimal(lineElements[2].trim());
+      stocksFromFile.add(new Stock(stockSymbol, stockName, stockPrice));
+    });
+    return stocksFromFile;
+  }
+}

src/main/java/edu/ntnu/idi/idatt2003/g40/mappe/FileParser.java

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+package edu.ntnu.idi.idatt2003.g40.mappe;
+
+import java.io.IOException;
+import java.math.BigDecimal;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.List;
+import java.util.function.Predicate;
+
+public class FileParser {
+
+  private final String pathName;
+
+  private enum ParserRuleSet {
+    NOT_EMPTY(s -> !s.trim().isEmpty()),
+    NOT_COMMENT(s -> !s.startsWith("#")),
+    VALID_FORMAT(NOT_EMPTY.rule.and(NOT_COMMENT.rule)),
+    VALID_CODE(s -> s.matches("[A-Z]{4}")),
+    VALID_NAME(s -> s.matches(".*")),
+    CAN_PARSE_TO_BIG_DECIMAL(s -> {
+      try {
+        new BigDecimal(s);
+        return true;
+      } catch (NumberFormatException e) {
+        return false;
+      }
+    }),
+    VALID_PRICE_FORMAT(s -> s.matches("[^a-zA-Z]+")),
+    VALID_PRICE(VALID_PRICE_FORMAT.rule.and(CAN_PARSE_TO_BIG_DECIMAL.rule));
+
+    private final Predicate<String> rule;
+
+    ParserRuleSet(final Predicate<String> rule) {
+      this.rule = rule;
+    }
+  }
+
+  public FileParser(final String pathName) {
+    this.pathName = pathName;
+  }
+
+  public List<String> readFile() throws IOException {
+    try {
+      Path path = Paths.get(pathName);
+      List<String> allLines = Files.readAllLines(path);
+      List<String> readableLines = allLines.stream().filter(ParserRuleSet.VALID_FORMAT.rule).toList();
+
+      // Valid lines (following the correct regular expressions)
+      return readableLines.stream().filter(s -> {
+        String[] parts = s.trim().split(",");
+
+        if (parts.length != 3) {
+          return false;
+        }
+
+        boolean validCode = ParserRuleSet.VALID_CODE.rule.test(parts[0].trim());
+        boolean validName = ParserRuleSet.VALID_NAME.rule.test(parts[1].trim());
+        boolean validPrice = ParserRuleSet.VALID_PRICE.rule.test(parts[2].trim());
+
+        return validCode && validName && validPrice;
+      }).toList();
+
+    } catch (IOException e) {
+      throw new IOException("File parser could not parse file!");
+    }
+  }
+}

src/main/resources/dummydata.txt

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+#THIS IS A COMMENT. Below me is an empty line
+
+AAPL, Apple Inc., 276.43
+NVID, Nvidida Corporation, 241.591
+
+#Above me are some valid formats.
+#Below me are some invalid formats
+
+COOLI, This is a cool name, 252.2
+
+COOL, This is a cool name, 252.2a