diff --git a/src/IO/Exception/DirectoryNotReadableException.php b/src/IO/Exception/DirectoryNotReadableException.php
new file mode 100644
index 0000000..ce647a7
--- /dev/null
+++ b/src/IO/Exception/DirectoryNotReadableException.php
@@ -0,0 +1,11 @@
+<?php
+
+namespace IO\Exception;
+
+class DirectoryNotReadableException extends IOException
+{
+    public function __construct(string $directory)
+    {
+        parent::__construct(sprintf('Directory \'%s\' is not readable', $directory));
+    }
+}
diff --git a/src/IO/Input/FinderArguments.php b/src/IO/Input/FinderArguments.php
index aa56bfd..f1c568c 100644
--- a/src/IO/Input/FinderArguments.php
+++ b/src/IO/Input/FinderArguments.php
@@ -5,6 +5,7 @@ namespace IO\Input;
 use Filter\DocumentFilter;
 use Filter\FilterFactory;
 use IO\Exception\DirectoryNotFoundException;
+use IO\Exception\DirectoryNotReadableException;
 use IO\Exception\NotADirectoryException;
 
 class FinderArguments
@@ -14,15 +15,6 @@ class FinderArguments
     private ?string $directory;
     private array $filters;
 
-    public function __construct(?string $directory, array $filters)
-    {
-        $this->directory = $directory;
-        $this->filters = $filters;
-
-        $factory = new FilterFactory();
-        $this->filters = array_map([$factory, 'createFromString'], $this->filters);
-    }
-
     public static function createFromGlobals(): self
     {
         $arguments = self::getArguments();
@@ -33,15 +25,17 @@ class FinderArguments
         return new self($dir, $arguments);
     }
 
+    public function __construct(?string $directory, array $filters)
+    {
+        $this->guardUnusableDirectory($directory);
+        $this->directory = realpath($directory);
+
+        $factory = new FilterFactory();
+        $this->filters = array_map([$factory, 'createFromString'], $filters);
+    }
+
     public function getDirectory(): string
     {
-        if (!file_exists($this->directory)) {
-            throw new DirectoryNotFoundException($this->directory);
-        }
-        if (!is_dir($this->directory)) {
-            throw new NotADirectoryException($this->directory);
-        }
-        
         return $this->directory;
     }
 
@@ -52,4 +46,17 @@ class FinderArguments
     {
         return $this->filters;
     }
+
+    private function guardUnusableDirectory(string $directory): void
+    {
+        if (!file_exists($directory)) {
+            throw new DirectoryNotFoundException($directory);
+        }
+        if (!is_dir($directory)) {
+            throw new NotADirectoryException($directory);
+        }
+        if (!is_readable($directory)) {
+            throw new DirectoryNotReadableException($directory);
+        }
+    }
 }
diff --git a/src/IO/Input/ShowInfoArguments.php b/src/IO/Input/ShowInfoArguments.php
index 5659094..f591d34 100644
--- a/src/IO/Input/ShowInfoArguments.php
+++ b/src/IO/Input/ShowInfoArguments.php
@@ -11,12 +11,7 @@ class ShowInfoArguments
 {
     use ArgvAccess;
 
-    private ?string $file;
-
-    public function __construct(?string $file)
-    {
-        $this->file = $file;
-    }
+    private SplFileInfo $file;
 
     public static function createFromGlobals(): self
     {
@@ -24,18 +19,27 @@ class ShowInfoArguments
         return new self(array_shift($arguments));
     }
 
+    public function __construct(?string $file)
+    {
+        $this->guardUnusableFile($file);
+        $this->file = new SplFileInfo($file);
+    }
+
     public function getFile(): SplFileInfo
     {
-        if (is_null($this->file)) {
+        return $this->file;
+    }
+
+    private function guardUnusableFile(string $file): void
+    {
+        if (is_null($file)) {
             throw new MissingFileArgumentException();
         }
-        if (!file_exists($this->file)) {
-            throw new FileNotFoundException($this->file);
+        if (!file_exists($file)) {
+            throw new FileNotFoundException($file);
         }
-        if (!is_readable($this->file)) {
-            throw new FileNotReadableException($this->file);
+        if (!is_readable($file)) {
+            throw new FileNotReadableException($file);
         }
-
-        return new SplFileInfo($this->file);
     }
 }
diff --git a/src/RecursiveDocumentLocator.php b/src/RecursiveDocumentLocator.php
index 0a942bd..a7ca008 100644
--- a/src/RecursiveDocumentLocator.php
+++ b/src/RecursiveDocumentLocator.php
@@ -22,9 +22,19 @@ class RecursiveDocumentLocator
             RecursiveIteratorIterator::SELF_FIRST
         );
 
-        return collect($iterator)
-            ->filter(static fn(SplFileInfo $fileInfo) => $fileInfo->isFile())
-            ->filter(static fn(SplFileInfo $fileInfo) => preg_match('/.pdf$/i', $fileInfo->getBasename()))
-            ->map(fn(SplFileInfo $fileInfo) => $this->documentFactory->createDocument($fileInfo));
+        $documents = [];
+        foreach ($iterator as $file) {
+            if ($this->validate($file)) {
+                $documents[] = $this->documentFactory->createDocument($file);
+            }
+        }
+
+        return collect($documents);
+    }
+
+    private function validate(SplFileInfo $file): bool
+    {
+        return $file->isFile()
+            && preg_match('/.pdf$/i', $file->getBasename());
     }
 }