implement config priorities

Author: frantuma

modules/swagger-codegen/src/main/java/io/swagger/codegen/v3/Codegen.java

@@ -1,6 +1,7 @@
 package io.swagger.codegen.v3;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -122,11 +123,20 @@ public static void main(String[] args) {
 
     public static List<CodegenConfig> getExtensions() {
         ServiceLoader<CodegenConfig> loader = ServiceLoader.load(CodegenConfig.class);
-        List<CodegenConfig> output = new ArrayList<CodegenConfig>();
-        for (CodegenConfig aLoader : loader) {
-            output.add(aLoader);
+        Map<String, CodegenConfig> output = new HashMap<>();
+
+        for (CodegenConfig config : loader) {
+            if (output.get(config.getName()) == null) {
+                output.put(config.getName(), config);
+            } else if (config.isPrivileged() && !output.get(config.getName()).isPrivileged()) {
+                output.put(config.getName(), config);
+            } else if (output.get(config.getName()).isPrivileged() && !config.isPrivileged()) {
+                // skip
+            } else if (config.getPriority() > output.get(config.getName()).getPriority()) {
+                output.put(config.getName(), config);
+            }
         }
-        return output;
+        return new ArrayList<>(output.values());
     }
 
     static void usage(Options options) {

modules/swagger-codegen/src/main/java/io/swagger/codegen/v3/CodegenConfig.java

@@ -255,4 +255,16 @@ public interface CodegenConfig {
     default boolean checkAliasModel() {
         return false;
     }
+
+    default boolean isPrivileged() {
+        return false;
+    }
+
+    default int getPriority() {
+        return Integer.MIN_VALUE;
+    }
+
+    default String getCodeName() {
+        return getName();
+    }
 }

modules/swagger-codegen/src/main/java/io/swagger/codegen/v3/CodegenConfigLoader.java

@@ -15,14 +15,25 @@ public static CodegenConfig forName(String name) {
         ServiceLoader<CodegenConfig> loader = load(CodegenConfig.class);
 
         StringBuilder availableConfigs = new StringBuilder();
-
+        CodegenConfig current = null;
         for (CodegenConfig config : loader) {
+
             if (config.getName().equals(name)) {
-                return config;
+                if (current == null) {
+                    current = config;
+                } else if (config.isPrivileged() && !current.isPrivileged()) {
+                    current = config;
+                } else if (current.isPrivileged() && !config.isPrivileged()) {
+                    // skip
+                } else if (config.getPriority() > current.getPriority()) {
+                    current = config;
+                }
             }
-
             availableConfigs.append(config.getName()).append("\n");
         }
+        if (current != null) {
+            return current;
+        }
 
         // else try to load directly
         try {

modules/swagger-codegen/src/main/java/io/swagger/codegen/v3/MetaGenerator.java

@@ -38,11 +38,20 @@ public static void main(String[] args) {
 
     public static List<CodegenConfig> getExtensions() {
         ServiceLoader<CodegenConfig> loader = ServiceLoader.load(CodegenConfig.class);
-        List<CodegenConfig> output = new ArrayList<CodegenConfig>();
+        Map<String, CodegenConfig> output = new HashMap<>();
+
         for (CodegenConfig config : loader) {
-            output.add(config);
+            if (output.get(config.getName()) == null) {
+                output.put(config.getName(), config);
+            } else if (config.isPrivileged() && !output.get(config.getName()).isPrivileged()) {
+                output.put(config.getName(), config);
+            } else if (output.get(config.getName()).isPrivileged() && !config.isPrivileged()) {
+                // skip
+            } else if (config.getPriority() > output.get(config.getName()).getPriority()) {
+                output.put(config.getName(), config);
+            }
         }
-        return output;
+        return new ArrayList<>(output.values());
     }
 
     static void usage(Options options) {