Code refactoring

Author: quen2404

src/main/java/com/qdesrame/openapi/diff/compare/OpenApiDiff.java

@@ -5,7 +5,6 @@
 import com.qdesrame.openapi.diff.utils.EndpointUtils;
 import io.swagger.v3.oas.models.OpenAPI;
 import io.swagger.v3.oas.models.PathItem;
-import io.swagger.v3.oas.models.Paths;
 import io.swagger.v3.oas.models.security.SecurityRequirement;
 import io.swagger.v3.parser.OpenAPIV3Parser;
 import io.swagger.v3.parser.core.models.AuthorizationValue;
@@ -19,6 +18,8 @@
 import java.util.Optional;
 import java.util.stream.Collectors;
 
+import static com.qdesrame.openapi.diff.compare.PathsDiff.valOrEmpty;
+
 public class OpenApiDiff {
 
     public static final String SWAGGER_VERSION_V2 = "2.0";
@@ -132,9 +133,7 @@ private OpenApiDiff(OpenAPI oldSpecOpenApi, OpenAPI newSpecOpenApi) {
     private ChangedOpenApi compare() {
         preProcess(oldSpecOpenApi);
         preProcess(newSpecOpenApi);
-        Paths oldPaths = oldSpecOpenApi.getPaths() == null? new Paths(): oldSpecOpenApi.getPaths();
-        Paths newPaths = newSpecOpenApi.getPaths() == null? new Paths(): newSpecOpenApi.getPaths();
-        Optional<ChangedPaths> paths = this.pathsDiff.diff(oldPaths, newPaths);
+        Optional<ChangedPaths> paths = this.pathsDiff.diff(valOrEmpty(oldSpecOpenApi.getPaths()), valOrEmpty(newSpecOpenApi.getPaths()));
         this.newEndpoints = new ArrayList<>();
         this.missingEndpoints = new ArrayList<>();
         this.changedOperations = new ArrayList<>();

src/main/java/com/qdesrame/openapi/diff/compare/PathsDiff.java

@@ -2,6 +2,7 @@
 
 import com.qdesrame.openapi.diff.model.ChangedPaths;
 import io.swagger.v3.oas.models.PathItem;
+import io.swagger.v3.oas.models.Paths;
 
 import java.util.*;
 import java.util.regex.Matcher;
@@ -53,4 +54,11 @@ public Optional<ChangedPaths> diff(final Map<String, PathItem> left, final Map<S
         });
         return changedPaths.isDiff() ? Optional.of(changedPaths) : Optional.empty();
     }
+
+    public static Paths valOrEmpty(Paths path) {
+        if (path == null) {
+            path = new Paths();
+        }
+        return path;
+    }
 }