make ComparableExpressions sortable

api/src/main/java/jakarta/data/Order.java

@@ -140,7 +140,7 @@ public List<Sort<? super T>> sorts() {
     @Override
     public boolean equals(Object other) {
         return this == other
-                || other instanceof Order s && sorts.equals(s.sorts);
+            || other instanceof Order<?> s && sorts.equals(s.sorts);
     }
 
     /**
@@ -164,7 +164,6 @@ public Iterator<Sort<? super T>> iterator() {
         return sorts.iterator();
     }
 
-
     /**
      * Textual representation of this instance, including the result of invoking
      * {@link Sort#toString()} on each member of the sort criteria, in order of

api/src/main/java/jakarta/data/Sortable.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2026 Contributors to the Eclipse Foundation
+ *
+ * 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.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package jakarta.data;
+
+/**
+ * An entity attribute or expression that can be used to sort query results.
+ *
+ * @since 1.1
+ * @param <T> the entity type
+ */
+public interface Sortable<T> {
+
+    /**
+     * Obtain an ascending {@linkplain Sort sorting criterion} based on
+     * this entity attribute or expression.
+     *
+     * @return the sorting criterion.
+     */
+    default Sort<T> asc() {
+        return Sort.asc(this);
+    }
+
+    /**
+     * Obtain a descending {@linkplain Sort sorting criterion} based on
+     * this entity attribute or expression.
+     *
+     * @return the sorting criterion.
+     */
+    default Sort<T> desc() {
+        return Sort.desc(this);
+    }
+}

api/src/main/java/jakarta/data/expression/ComparableExpression.java

@@ -17,6 +17,7 @@
  */
 package jakarta.data.expression;
 
+import jakarta.data.Sortable;
 import jakarta.data.constraint.Between;
 import jakarta.data.constraint.GreaterThan;
 import jakarta.data.constraint.AtLeast;
@@ -44,7 +45,7 @@
  * @since 1.1
  */
 public interface ComparableExpression<T, V extends Comparable<?>>
-        extends Expression<T, V> {
+        extends Expression<T, V>, Sortable<T> {
 
     /**
      * <p>Obtains a {@link Restriction} that requires that this expression

api/src/main/java/jakarta/data/metamodel/SortableAttribute.java

@@ -17,7 +17,7 @@
  */
 package jakarta.data.metamodel;
 
-import jakarta.data.Sort;
+import jakarta.data.Sortable;
 import jakarta.data.messages.Messages;
 
 /**
@@ -38,27 +38,7 @@
  *
  * @param <T> entity class of the static metamodel.
  */
-public interface SortableAttribute<T> extends Attribute<T> {
-
-    /**
-     * Obtain a request for an ascending {@link Sort} based on the entity
-     * attribute.
-     *
-     * @return a request for an ascending sort on the entity attribute.
-     */
-    default Sort<T> asc() {
-        return Sort.asc(name());
-    }
-
-    /**
-     * Obtain a request for a descending {@link Sort} based on the entity
-     * attribute.
-     *
-     * @return a request for a descending sort on the entity attribute.
-     */
-    default Sort<T> desc() {
-        return Sort.desc(name());
-    }
+public interface SortableAttribute<T> extends Attribute<T>, Sortable<T> {
 
     /**
      * <p>Creates a static metamodel {@code SortableAttribute} representing the

api/src/main/java/jakarta/data/metamodel/TextAttribute.java

@@ -28,17 +28,6 @@
  */
 public interface TextAttribute<T> extends ComparableAttribute<T, String>, TextExpression<T> {
 
-    /**
-     * Obtain a request for an ascending, case-insensitive {@link Sort} based on
-     * the entity attribute.
-     *
-     * @return a request for an ascending, case-insensitive sort on the entity
-     * attribute.
-     */
-    default Sort<T> ascIgnoreCase() {
-        return Sort.ascIgnoreCase(name());
-    }
-
     /**
      * Returns {@code String.class} as the entity attribute type for text
      * attributes.
@@ -51,6 +40,17 @@ default Class<String> type() {
         return String.class;
     }
 
+    /**
+     * Obtain a request for an ascending, case-insensitive {@link Sort} based on
+     * the entity attribute.
+     *
+     * @return a request for an ascending, case-insensitive sort on the entity
+     * attribute.
+     */
+    default Sort<T> ascIgnoreCase() {
+        return Sort.ascIgnoreCase(this);
+    }
+
     /**
      * Obtain a request for a descending, case insensitive {@link Sort} based on
      * the entity attribute.
@@ -59,7 +59,7 @@ default Class<String> type() {
      * attribute.
      */
     default Sort<T> descIgnoreCase() {
-        return Sort.descIgnoreCase(name());
+        return Sort.descIgnoreCase(this);
     }
 
     /**

api/src/test/java/jakarta/data/SortTest.java

@@ -34,17 +34,17 @@ class SortTest {
     @DisplayName("Should throw NullPointerException when one of the properties are null")
     void shouldReturnErrorWhenPropertyDirectionNull() {
         assertThatNullPointerException().isThrownBy(() ->
-                Sort.of(null, null, false));
+                Sort.of((String) null, null, false));
         assertThatNullPointerException().isThrownBy(() ->
                 Sort.of(NAME, null, true));
         assertThatNullPointerException().isThrownBy(() ->
-                Sort.of(null, Direction.ASC, false));
+                Sort.of((String) null, Direction.ASC, false));
         assertThatNullPointerException().isThrownBy(() ->
-                Sort.of(null, null, false, Sort.Nulls.FIRST));
+                Sort.of((String) null, null, false, Sort.Nulls.FIRST));
         assertThatNullPointerException().isThrownBy(() ->
                 Sort.of(NAME, null, true, Sort.Nulls.LAST));
         assertThatNullPointerException().isThrownBy(() ->
-                Sort.of(null, Direction.ASC, false, Sort.Nulls.UNSPECIFIED));
+                Sort.of((String) null, Direction.ASC, false, Sort.Nulls.UNSPECIFIED));
         assertThatNullPointerException().isThrownBy(() ->
         Sort.of(NAME, Direction.ASC, false, null));
     }