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+# ============LICENSE_START=======================================================
+# org.onap.vvp/image-scanner
+# ===================================================================
+# Copyright © 2017 AT&T Intellectual Property. All rights reserved.
+# ===================================================================
+#
+# Unless otherwise specified, all software contained herein is licensed
+# under the Apache License, Version 2.0 (the “License”);
+# you may not use this software except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#             http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+#
+#
+# Unless otherwise specified, all documentation contained herein is licensed
+# under the Creative Commons License, Attribution 4.0 Intl. (the “License”);
+# you may not use this documentation except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#             https://creativecommons.org/licenses/by/4.0/
+#
+# Unless required by applicable law or agreed to in writing, documentation
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# ============LICENSE_END============================================
+#
+# ECOMP is a trademark and service mark of AT&T Intellectual Property.
+#
+
+"""A single-dispatch mechanism using regular-expression matching.
+
+This API intentionally apes that of functools.singledispatch, for consistency.
+Where functools.singledispatch dispatches on the type of the first argument,
+regexdispatch dispatches on regex matching against the first argument.
+
+Match a given argument against a list of regular expressions; call the function
+corresponding to the first one that matches. If none match, call the method
+decorated with @regexdispatch.
+
+    @regexdispatch
+    def foo(bar, baz):
+        '''A function that will dispatch among a list of functions.'''
+        print("None of the regexes matched against bar")
+
+    @foo.register(r'[a-z]')
+    def _(bar, baz):
+        print("bar contains letters")
+
+    @foo.register(r'[0-9]')
+    def _(bar, baz):
+        print("bar contains numbers")
+
+"""
+import re
+from functools import update_wrapper
+
+
+class regexdispatch(object):
+
+    def __init__(self, prototype):
+        update_wrapper(self, prototype)
+        self.prototype = prototype
+        self.registry = []
+
+    def register(self, regex, fn=None):
+        def make_handler(fn):
+            fn.regex = re.compile(regex)
+            self.registry.append(fn)
+            return fn
+
+        if fn:
+            return make_handler(fn)
+        else:
+            return make_handler
+
+    def __call__(self, arg, *args, **kwargs):
+        """Dispatch to first handler function whose regex matches arg.
+
+        Pass through any extra provided arguments.
+        Pass named groups from handler's regex as keyword arguments.
+        Extra provided arguments override named groups from handler's regex.
+
+        """
+        for handler in self.registry:
+            mo = handler.regex.match(arg)
+            if mo is not None:
+                return handler(arg, *args, **dict(mo.groupdict(), **kwargs))
+        else:
+            return self.prototype(arg, *args, **kwargs)