#139 - Support types implementing interfaces with parameter type T etc (currently produces compile error)

Author: rbygrave

inject-generator/src/main/java/io/avaje/inject/generator/GenericType.java

@@ -42,6 +42,14 @@ static GenericType parse(String raw) {
     return new GenericTypeParser(raw).parse();
   }
 
+  /**
+   * Parse and return the main type if it contains a type parameter like {@code <T>}.
+   */
+  static String removeParameter(String raw) {
+    final GenericType type = parse(raw);
+    return type.hasParameter() ? type.getMainType() : raw;
+  }
+
   /**
    * Parse and return as GenericType or null if it is not generic.
    */
@@ -54,6 +62,21 @@ public String toString() {
     return raw != null ? raw : mainType + '<' + params + '>';
   }
 
+  /**
+   * Return true if the type contains a type parameter like {@code <T>}.
+   */
+  boolean hasParameter() {
+    if (mainType != null && mainType.indexOf('.') == -1) {
+      return true;
+    }
+    for (GenericType param : params) {
+      if (param.hasParameter()) {
+        return true;
+      }
+    }
+    return false;
+  }
+
   void addImports(Set<String> importTypes) {
     final String type = trimExtends();
     if (includeInImports(type)) {

inject-generator/src/main/java/io/avaje/inject/generator/GenericTypeParser.java

@@ -16,7 +16,6 @@ class GenericTypeParser {
   }
 
   GenericType parse() {
-
     int len = raw.length();
     for (int i = 0; i < len; i++) {
       char ch = raw.charAt(i);

inject-generator/src/main/java/io/avaje/inject/generator/TypeExtendsReader.java

@@ -124,6 +124,7 @@ private void readInterfaces(TypeElement type) {
       } else if (Constants.AUTO_CLOSEABLE.equals(rawType) || Constants.IO_CLOSEABLE.equals(rawType)) {
         closeable = true;
       } else {
+        rawType = GenericType.removeParameter(rawType);
         if (qualifierName == null) {
           final String iShortName = Util.shortName(rawType);
           if (beanSimpleName.endsWith(iShortName)) {

inject-generator/src/test/java/io/avaje/inject/generator/GenericTypeTest.java

@@ -8,24 +8,24 @@
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-public class GenericTypeTest {
+class GenericTypeTest {
 
   @Test
-  public void isGeneric() {
+  void isGeneric() {
 
     assertFalse(GenericType.isGeneric("java.lang.List"));
     assertTrue(GenericType.isGeneric("java.lang.List<Foo>"));
   }
 
   @Test
-  public void maybe() {
+  void maybe() {
 
     assertThat(GenericType.maybe("java.lang.List<Foo>").getMainType()).isEqualTo("java.lang.List");
     assertThat(GenericType.maybe("java.lang.List")).isNull();
   }
 
   @Test
-  public void parse() {
+  void parse() {
 
     GenericType type = new GenericTypeParser("my.exa.Repo<T,K>").parse();
 
@@ -36,8 +36,7 @@ public void parse() {
   }
 
   @Test
-  public void parse_withParams() {
-
+  void parse_withParams() {
 
     GenericType type = GenericType.parse("my.exa.Repo<my.d.Haz,java.lang.Long>");
 
@@ -48,7 +47,7 @@ public void parse_withParams() {
   }
 
   @Test
-  public void parse_withExtendsParams() {
+  void parse_withExtendsParams() {
 
     GenericType type = new GenericTypeParser("my.exa.Repo<? extends my.d.Haz,java.lang.Long>").parse();
 
@@ -58,9 +57,8 @@ public void parse_withExtendsParams() {
     assertThat(type.getParams().get(1).getMainType()).isEqualTo("java.lang.Long");
   }
 
-
   @Test
-  public void parse_withNestedParams() {
+  void parse_withNestedParams() {
 
     GenericType type = new GenericTypeParser("my.exa.Repo<my.a.Prov<my.b.Haz>,my.a.Key<java.util.UUID>>").parse();
 
@@ -76,13 +74,29 @@ public void parse_withNestedParams() {
   }
 
   @Test
-  public void shortName() {
+  void shortName() {
     assertThat(GenericType.parse("java.lang.List<Foo>").shortName()).isEqualTo("ListFoo");
     assertThat(GenericType.parse("java.lang.List<org.Foo<com.Bar>>").shortName()).isEqualTo("ListFooBar");
   }
 
   @Test
-  public void write() {
+  void hasParameter() {
+    assertThat(GenericType.parse("java.lang.List<T>").hasParameter()).isTrue();
+    assertThat(GenericType.parse("java.lang.List<org.Foo<TYPE>").hasParameter()).isTrue();
+    assertThat(GenericType.parse("java.lang.List<org.Foo<com.Bar>>").hasParameter()).isFalse();
+  }
+
+  @Test
+  void removeParameter() {
+    assertThat(GenericType.removeParameter("java.lang.List<T>")).isEqualTo("java.lang.List");
+    assertThat(GenericType.removeParameter("java.lang.List<org.Foo<T>>")).isEqualTo("java.lang.List");
+    assertThat(GenericType.removeParameter("java.lang.List<org.Foo<TYPE>>")).isEqualTo("java.lang.List");
+    assertThat(GenericType.removeParameter("face.FaceParam<T>")).isEqualTo("face.FaceParam");
+    assertThat(GenericType.removeParameter("java.lang.List<org.Foo<com.Bar>>")).isEqualTo("java.lang.List<org.Foo<com.Bar>>");
+  }
+
+  @Test
+  void write() {
 
     GenericType type = new GenericTypeParser("my.exa.Repo<my.a.Prov<my.b.Haz>,my.a.Key<java.util.UUID>>").parse();
 

inject-test/src/test/java/org/example/coffee/CoffeeMakerTest.java

@@ -9,9 +9,7 @@
 import org.example.coffee.list.Somei;
 import org.example.coffee.provider.AProv;
 import org.example.coffee.provider.AProvProvider;
-import org.example.iface.ConcreteExtend;
-import org.example.iface.IfaceExtend;
-import org.example.iface.IfaseBase;
+import org.example.iface.*;
 import org.example.inherit.*;
 import org.junit.jupiter.api.Test;
 
@@ -121,6 +119,22 @@ public void beanScope_all_includesGenericInterfaces() {
     }
   }
 
+  @Test
+  public void beanScope_all_interfaceWithParameter() {
+    try (BeanScope context = BeanScope.newBuilder().build()) {
+
+      final List<BeanEntry> beanEntries = context.all();
+
+      final BeanEntry hazRepo = beanEntries.stream()
+        .filter(e -> e.hasKey(MyParam.class))
+        .findFirst().orElse(null);
+
+      assertThat(hazRepo.keys())
+        .containsExactly(name(MyParam.class), name(IfaceParam.class), name(IfaceParamParent.class));
+    }
+  }
+
+
   @Test
   public void beanScope_all_provider() {
     try (BeanScope context = BeanScope.newBuilder().build()) {

inject-test/src/test/java/org/example/iface/IfaceParam.java

@@ -0,0 +1,9 @@
+package org.example.iface;
+
+/**
+ * Interface with type parameter T.
+ */
+public interface IfaceParam<T> extends IfaceParamParent {
+
+  T param();
+}

inject-test/src/test/java/org/example/iface/IfaceParamParent.java

@@ -0,0 +1,5 @@
+package org.example.iface;
+
+public interface IfaceParamParent {
+
+}

inject-test/src/test/java/org/example/iface/MyParam.java

@@ -0,0 +1,13 @@
+package org.example.iface;
+
+
+import jakarta.inject.Singleton;
+
+@Singleton
+public class MyParam<T> implements IfaceParam<T> {
+
+  @Override
+  public T param() {
+    return null;
+  }
+}