Merge pull request #907 from jdbi/type-missing-error

Improve error message thrown when a generic type cannot be inferred and you must #bindByType

core/src/main/java/org/jdbi/v3/core/statement/SqlStatement.java

@@ -18,6 +18,7 @@
 import java.io.InputStream;
 import java.io.Reader;
 import java.lang.reflect.Type;
+import java.lang.reflect.TypeVariable;
 import java.math.BigDecimal;
 import java.net.URL;
 import java.sql.Blob;
@@ -1067,7 +1068,18 @@ private Argument toArgument(Object value) {
 
     private Argument toArgument(Type type, Object value) {
         return getConfig(Arguments.class).findFor(type, value)
-                .orElseThrow(() -> new UnsupportedOperationException("No argument factory registered for '" + value + "' of type " + type));
+                .orElseThrow(() -> factoryNotFound(type, value));
+    }
+
+    private UnsupportedOperationException factoryNotFound(Type type, Object value) {
+        if (type instanceof Class<?>) { // not a ParameterizedType
+            final TypeVariable<?>[] params = ((Class<?>) type).getTypeParameters();
+            if (params.length > 0) {
+                return new UnsupportedOperationException("No type parameters found for erased type '" + type + Arrays.toString(params) +
+                        "'.  To bind a generic type, prefer using bindByType.");
+            }
+        }
+        return new UnsupportedOperationException("No argument factory registered for '" + value + "' of type " + type);
     }
 
     /**

core/src/test/java/org/jdbi/v3/core/argument/TestCollectionArguments.java

@@ -0,0 +1,38 @@
+/*
+ * 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 org.jdbi.v3.core.argument;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+import java.util.Collections;
+
+import org.jdbi.v3.core.Handle;
+import org.jdbi.v3.core.rule.PgDatabaseRule;
+import org.junit.Rule;
+import org.junit.Test;
+
+public class TestCollectionArguments {
+    @Rule
+    public PgDatabaseRule db = new PgDatabaseRule();
+
+    @Test
+    public void testBindTypeErased() throws Exception {
+        try (final Handle h = db.openHandle()) {
+            assertThatThrownBy( () ->
+                h.execute("SELECT * FROM something WHERE id = ANY(:ids)", Collections.singleton(1)))
+                    .isInstanceOf(UnsupportedOperationException.class)
+                    .hasMessageContaining("No type parameters found");
+        }
+    }
+}