Add can_assemble property to PackageData

Signed-off-by: Ayan Sinha Mahapatra <ayansmahapatra@gmail.com>

Author: AyanSinhaMahapatra

src/packagedcode/models.py

@@ -741,6 +741,15 @@ def from_data(cls, package_data, package_only=False):
 
         return package_data
 
+    @property
+    def can_assemble(self):
+        from packagedcode import HANDLER_BY_DATASOURCE_ID
+        handler = HANDLER_BY_DATASOURCE_ID.get(self.datasource_id)
+        if issubclass(handler, NonAssemblableDatafileHandler):
+            return False
+
+        return True
+
     def normalize_extracted_license_statement(self):
         """
         Normalizes the extracted license statement to a readable

tests/packagedcode/test_package_models.py

@@ -90,6 +90,17 @@ def test_Package_simple(self):
         expected_loc = 'models/simple-expected.json'
         self.check_package_data(package_data, expected_loc, regen=REGEN_TEST_FIXTURES)
 
+    def test_PackageData_model_can_assemble(self):
+        package_jar = models.PackageData(
+            type='maven', name='this', version='23', datasource_id="java_jar",
+        )
+        package_pom = models.PackageData(
+            type='maven', name='this', version='23', datasource_id="maven_pom",
+        )
+
+        assert not package_jar.can_assemble
+        assert package_pom.can_assemble
+
     def test_Package_model_qualifiers_are_serialized_as_mappings(self):
         package = models.PackageData(
             type='maven', name='this', version='23', qualifiers=dict(this='that')