feat: Add SuperObjectValue and unit test

src/main/java/com/google/api/generator/engine/ast/SuperObjectValue.java

@@ -0,0 +1,54 @@
+// Copyright 2020 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
+//
+//      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 com.google.api.generator.engine.ast;
+
+import com.google.auto.value.AutoValue;
+import com.google.common.base.Preconditions;
+
+@AutoValue
+public abstract class SuperObjectValue implements ObjectValue {
+  private static final String SUPER_VALUE = "super";
+
+  @Override
+  public abstract TypeNode type();
+
+  @Override
+  public String value() {
+    return SUPER_VALUE;
+  }
+
+  private static Builder builder() {
+    return new AutoValue_SuperObjectValue.Builder();
+  }
+
+  public static SuperObjectValue withType(TypeNode type) {
+    return builder().setType(type).build();
+  }
+
+  @AutoValue.Builder
+  abstract static class Builder {
+    abstract Builder setType(TypeNode type);
+
+    abstract SuperObjectValue autoBuild();
+
+    private SuperObjectValue build() {
+      SuperObjectValue superObjectValue = autoBuild();
+      Preconditions.checkState(
+          TypeNode.isReferenceType(superObjectValue.type()),
+          "super can only refer to object types");
+      return superObjectValue;
+    }
+  }
+}

src/test/java/com/google/api/generator/engine/ast/BUILD.bazel

@@ -25,6 +25,7 @@ TESTS = [
     "VariableTest",
     "VaporReferenceTest",
     "MethodInvocationExprTest",
+    "SuperObjectValueTest",
 ]
 
 filegroup(

src/test/java/com/google/api/generator/engine/ast/SuperObjectValueTest.java

@@ -0,0 +1,52 @@
+// Copyright 2020 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
+//
+//      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 com.google.api.generator.engine.ast;
+
+import static org.junit.Assert.assertThrows;
+
+import org.junit.Test;
+
+public class SuperObjectValueTest {
+
+  @Test
+  public void validSuperObjectValue_basic() {
+    VaporReference ref =
+        VaporReference.builder()
+            .setName("Student")
+            .setPakkage("com.google.example.examples.v1")
+            .build();
+    TypeNode typeNode = TypeNode.withReference(ref);
+    SuperObjectValue.withType(typeNode);
+    // No exception thrown, we're good.
+  }
+
+  @Test
+  public void invalidSuperObjectValue_nonReferenceType() {
+    assertThrows(
+        IllegalStateException.class,
+        () -> {
+          SuperObjectValue.withType(TypeNode.DOUBLE);
+        });
+  }
+
+  @Test
+  public void invalidSuperObjectValue_nullType() {
+    assertThrows(
+        IllegalStateException.class,
+        () -> {
+          SuperObjectValue.withType(TypeNode.NULL);
+        });
+  }
+}

src/test/java/com/google/api/generator/engine/writer/JavaWriterVisitorTest.java

@@ -43,6 +43,7 @@
 import com.google.api.generator.engine.ast.ScopeNode;
 import com.google.api.generator.engine.ast.Statement;
 import com.google.api.generator.engine.ast.StringObjectValue;
+import com.google.api.generator.engine.ast.SuperObjectValue;
 import com.google.api.generator.engine.ast.TernaryExpr;
 import com.google.api.generator.engine.ast.ThrowExpr;
 import com.google.api.generator.engine.ast.TryCatchStatement;
@@ -1654,6 +1655,36 @@ public void writeClassDefinition_statementsAndMethods() {
             "}\n"));
   }
 
+  @Test
+  public void writeSuperObjectValue_asscessFieldAndInvokeMethod() {
+    VaporReference ref =
+        VaporReference.builder().setName("Student").setPakkage("com.google.example.v1").build();
+    TypeNode classType = TypeNode.withReference(ref);
+    SuperObjectValue superObjectValue = SuperObjectValue.withType(classType);
+    ValueExpr superValueExpr = ValueExpr.withValue(superObjectValue);
+    Variable subVariable = Variable.builder().setName("name").setType(TypeNode.STRING).build();
+    VariableExpr superVariableExpr =
+        VariableExpr.builder()
+            .setVariable(subVariable)
+            .setExprReferenceExpr(superValueExpr)
+            .build();
+
+    MethodInvocationExpr methodExpr =
+        MethodInvocationExpr.builder()
+            .setMethodName("getName")
+            .setExprReferenceExpr(ValueExpr.withValue(superObjectValue))
+            .setReturnType(TypeNode.STRING)
+            .build();
+    AssignmentExpr assignmentExpr =
+        AssignmentExpr.builder()
+            .setVariableExpr(superVariableExpr)
+            .setValueExpr(methodExpr)
+            .build();
+
+    assignmentExpr.accept(writerVisitor);
+    assertThat(writerVisitor.write()).isEqualTo("super.name = super.getName()");
+  }
+
   private static String createLines(int numLines) {
     return new String(new char[numLines]).replace("\0", "%s");
   }