Add ProtoMessageLiteValueProvider

common/src/main/java/dev/cel/common/values/BUILD.bazel

@@ -184,3 +184,21 @@ java_library(
         "@maven_android//:com_google_protobuf_protobuf_javalite",
     ],
 )
+
+java_library(
+    name = "proto_message_lite_value_provider",
+    srcs = ["ProtoMessageLiteValueProvider.java"],
+    tags = [
+    ],
+    deps = [
+        ":cel_value",
+        ":cel_value_provider",
+        ":proto_message_lite_value",
+        "//common/internal:cel_lite_descriptor_pool",
+        "//common/internal:default_lite_descriptor_pool",
+        "//protobuf:cel_lite_descriptor",
+        "@maven//:com_google_errorprone_error_prone_annotations",
+        "@maven//:com_google_guava_guava",
+        "@maven_android//:com_google_protobuf_protobuf_javalite",
+    ],
+)

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

@@ -0,0 +1,75 @@
+// Copyright 2025 Google LLC
+//
+// 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
+//
+//      https://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 dev.cel.common.values;
+
+import com.google.common.collect.ImmutableSet;
+import com.google.errorprone.annotations.Immutable;
+import com.google.protobuf.MessageLite;
+import dev.cel.common.internal.CelLiteDescriptorPool;
+import dev.cel.common.internal.DefaultLiteDescriptorPool;
+import dev.cel.protobuf.CelLiteDescriptor;
+import dev.cel.protobuf.CelLiteDescriptor.MessageLiteDescriptor;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+
+/**
+ * {@code ProtoMessageValueProvider} constructs new instances of protobuf lite-message given its
+ * fully qualified name and its fields to populate.
+ */
+@Immutable
+public class ProtoMessageLiteValueProvider implements CelValueProvider {
+  private final CelLiteDescriptorPool descriptorPool;
+  private final ProtoLiteCelValueConverter protoLiteCelValueConverter;
+
+  public ProtoLiteCelValueConverter getProtoLiteCelValueConverter() {
+    return protoLiteCelValueConverter;
+  }
+
+  @Override
+  public Optional<CelValue> newValue(String structType, Map<String, Object> fields) {
+    MessageLiteDescriptor descriptor = descriptorPool.findDescriptor(structType).orElse(null);
+    if (descriptor == null) {
+      return Optional.empty();
+    }
+
+    if (!fields.isEmpty()) {
+      // TODO: Add support for this
+      throw new UnsupportedOperationException(
+          "Message creation with prepopulated fields is not supported yet.");
+    }
+
+    MessageLite message = descriptor.newMessageBuilder().build();
+    return Optional.of(protoLiteCelValueConverter.fromProtoMessageToCelValue(structType, message));
+  }
+
+  public static ProtoMessageLiteValueProvider newInstance(CelLiteDescriptor... descriptors) {
+    return newInstance(ImmutableSet.copyOf(descriptors));
+  }
+
+  public static ProtoMessageLiteValueProvider newInstance(Set<CelLiteDescriptor> descriptors) {
+    DefaultLiteDescriptorPool descriptorPool =
+        DefaultLiteDescriptorPool.newInstance(ImmutableSet.copyOf(descriptors));
+    ProtoLiteCelValueConverter protoLiteCelValueConverter =
+        ProtoLiteCelValueConverter.newInstance(descriptorPool);
+    return new ProtoMessageLiteValueProvider(protoLiteCelValueConverter, descriptorPool);
+  }
+
+  private ProtoMessageLiteValueProvider(
+      ProtoLiteCelValueConverter protoLiteCelValueConverter, CelLiteDescriptorPool descriptorPool) {
+    this.protoLiteCelValueConverter = protoLiteCelValueConverter;
+    this.descriptorPool = descriptorPool;
+  }
+}

common/src/test/java/dev/cel/common/values/BUILD.bazel

@@ -28,6 +28,7 @@ java_library(
         "//common/values:cel_value",
         "//common/values:cel_value_provider",
         "//common/values:proto_message_lite_value",
+        "//common/values:proto_message_lite_value_provider",
         "//common/values:proto_message_value",
         "//common/values:proto_message_value_provider",
         "//testing:test_all_types_cel_java_proto3",

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

@@ -0,0 +1,54 @@
+// Copyright 2025 Google LLC
+//
+// 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
+//
+//      https://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 dev.cel.common.values;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.common.collect.ImmutableMap;
+import com.google.testing.junit.testparameterinjector.TestParameterInjector;
+import dev.cel.common.types.StructTypeReference;
+import dev.cel.expr.conformance.proto3.TestAllTypes;
+import dev.cel.expr.conformance.proto3.TestAllTypesCelDescriptor;
+import java.util.Optional;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+@RunWith(TestParameterInjector.class)
+public class ProtoMessageLiteValueProviderTest {
+  private static final ProtoMessageLiteValueProvider VALUE_PROVIDER =
+      ProtoMessageLiteValueProvider.newInstance(TestAllTypesCelDescriptor.getDescriptor());
+
+  @Test
+  public void newValue_unknownType_returnsEmpty() {
+    assertThat(VALUE_PROVIDER.newValue("unknownType", ImmutableMap.of())).isEmpty();
+  }
+
+  @Test
+  public void newValue_emptyFields_success() {
+    Optional<CelValue> value =
+        VALUE_PROVIDER.newValue("cel.expr.conformance.proto3.TestAllTypes", ImmutableMap.of());
+    ProtoMessageLiteValue protoMessageLiteValue = (ProtoMessageLiteValue) value.get();
+
+    assertThat(protoMessageLiteValue.value()).isEqualTo(TestAllTypes.getDefaultInstance());
+    assertThat(protoMessageLiteValue.isZeroValue()).isTrue();
+    assertThat(protoMessageLiteValue.celType())
+        .isEqualTo(StructTypeReference.create("cel.expr.conformance.proto3.TestAllTypes"));
+  }
+
+  @Test
+  public void getProtoLiteCelValueConverter() {
+    assertThat(VALUE_PROVIDER.getProtoLiteCelValueConverter()).isNotNull();
+  }
+}

common/values/BUILD.bazel

@@ -45,3 +45,8 @@ java_library(
     name = "proto_message_lite_value",
     exports = ["//common/src/main/java/dev/cel/common/values:proto_message_lite_value"],
 )
+
+java_library(
+    name = "proto_message_lite_value_provider",
+    exports = ["//common/src/main/java/dev/cel/common/values:proto_message_lite_value_provider"],
+)