Update oneOf generator

Author: Kaycell

.generator/src/generator/templates/modelOneOf.j2

@@ -139,11 +139,23 @@ public class {{ name }} extends AbstractOpenApiSchema {
         super("oneOf", Boolean.{{ "TRUE" if model.nullable else "FALSE" }});
     }
 
+    {%- set constructor_sigs = [] %}
     {%- for oneOf in model.oneOf %}
-    public {{ name }}({{ get_type(oneOf) }} o) {
+    {%- set param_type = get_type(oneOf) %}
+    {%- set unparam_type = param_type|un_parameterize_type %}
+    {%- if unparam_type in constructor_sigs %}
+    public static {{ name }} from{{ param_type.replace('<', '').replace('>', '').replace(' ', '').replace(',', '') }}({{ param_type }} o) {
+        {{ name }} instance = new {{ name }}();
+        instance.setActualInstance(o);
+        return instance;
+    }
+    {%- else %}
+    {%- set _ = constructor_sigs.append(unparam_type) %}
+    public {{ name }}({{ param_type }} o) {
         super("oneOf", Boolean.{{ "TRUE" if model.nullable else "FALSE" }});
         setActualInstance(o);
     }
+    {%- endif %}
     {%- endfor  %}
 
     static {
@@ -204,9 +216,16 @@ public class {{ name }} extends AbstractOpenApiSchema {
         return super.getActualInstance();
     }
 
+    {%- set method_names = [] %}
     {%- for oneOf in model.oneOf %}
     {%- set dataType = get_type(oneOf) %}
     {%- set unParameterizedDataType = get_type(oneOf)|un_parameterize_type %}
+    {%- set method_name = "get" + unParameterizedDataType %}
+    {%- if method_name in method_names %}
+    {%- set safe_type = dataType.replace('<', '').replace('>', '').replace(' ', '').replace(',', '') %}
+    {%- set method_name = "get" + safe_type %}
+    {%- endif %}
+    {%- set _ = method_names.append(method_name) %}
 
     /**
      * Get the actual instance of `{{ dataType|escape_html }}`. If the actual instance is not `{{ dataType|escape_html }}`,
@@ -215,7 +234,7 @@ public class {{ name }} extends AbstractOpenApiSchema {
      * @return The actual instance of `{{ dataType|escape_html }}`
      * @throws ClassCastException if the instance is not `{{ dataType|escape_html }}`
      */
-    public {{ dataType }} get{{ unParameterizedDataType }}() throws ClassCastException {
+    public {{ dataType }} {{ method_name }}() throws ClassCastException {
         return ({{ dataType }})super.getActualInstance();
     }