diff --git a/yamllint/cli.py b/yamllint/cli.py
index 93cecc5..617064a 100644
--- a/yamllint/cli.py
+++ b/yamllint/cli.py
@@ -118,7 +118,7 @@ def run(argv=None):
         except EnvironmentError as e:
             print(e, file=sys.stderr)
             sys.exit(-1)
-        all_problems[file] = problems
+        all_problems[file] = [pb for pb in problems if pb]
 
     if args.stdin:
         # read yaml from stdin
@@ -127,7 +127,7 @@ def run(argv=None):
         except EnvironmentError as e:
             print(e, file=sys.stderr)
             sys.exit(-1)
-        all_problems['stdin'] = problems
+        all_problems['stdin'] = [pb for pb in problems if pb]
 
     max_level = show_all_problems(
         all_problems,
diff --git a/yamllint/format.py b/yamllint/format.py
index e98103a..4ddcc4c 100644
--- a/yamllint/format.py
+++ b/yamllint/format.py
@@ -17,29 +17,149 @@ def supports_color():
             hasattr(sys.stdout, 'isatty') and sys.stdout.isatty())
 
 
-class Format(object):
-    @staticmethod
-    def parsable(problem, filename):
-        return ('%(file)s:%(line)s:%(column)s: [%(level)s] %(message)s' %
-                {'file': filename,
-                 'line': problem.line,
-                 'column': problem.column,
-                 'level': problem.level,
-                 'message': problem.message})
-
-    @staticmethod
-    def standard(problem, filename):
-        line = '  %d:%d' % (problem.line, problem.column)
-        line += max(12 - len(line), 0) * ' '
+def run_on_gh():
+    """Return if the currnet job is on github."""
+    return 'GITHUB_ACTIONS' in os.environ and 'GITHUB_WORKFLOW' in os.environ
+
+
+class Formater(object):
+    """Any formater."""
+    # the formater name
+    name = ''
+
+    @classmethod
+    def get_formater(cls, name, no_warn):
+        """Return a formater instance."""
+
+        if name == 'auto':
+            if run_on_gh():
+                name = 'github'
+            elif supports_color():
+                name = 'colored'
+            else:
+                name = 'standard'
+
+        for formater in cls.__subclasses__():
+            if name == formater.name:
+                return formater(no_warn)
+        raise ValueError('unknown formater: %s' % name)
+
+    def __init__(self, no_warn):
+        """Setup the formater."""
+        self.no_warn = no_warn
+
+    def show_problems_for_all_files(self, all_problems):
+        """Show all problems of all files."""
+        raise NotImplementedError()
+
+    def show_problems_for_file(self, problems, file):
+        """Show all problems of a specific file."""
+        raise NotImplementedError()
+
+    def show_problem(self, problem, file):
+        """Show all problems of a specific file."""
+        raise NotImplementedError()
+
+
+class ParsableFormater(Formater):
+    """The parsable formater."""
+    name = 'parsable'
+
+    def show_problems_for_all_files(self, all_problems):
+        """Show all problems of all files."""
+        string = ''
+        for file, problems in all_problems.items():
+            string += self.show_problems_for_file(problems, file)
+        return string
+
+    def show_problems_for_file(self, problems, file):
+        """Show all problems of a specific file."""
+        string = ''
+        for problem in problems:
+            string += self.show_problem(problem, file)
+        return string
+
+    def show_problem(self, problem, file):
+        """Show all problems of a specific file."""
+        if self.no_warn and (problem.level != 'error'):
+            return ''
+        return (
+            '%(file)s:%(line)s:%(column)s: [%(level)s] %(message)s\n' %
+            {
+                'file': file,
+                'line': problem.line,
+                'column': problem.column,
+                'level': problem.level,
+                'message': problem.message
+            }
+        )
+
+
+class GithubFormater(Formater):
+    """The parsable formater."""
+    name = 'github'
+
+    def show_problems_for_all_files(self, all_problems):
+        """Show all problems of all files."""
+        string = ''
+        for file, problems in all_problems.items():
+            string += self.show_problems_for_file(problems, file)
+        return string
+
+    def show_problems_for_file(self, problems, file):
+        """Show all problems of a specific file."""
+        string = '::group::%s\n' % file
+        for problem in problems:
+            string += self.show_problem(problem, file)
+        if string == '::group::%s\n' % file:
+            return ''
+        return string + '::endgroup::\n\n'
+
+    def show_problem(self, problem, file):
+        """Show all problems of a specific file."""
+        if self.no_warn and (problem.level != 'error'):
+            return ''
+        line = '::'
         line += problem.level
-        line += max(21 - len(line), 0) * ' '
-        line += problem.desc
+        line += ' file=' + file + ','
+        line += 'line=' + format(problem.line) + ','
+        line += 'col=' + format(problem.column)
+        line += '::'
+        line += format(problem.line)
+        line += ':'
+        line += format(problem.column)
+        line += ' '
         if problem.rule:
-            line += '  (%s)' % problem.rule
+            line += '[' + problem.rule + '] '
+        line += problem.desc
+        line += '\n'
         return line
 
-    @staticmethod
-    def standard_color(problem, filename):
+
+class ColoredFormater(Formater):
+    """The parsable formater."""
+    name = 'colored'
+
+    def show_problems_for_all_files(self, all_problems):
+        """Show all problems of all files."""
+        string = ''
+        for file, problems in all_problems.items():
+            string += self.show_problems_for_file(problems, file)
+        return string
+
+    def show_problems_for_file(self, problems, file):
+        """Show all problems of a specific file."""
+        string = '\033[4m%s\033[0m\n' % file
+        for problem in problems:
+            string += self.show_problem(problem, file)
+        if string == '\033[4m%s\033[0m\n' % file:
+            return ''
+        return string + '\n'
+
+    def show_problem(self, problem, file):
+        """Show all problems of a specific file."""
+        if self.no_warn and (problem.level != 'error'):
+            return ''
         line = '  \033[2m%d:%d\033[0m' % (problem.line, problem.column)
         line += max(20 - len(line), 0) * ' '
         if problem.level == 'warning':
@@ -50,73 +170,58 @@ class Format(object):
         line += problem.desc
         if problem.rule:
             line += '  \033[2m(%s)\033[0m' % problem.rule
+        line += '\n'
         return line
 
-    @staticmethod
-    def github(problem, filename):
-        line = '::'
+
+class StandardFormater(Formater):
+    """The parsable formater."""
+    name = 'standard'
+
+    def show_problems_for_all_files(self, all_problems):
+        """Show all problems of all files."""
+        string = ''
+        for file, problems in all_problems.items():
+            string += self.show_problems_for_file(problems, file)
+        return string
+
+    def show_problems_for_file(self, problems, file):
+        """Show all problems of a specific file."""
+        string = file + '\n'
+        for problem in problems:
+            string += self.show_problem(problem, file)
+        if string == file + '\n':
+            return ''
+        return string + '\n'
+
+    def show_problem(self, problem, file):
+        """Show all problems of a specific file."""
+        if self.no_warn and (problem.level != 'error'):
+            return ''
+        line = '  %d:%d' % (problem.line, problem.column)
+        line += max(12 - len(line), 0) * ' '
         line += problem.level
-        line += ' file=' + filename + ','
-        line += 'line=' + format(problem.line) + ','
-        line += 'col=' + format(problem.column)
-        line += '::'
-        line += format(problem.line)
-        line += ':'
-        line += format(problem.column)
-        line += ' '
-        if problem.rule:
-            line += '[' + problem.rule + '] '
+        line += max(21 - len(line), 0) * ' '
         line += problem.desc
+        if problem.rule:
+            line += '  (%s)' % problem.rule
+        line += '\n'
         return line
 
 
-def show_problems(problems, file, args_format, no_warn):
-    first = True
-
-    if args_format == 'auto':
-        if ('GITHUB_ACTIONS' in os.environ and
-                'GITHUB_WORKFLOW' in os.environ):
-            args_format = 'github'
-        elif supports_color():
-            args_format = 'colored'
-
-    for problem in problems:
-        if no_warn and (problem.level != 'error'):
-            continue
-        if args_format == 'parsable':
-            print(Format.parsable(problem, file))
-        elif args_format == 'github':
-            if first:
-                print('::group::%s' % file)
-                first = False
-            print(Format.github(problem, file))
-        elif args_format == 'colored':
-            if first:
-                print('\033[4m%s\033[0m' % file)
-                first = False
-            print(Format.standard_color(problem, file))
-        else:
-            if first:
-                print(file)
-                first = False
-            print(Format.standard(problem, file))
-
-    if not first and args_format == 'github':
-        print('::endgroup::')
-
-    if not first and args_format != 'parsable':
-        print('')
-
-
-def max_level(problems):
+def max_level(all_problems):
     """Return the max level of all problems."""
-    return max(PROBLEM_LEVELS[problem.level] for problem in problems)
+    all_levels = [problem.level for problems in all_problems.values() for problem in problems]
+    if all_levels:
+        return max(map(lambda x: PROBLEM_LEVELS[x], all_levels))
+    return 0
 
 
 def show_all_problems(all_problems, args_format, no_warn):
     """Print all problems, return the max level."""
 
-    for file, problem in all_problems.items():
-        show_problems(problem, file, args_format, no_warn)
+    fmt = Formater.get_formater(args_format, no_warn)
+
+    print(fmt.show_problems_for_all_files(all_problems), end='')
 
     return max_level(all_problems)