Add Parser class

src/main/java/org/RI/P2/Parser.java

@@ -0,0 +1,32 @@
+package org.RI.P2;
+
+import java.util.List;
+import java.io.IOException;
+import java.io.File;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.stream.Collectors;
+
+public class Parser {
+    private static List<File> files;
+
+    private static void readFiles(String directory) throws IOException {
+        files = Files.walk(Paths.get(directory)).filter(Files::isRegularFile).map(Path::toFile)
+                .collect(Collectors.toList());
+    }
+
+    private static void usage() {
+        System.out.println("Usage: Parser <directory>");
+        System.out.println("option directory: directory that contains JSON files");
+        System.exit(1);
+    }
+
+    public static void main(String[] args) throws IOException {
+        if (args.length != 1) {
+            usage();
+        }
+        String directory = args[0];
+        readFiles(directory);
+    }
+}