mvc: default value on @QueryParam/@CookieParam/@HeaderParam annotation

- fix #3761

Author: jknack

modules/jooby-apt/src/main/java/io/jooby/internal/apt/ParameterGenerator.java

@@ -326,6 +326,7 @@ protected String builtinType(
       boolean kt, AnnotationMirror annotation, TypeDefinition type, String name, boolean nullable) {
     if (BUILT_IN.stream().anyMatch(type::is)) {
       var paramSource = source(annotation);
+      var defaultValue = defaultValue(annotation);
       // look at named parameter
       if (type.isPrimitive()) {
         // like: .intValue
@@ -334,15 +335,27 @@ protected String builtinType(
             method,
             "(",
             CodeBlock.string(name),
-            paramSource,
+            paramSource.isEmpty() ? defaultValue : paramSource,
             ").",
             CodeBlock.type(kt, type.getName()).toLowerCase(),
             "Value()");
       } else if (type.is(String.class)) {
         var stringValue = nullable ? "valueOrNull" : "value";
-        // StringL: .value
+        if (paramSource.isEmpty() && !defaultValue.isEmpty()) {
+          // use non-null version bc there is a default value.
+          stringValue = "value";
+        }
+        // String: .value
         return CodeBlock.of(
-            "ctx.", method, "(", CodeBlock.string(name), paramSource, ").", stringValue, "()");
+            "ctx.",
+            method,
+            "(",
+            CodeBlock.string(name),
+            // Param Source doesn't support default value
+            paramSource.isEmpty() ? defaultValue : paramSource,
+            ").",
+            stringValue,
+            "()");
       } else {
         var toValue = nullable ? "toNullable" : "to";
         // Any other type: .to(UUID.class)
@@ -412,6 +425,14 @@ protected String source(AnnotationMirror annotation) {
     return "";
   }
 
+  protected String defaultValue(AnnotationMirror annotation) {
+    if (annotation.getAnnotationType().toString().startsWith("io.jooby.annotation")) {
+      var sources = findAnnotationValue(annotation, AnnotationSupport.VALUE);
+      return sources.isEmpty() ? "" : CodeBlock.of(", ", CodeBlock.string(sources.getFirst()));
+    }
+    return "";
+  }
+
   protected final String method;
   private final Set<String> annotations;
   private Set<String> typeRestrictions = Set.of(); // empty set means no restrictions by default

modules/jooby-apt/src/test/java/tests/ModuleCompilerTest.java

@@ -123,7 +123,7 @@ public void routesWithMimeTypes() throws Exception {
   public void routesWithParamLookup() throws Exception {
     new ProcessorRunner(new RouteWithParamLookup())
         .withRouter(
-            app -> {
+            (app, source) -> {
               MockRouter router = new MockRouter(app);
 
               Throwable t =

modules/jooby-apt/src/test/java/tests/i3761/C3761.java

@@ -0,0 +1,34 @@
+/*
+ * Jooby https://jooby.io
+ * Apache License Version 2.0 https://jooby.io/LICENSE.txt
+ * Copyright 2014 Edgar Espina
+ */
+package tests.i3761;
+
+import io.jooby.annotation.GET;
+import io.jooby.annotation.Path;
+import io.jooby.annotation.QueryParam;
+
+@Path("/3761")
+public class C3761 {
+
+  @GET("/number")
+  public int number(@QueryParam("5") int num) {
+    return num;
+  }
+
+  @GET("/unset")
+  public String unset(@QueryParam String unset) {
+    return unset;
+  }
+
+  @GET("/emptySet")
+  public String emptySet(@QueryParam("") String emptySet) {
+    return emptySet;
+  }
+
+  @GET("/stringVal")
+  public String string(@QueryParam("Hello") String stringVal) {
+    return stringVal;
+  }
+}

modules/jooby-apt/src/test/java/tests/i3761/Issue3761.java

@@ -0,0 +1,28 @@
+/*
+ * Jooby https://jooby.io
+ * Apache License Version 2.0 https://jooby.io/LICENSE.txt
+ * Copyright 2014 Edgar Espina
+ */
+package tests.i3761;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+import io.jooby.apt.ProcessorRunner;
+
+public class Issue3761 {
+  @Test
+  public void shouldGenerateDefaultValues() throws Exception {
+    new ProcessorRunner(new C3761())
+        .withSourceCode(
+            (source) -> {
+              assertTrue(source.contains("return c.number(ctx.query(\"num\", \"5\").intValue());"));
+              assertTrue(source.contains("return c.unset(ctx.query(\"unset\").valueOrNull());"));
+              assertTrue(
+                  source.contains("return c.emptySet(ctx.query(\"emptySet\", \"\").value());"));
+              assertTrue(
+                  source.contains("return c.string(ctx.query(\"stringVal\", \"Hello\").value());"));
+            });
+  }
+}