feature: Allow Custom Modules to be configured with options

jsonschema-generator/src/main/java/com/github/victools/jsonschema/generator/CustomModule.java

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2025 Christian Scheer.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file 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.
+ */
+
+package com.github.victools.jsonschema.generator;
+
+import java.util.List;
+
+public interface CustomModule extends Module {
+    void setOptions(List<String> options);
+}

jsonschema-maven-plugin/README.md

@@ -223,7 +223,21 @@ To enable a custom module in the generation the following construct can be used:
 </configuration>
 ```
 Make sure your custom module is on the classpath and has a default constructor.
-It is not possible to configure options for custom modules.
+If your module implements `com.github.victools.jsonschema.generator.CustomModule`, you can configure options:
+```xml
+<configuration>
+    <classNames>com.myOrg.myApp.MyClass</classNames>
+    <modules>
+        <module>
+            <className>com.myOrg.myApp.CustomModule</className>
+            <options>
+                <option>MyOptionStringOne</option>
+                <option>MyOptionStringTwo</option>
+            </options>
+        </module>
+    </modules>
+</configuration>
+```
 
 ### Complete Example
 ```xml

jsonschema-maven-plugin/src/main/java/com/github/victools/jsonschema/plugin/maven/SchemaGeneratorMojo.java

@@ -18,6 +18,7 @@
 
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.github.victools.jsonschema.generator.CustomModule;
 import com.github.victools.jsonschema.generator.Module;
 import com.github.victools.jsonschema.generator.OptionPreset;
 import com.github.victools.jsonschema.generator.SchemaGenerator;
@@ -466,7 +467,7 @@ private void setOptions(SchemaGeneratorConfigBuilder configBuilder) {
     private void setModules(SchemaGeneratorConfigBuilder configBuilder) throws MojoExecutionException {
         for (GeneratorModule module : Util.nullSafe(this.modules)) {
             if (!Util.isNullOrEmpty(module.className)) {
-                this.addCustomModule(module.className, configBuilder);
+                this.addCustomModule(module, configBuilder);
             } else if (!Util.isNullOrEmpty(module.name)) {
                 this.addStandardModule(module, configBuilder);
             }
@@ -476,15 +477,22 @@ private void setModules(SchemaGeneratorConfigBuilder configBuilder) throws MojoE
     /**
      * Instantiate and apply the custom module with the given class name to the config builder.
      *
-     * @param moduleClassName Class name of the custom module to add.
+     * @param module Record in the modules section from the pom containing at least a name.
      * @param configBuilder The builder on which the module is added.
      * @throws MojoExecutionException When failing to instantiate the indicated module class.
      */
-    private void addCustomModule(String moduleClassName, SchemaGeneratorConfigBuilder configBuilder) throws MojoExecutionException {
+    private void addCustomModule(GeneratorModule module, SchemaGeneratorConfigBuilder configBuilder) throws MojoExecutionException {
+        String moduleClassName = module.className;
         this.getLog().debug("- Adding custom Module " + moduleClassName);
         try {
             Class<? extends Module> moduleClass = (Class<? extends Module>) this.loadClass(moduleClassName);
             Module moduleInstance = moduleClass.getConstructor().newInstance();
+            if (moduleInstance instanceof CustomModule) {
+                CustomModule customModule = (CustomModule) moduleInstance;
+                List<String> options = Util.nullSafe(module.options);
+                this.getLog().debug("- Adding custom Module options " + options);
+                customModule.setOptions(options);
+            }
             configBuilder.with(moduleInstance);
         } catch (ClassCastException | InstantiationException
                  | IllegalAccessException | NoSuchMethodException

jsonschema-maven-plugin/src/test/java/com/github/victools/jsonschema/plugin/maven/SchemaGeneratorMojoTest.java

@@ -57,7 +57,8 @@ public void setUp() throws Exception {
         "JakartaValidationModule",
         "Swagger15Module",
         "Swagger2Module",
-        "Complete"
+        "Complete",
+        "CustomModuleWithOptions"
     })
     public void testGeneration(String testCaseName) throws Exception {
         File testCaseLocation = new File("src/test/resources/reference-test-cases");

jsonschema-maven-plugin/src/test/java/com/github/victools/jsonschema/plugin/maven/TestCustomModule.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2025 Christian Scheer.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file 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.
+ */
+
+package com.github.victools.jsonschema.plugin.maven;
+
+import com.github.victools.jsonschema.generator.CustomModule;
+import com.github.victools.jsonschema.generator.SchemaGeneratorConfigBuilder;
+
+import java.util.List;
+
+public class TestCustomModule implements CustomModule {
+    private String skipFieldsStartingWith;
+
+    @Override
+    public void applyToConfigBuilder(SchemaGeneratorConfigBuilder builder) {
+        builder.forFields().withIgnoreCheck(field -> field.getName().startsWith(skipFieldsStartingWith));
+    }
+
+    @Override
+    public void setOptions(List<String> options) {
+        if (options.size() > 1) {
+            throw new IllegalArgumentException("More than one option specified");
+        }
+        this.skipFieldsStartingWith = options.get(0);
+    }
+}

jsonschema-maven-plugin/src/test/resources/reference-test-cases/CustomModuleWithOptions-pom.xml

@@ -0,0 +1,22 @@
+<project>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>com.github.victools</groupId>
+                <artifactId>jsonschema-maven-plugin</artifactId>
+                <configuration>
+                    <classNames>com.github.victools.jsonschema.plugin.maven.TestClass</classNames>
+                    <schemaFilePath>target/generated-test-sources/CustomModuleWithOptions</schemaFilePath>
+                    <modules>
+                        <module>
+                            <className>com.github.victools.jsonschema.plugin.maven.TestCustomModule</className>
+                            <options>
+                                <option>a</option>
+                            </options>
+                        </module>
+                    </modules>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+</project>

jsonschema-maven-plugin/src/test/resources/reference-test-cases/CustomModuleWithOptions-reference.json

@@ -0,0 +1,4 @@
+{
+  "$schema" : "http://json-schema.org/draft-07/schema#",
+  "type" : "object"
+}