Add value type parameter in StructValue

PiperOrigin-RevId: 904602834

Author: l46kok

common/src/main/java/dev/cel/common/values/ProtoMessageLiteValue.java

@@ -35,7 +35,7 @@
  */
 @AutoValue
 @Immutable
-public abstract class ProtoMessageLiteValue extends StructValue<String> {
+public abstract class ProtoMessageLiteValue extends StructValue<String, MessageLite> {
 
   @Override
   public abstract MessageLite value();

common/src/main/java/dev/cel/common/values/ProtoMessageValue.java

@@ -28,7 +28,7 @@
 /** ProtoMessageValue is a struct value with protobuf support. */
 @AutoValue
 @Immutable
-public abstract class ProtoMessageValue extends StructValue<String> {
+public abstract class ProtoMessageValue extends StructValue<String, Message> {
 
   @Override
   public abstract Message value();

common/src/main/java/dev/cel/common/values/StructValue.java

@@ -19,13 +19,20 @@
 /**
  * StructValue is a representation of a structured object with typed properties.
  *
- * <p>Users may extend from this class to provide a custom struct that CEL can understand (ex:
- * POJOs). Custom struct implementations must provide all functionalities denoted in the CEL
- * specification, such as field selection, presence testing and new object creation.
+ * <p>Users may extend from this class to provide a custom struct that CEL can understand by
+ * wrapping a native Java object (e.g., a POJO or a Map). Custom struct implementations must provide
+ * all functionalities denoted in the CEL specification, such as field selection, presence testing
+ * and new object creation.
  *
  * <p>For an expression `e` selecting a field `f`, `e.f` must throw an exception if `f` does not
  * exist in the struct (i.e: hasField returns false). If the field exists but is not set, the
  * implementation should return an appropriate default value based on the struct's semantics.
+ *
+ * @param <F> The type of the field identifier (typically String).
+ * @param <V> The type of the wrapped native object.
  */
 @Immutable
-public abstract class StructValue<T> extends CelValue implements SelectableValue<T> {}
+public abstract class StructValue<F, V> extends CelValue implements SelectableValue<F> {
+  @Override
+  public abstract V value();
+}

common/src/test/java/dev/cel/common/values/OptionalValueTest.java

@@ -141,7 +141,7 @@ public void celTypeTest() {
   }
 
   @SuppressWarnings("Immutable") // Test only
-  private static class CelCustomStruct extends StructValue<String> {
+  private static class CelCustomStruct extends StructValue<String, Long> {
     private final long data;
 
     @Override

common/src/test/java/dev/cel/common/values/StructValueTest.java

@@ -70,15 +70,15 @@ public Optional<CelType> findType(String typeName) {
   public void emptyStruct() {
     CelCustomStructValue celCustomStruct = new CelCustomStructValue(0);
 
-    assertThat(celCustomStruct.value()).isEqualTo(celCustomStruct);
+    assertThat(celCustomStruct.value().getData()).isEqualTo(0L);
     assertThat(celCustomStruct.isZeroValue()).isTrue();
   }
 
   @Test
   public void constructStruct() {
     CelCustomStructValue celCustomStruct = new CelCustomStructValue(5);
 
-    assertThat(celCustomStruct.value()).isEqualTo(celCustomStruct);
+    assertThat(celCustomStruct.value().getData()).isEqualTo(5L);
     assertThat(celCustomStruct.isZeroValue()).isFalse();
   }
 
@@ -122,9 +122,9 @@ public void evaluate_usingCustomClass_createNewStruct() throws Exception {
             .build();
     CelAbstractSyntaxTree ast = cel.compile("custom_struct{data: 50}").getAst();
 
-    CelCustomStructValue result = (CelCustomStructValue) cel.createProgram(ast).eval();
+    CustomPojo result = (CustomPojo) cel.createProgram(ast).eval();
 
-    assertThat(result.data).isEqualTo(50);
+    assertThat(result.getData()).isEqualTo(50);
   }
 
   @Test
@@ -142,7 +142,7 @@ public void evaluate_usingCustomClass_asVariable() throws Exception {
         (CelCustomStructValue)
             cel.createProgram(ast).eval(ImmutableMap.of("a", new CelCustomStructValue(10)));
 
-    assertThat(result.data).isEqualTo(10);
+    assertThat(result.value().getData()).isEqualTo(10);
   }
 
   @Test
@@ -197,19 +197,45 @@ public void evaluate_usingMultipleProviders_selectFieldFromCustomClass() throws
   // TODO: Bring back evaluate_usingMultipleProviders_selectFieldFromProtobufMessage
   // once planner is exposed from factory
 
+  private static class CustomPojo implements SelectableValue<String> {
+    private final long data;
+
+    CustomPojo(long data) {
+      this.data = data;
+    }
+
+    long getData() {
+      return data;
+    }
+
+    @Override
+    public Object select(String field) {
+      return find(field)
+          .orElseThrow(() -> new IllegalArgumentException("Invalid field name: " + field));
+    }
+
+    @Override
+    public Optional<Object> find(String field) {
+      if (field.equals("data")) {
+        return Optional.of(data);
+      }
+      return Optional.empty();
+    }
+  }
+
   @SuppressWarnings("Immutable") // Test only
-  private static class CelCustomStructValue extends StructValue<String> {
+  private static class CelCustomStructValue extends StructValue<String, CustomPojo> {
 
-    private final long data;
+    private final CustomPojo pojo;
 
     @Override
-    public CelCustomStructValue value() {
-      return this;
+    public CustomPojo value() {
+      return pojo;
     }
 
     @Override
     public boolean isZeroValue() {
-      return data == 0;
+      return pojo.getData() == 0;
     }
 
     @Override
@@ -226,7 +252,7 @@ public Object select(String field) {
     @Override
     public Optional<Object> find(String field) {
       if (field.equals("data")) {
-        return Optional.of(value().data);
+        return Optional.of(pojo.getData());
       }
 
       return Optional.empty();
@@ -237,7 +263,7 @@ private CelCustomStructValue(Map<String, Object> fields) {
     }
 
     private CelCustomStructValue(long data) {
-      this.data = data;
+      this.pojo = new CustomPojo(data);
     }
   }
 }

runtime/src/main/java/dev/cel/runtime/planner/EvalCreateStruct.java

@@ -87,9 +87,8 @@ Object evalInternal(GlobalResolver resolver, ExecutionFrame frame) {
             .newValue(structType.name(), Collections.unmodifiableMap(fieldValues))
             .orElseThrow(
                 () -> new IllegalArgumentException("Type name not found: " + structType.name()));
-
     if (value instanceof StructValue) {
-      return ((StructValue<?>) value).value();
+      return ((StructValue<?, ?>) value).value();
     }
 
     return value;