Fix JsonB generic generation errors

http-generator-core/src/main/java/io/avaje/http/generator/core/Append.java

@@ -8,7 +8,10 @@
  */
 public class Append {
 
+  private static final boolean DEBUG = Boolean.getBoolean("append.debug");
+
   private final Writer writer;
+  private final StringBuilder stringBuilder = new StringBuilder();
 
   public Append(Writer writer) {
     this.writer = writer;
@@ -17,6 +20,9 @@ public Append(Writer writer) {
   public Append append(String content) {
     try {
       writer.append(content);
+      if (DEBUG) {
+        stringBuilder.append(content);
+      }
       return this;
     } catch (IOException e) {
       throw new RuntimeException(e);
@@ -35,6 +41,9 @@ public void close() {
   public Append eol() {
     try {
       writer.append("\n");
+      if (DEBUG) {
+        stringBuilder.append("\n");
+      }
       return this;
     } catch (IOException e) {
       throw new RuntimeException(e);
@@ -48,4 +57,8 @@ public Append append(String format, Object... args) {
     return append(String.format(format, args));
   }
 
+  @Override
+  public String toString() {
+    return stringBuilder.toString();
+  }
 }

http-generator-core/src/main/java/io/avaje/http/generator/core/JsonBUtil.java

@@ -86,12 +86,14 @@ public static void writeJsonbType(UType type, Append writer) {
   static void writeType(UType type, Append writer) {
     if (type.isGeneric()) {
       final var params =
-          type.importTypes().stream()
-              .skip(1)
+          type.params().stream()
               .map(Util::shortName)
+              .map(s -> "?".equals(s) ? "Object" : s)
               .collect(Collectors.joining(".class, "));
 
-      writer.append("Types.newParameterizedType(%s.class, %s.class))", Util.shortName(type.mainType()), params);
+      writer.append(
+          "Types.newParameterizedType(%s.class, %s.class))",
+          Util.shortName(type.mainType()), params);
     } else {
       writer.append("%s.class)", Util.shortName(type.mainType()));
     }

http-generator-core/src/main/java/io/avaje/http/generator/core/UType.java

@@ -1,6 +1,9 @@
 package io.avaje.http.generator.core;
 
 import javax.lang.model.type.TypeMirror;
+
+import static java.util.stream.Collectors.toList;
+
 import java.util.*;
 
 public interface UType {
@@ -69,6 +72,13 @@ default UType paramRaw() {
     return null;
   }
 
+  /**
+   * Return the first generic parameter.
+   */
+  default List<String> params() {
+    return List.of();
+  }
+
   /**
    * Return the raw type.
    */
@@ -275,7 +285,7 @@ public String shortType() {
 
     @Override
     public String shortName() {
-      return shortName.replace(".", "$");
+      return shortName.replace(".", "$").replace("?", "Object");
     }
 
     @Override
@@ -293,6 +303,11 @@ public String param1() {
       return allTypes.size() < 3 ? null : allTypes.get(2);
     }
 
+    @Override
+    public List<String> params() {
+      return allTypes.stream().skip(1).collect(toList());
+    }
+
     @Override
     public UType paramRaw() {
       return rawParamType;

http-generator-core/src/test/java/io/avaje/http/generator/core/JsonBUtilTest.java

@@ -0,0 +1,46 @@
+package io.avaje.http.generator.core;
+
+import org.junit.jupiter.api.Test;
+
+import java.io.StringWriter;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class JsonBUtilTest {
+
+  @Test
+  void writeType() {
+    UType uType = UType.parse("my.pack.Foo");
+    var sw = new StringWriter();
+    JsonBUtil.writeType(uType, new Append(sw));
+
+    assertThat(sw.toString()).isEqualTo("Foo.class)");
+  }
+
+  @Test
+  void writeType_generic() {
+    UType uType = UType.parse("my.pack.Some<java.lang.String>");
+    var sw = new StringWriter();
+    JsonBUtil.writeType(uType, new Append(sw));
+
+    assertThat(sw.toString()).isEqualTo("Types.newParameterizedType(Some.class, String.class))");
+  }
+
+  @Test
+  void writeType_genericWithWildcard() {
+    UType uType = UType.parse("my.pack.Some<java.lang.String, ?>");
+    var sw = new StringWriter();
+    JsonBUtil.writeType(uType, new Append(sw));
+
+    assertThat(sw.toString()).isEqualTo("Types.newParameterizedType(Some.class, String.class, Object.class))");
+  }
+
+  @Test
+  void writeType_genericWithMultiple() {
+    UType uType = UType.parse("my.pack.Some<java.lang.String, my.other.Foo>");
+    var sw = new StringWriter();
+    JsonBUtil.writeType(uType, new Append(sw));
+
+    assertThat(sw.toString()).isEqualTo("Types.newParameterizedType(Some.class, String.class, Foo.class))");
+  }
+}

tests/test-javalin-jsonb/src/main/java/org/example/myapp/web/test/GenericController.java

@@ -0,0 +1,27 @@
+package org.example.myapp.web.test;
+
+import io.avaje.http.api.Controller;
+import io.avaje.http.api.Get;
+import io.avaje.http.api.Path;
+import io.avaje.jsonb.Json;
+
+@Path("/jsonbGeneric")
+@Controller
+public class GenericController {
+
+  @Json
+  public static class Data<T> {}
+
+  @Json
+  public static class Data2<T, T2> {}
+
+  @Get("single")
+  Data<String> getData() {
+    return null;
+  }
+
+  @Get("double")
+  Data2<String, ?> getData2() {
+    return null;
+  }
+}