[operators] feat: Add UnaryOperationExpr and unit test

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

@@ -53,6 +53,8 @@ public interface AstNodeVisitor {
 
   public void visit(ArithmeticOperationExpr arithmeticOperationExpr);
 
+  public void visit(UnaryOperationExpr unaryOperationExpr);
+
   /** =============================== COMMENT =============================== */
   public void visit(LineComment lineComment);
 

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

@@ -17,6 +17,7 @@
 import com.google.auto.value.AutoValue;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
+import java.util.EnumSet;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Objects;
@@ -66,6 +67,14 @@ public enum TypeKind {
       withReference(ConcreteReference.withClazz(Short.class));
 
   private static final Map<TypeNode, TypeNode> BOXED_TYPE_MAP = createBoxedTypeMap();
+  private static final EnumSet<TypeKind> NUMERIC_TYPE_SET =
+      EnumSet.of(
+          TypeKind.INT,
+          TypeKind.DOUBLE,
+          TypeKind.LONG,
+          TypeKind.SHORT,
+          TypeKind.FLOAT,
+          TypeKind.CHAR);
 
   public static final TypeNode VOID = builder().setTypeKind(TypeKind.VOID).build();
 
@@ -125,10 +134,18 @@ public static boolean isReferenceType(TypeNode type) {
         && !type.equals(TypeNode.NULL);
   }
 
+  public static boolean isBoxedType(TypeNode type) {
+    return BOXED_TYPE_MAP.containsValue(type);
+  }
+
   public boolean isPrimitiveType() {
     return isPrimitiveType(typeKind());
   }
 
+  public boolean isNumericType() {
+    return isNumericType(typeKind());
+  }
+
   public boolean isSupertypeOrEquals(TypeNode other) {
     boolean oneTypeIsNull = this.equals(TypeNode.NULL) ^ other.equals(TypeNode.NULL);
     return !isPrimitiveType()
@@ -200,6 +217,10 @@ private static boolean isPrimitiveType(TypeKind typeKind) {
     return !typeKind.equals(TypeKind.OBJECT);
   }
 
+  private static boolean isNumericType(TypeKind typeKind) {
+    return NUMERIC_TYPE_SET.contains(typeKind);
+  }
+
   private static Map<TypeNode, TypeNode> createBoxedTypeMap() {
     Map<TypeNode, TypeNode> map = new HashMap<>();
     map.put(TypeNode.INT, TypeNode.INT_OBJECT);

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

@@ -0,0 +1,102 @@
+// 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 UnaryOperationExpr implements OperationExpr {
+
+  public abstract Expr expr();
+
+  public abstract OperatorKind operatorKind();
+
+  public abstract TypeNode type();
+
+  public void accept(AstNodeVisitor visitor) {
+    visitor.visit(this);
+  }
+
+  public static UnaryOperationExpr postfixIncrementWithExpr(Expr expr) {
+    return builder()
+        .setExpr(expr)
+        .setOperatorKind(OperatorKind.UNARY_POST_INCREMENT)
+        .setType(expr.type())
+        .build();
+  }
+
+  public static UnaryOperationExpr logicalNotWithExpr(Expr expr) {
+    return builder()
+        .setOperatorKind(OperatorKind.UNARY_LOGICAL_NOT)
+        .setExpr(expr)
+        .setType(TypeNode.BOOLEAN)
+        .build();
+  }
+
+  public static Builder builder() {
+    return new AutoValue_UnaryOperationExpr.Builder();
+  }
+
+  @AutoValue.Builder
+  abstract static class Builder {
+
+    // private setter.
+    abstract Builder setExpr(Expr expr);
+
+    // private setter.
+    abstract Builder setOperatorKind(OperatorKind operator);
+
+    // private setter.
+    abstract Builder setType(TypeNode type);
+
+    abstract UnaryOperationExpr autoBuild();
+
+    private UnaryOperationExpr build() {
+      UnaryOperationExpr unaryOperationExpr = autoBuild();
+      TypeNode exprType = unaryOperationExpr.expr().type();
+      OperatorKind operator = unaryOperationExpr.operatorKind();
+      final String errorMsg =
+          String.format(
+              "Unary operator %s can not be applied to %s. ", operator, exprType.toString());
+
+      // Unary Operators can not be applied on Void type
+      Preconditions.checkState(
+          !exprType.equals(TypeNode.VOID) && !exprType.equals(TypeNode.NULL), errorMsg);
+
+      if (operator.equals(OperatorKind.UNARY_LOGICAL_NOT)) {
+        Preconditions.checkState(isValidLogicalNotType(exprType), errorMsg);
+      }
+
+      if (operator.equals(OperatorKind.UNARY_POST_INCREMENT)) {
+        Preconditions.checkState(isValidIncrementType(exprType), errorMsg);
+      }
+
+      return unaryOperationExpr;
+    }
+  }
+
+  private static boolean isValidLogicalNotType(TypeNode exprType) {
+    // Logical not (!) can only be applied on boolean/Boolean type
+    return exprType.equals(TypeNode.BOOLEAN) || exprType.equals(TypeNode.BOOLEAN_OBJECT);
+  }
+
+  private static boolean isValidIncrementType(TypeNode exprType) {
+    // Increment (++) can be applied on Numeric Type(int, double, float, long, short, char)
+    // and its boxed type (exclude Boolean)
+    return exprType.isNumericType()
+        || (TypeNode.isBoxedType(exprType) && !exprType.equals(TypeNode.BOOLEAN_OBJECT));
+  }
+}

src/main/java/com/google/api/generator/engine/writer/ImportWriterVisitor.java

@@ -46,6 +46,7 @@
 import com.google.api.generator.engine.ast.ThrowExpr;
 import com.google.api.generator.engine.ast.TryCatchStatement;
 import com.google.api.generator.engine.ast.TypeNode;
+import com.google.api.generator.engine.ast.UnaryOperationExpr;
 import com.google.api.generator.engine.ast.ValueExpr;
 import com.google.api.generator.engine.ast.VariableExpr;
 import com.google.api.generator.engine.ast.WhileStatement;
@@ -218,6 +219,11 @@ public void visit(ArithmeticOperationExpr arithmeticOperationExpr) {
     arithmeticOperationExpr.rhsExpr().accept(this);
   }
 
+  @Override
+  public void visit(UnaryOperationExpr unaryOperationExpr) {
+    unaryOperationExpr.expr().accept(this);
+  }
+
   /** =============================== STATEMENTS =============================== */
   @Override
   public void visit(ExprStatement exprStatement) {

src/main/java/com/google/api/generator/engine/writer/JavaWriterVisitor.java

@@ -47,6 +47,7 @@
 import com.google.api.generator.engine.ast.TryCatchStatement;
 import com.google.api.generator.engine.ast.TypeNode;
 import com.google.api.generator.engine.ast.TypeNode.TypeKind;
+import com.google.api.generator.engine.ast.UnaryOperationExpr;
 import com.google.api.generator.engine.ast.ValueExpr;
 import com.google.api.generator.engine.ast.Variable;
 import com.google.api.generator.engine.ast.VariableExpr;
@@ -394,6 +395,17 @@ public void visit(ArithmeticOperationExpr arithmeticOperationExpr) {
     arithmeticOperationExpr.rhsExpr().accept(this);
   }
 
+  @Override
+  public void visit(UnaryOperationExpr unaryOperationExpr) {
+    if (unaryOperationExpr.operatorKind().isPrefixOperator()) {
+      operator(unaryOperationExpr.operatorKind());
+      unaryOperationExpr.expr().accept(this);
+    } else {
+      unaryOperationExpr.expr().accept(this);
+      operator(unaryOperationExpr.operatorKind());
+    }
+  }
+
   /** =============================== STATEMENTS =============================== */
   @Override
   public void visit(ExprStatement exprStatement) {

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

@@ -34,6 +34,7 @@ TESTS = [
     "SuperObjectValueTest",
     "WhileStatementTest",
     "ArithmeticOperationExprTest",
+    "UnaryOperationExprTest",
 ]
 
 filegroup(

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

@@ -0,0 +1,95 @@
+// 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 UnaryOperationExprTest {
+  /** =============================== Logic Not Operation Expr =============================== */
+  @Test
+  public void logicalNotOperationExpr_validBasic() {
+    VariableExpr variableExpr =
+        VariableExpr.withVariable(
+            Variable.builder().setName("x").setType(TypeNode.BOOLEAN).build());
+    UnaryOperationExpr.logicalNotWithExpr(variableExpr);
+    // No exception thrown, we're good.
+  }
+
+  @Test
+  public void logicalNot_validBoxedType() {
+    VariableExpr variableExpr =
+        VariableExpr.withVariable(
+            Variable.builder().setName("x").setType(TypeNode.BOOLEAN_OBJECT).build());
+    UnaryOperationExpr.logicalNotWithExpr(variableExpr);
+    // No exception thrown, we're good.
+  }
+
+  @Test
+  public void logicalNot_invalidNumericType() {
+    VariableExpr variableExpr =
+        VariableExpr.withVariable(Variable.builder().setName("x").setType(TypeNode.INT).build());
+    assertThrows(
+        IllegalStateException.class, () -> UnaryOperationExpr.logicalNotWithExpr(variableExpr));
+  }
+
+  @Test
+  public void logicalNot_invalidReferenceType() {
+    VariableExpr variableExpr =
+        VariableExpr.withVariable(Variable.builder().setName("x").setType(TypeNode.STRING).build());
+    assertThrows(
+        IllegalStateException.class, () -> UnaryOperationExpr.logicalNotWithExpr(variableExpr));
+  }
+
+  /**
+   * =============================== Post Increment Operation Expr ===============================
+   */
+  @Test
+  public void postIncrement_validBasic() {
+    VariableExpr variableExpr =
+        VariableExpr.withVariable(Variable.builder().setName("x").setType(TypeNode.INT).build());
+    UnaryOperationExpr.postfixIncrementWithExpr(variableExpr);
+    // No exception thrown, we're good.
+  }
+
+  @Test
+  public void postIncrement_validBoxedType() {
+    VariableExpr variableExpr =
+        VariableExpr.withVariable(
+            Variable.builder().setName("x").setType(TypeNode.FLOAT_OBJECT).build());
+    UnaryOperationExpr.postfixIncrementWithExpr(variableExpr);
+    // No exception thrown, we're good.
+  }
+
+  @Test
+  public void postIncrement_invalidBoxedBooleanType() {
+    VariableExpr variableExpr =
+        VariableExpr.withVariable(
+            Variable.builder().setName("x").setType(TypeNode.BOOLEAN_OBJECT).build());
+    assertThrows(
+        IllegalStateException.class,
+        () -> UnaryOperationExpr.postfixIncrementWithExpr(variableExpr));
+  }
+
+  @Test
+  public void postIncrement_invalidReferenceType() {
+    VariableExpr variableExpr =
+        VariableExpr.withVariable(Variable.builder().setName("x").setType(TypeNode.STRING).build());
+    assertThrows(
+        IllegalStateException.class,
+        () -> UnaryOperationExpr.postfixIncrementWithExpr(variableExpr));
+  }
+}

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

@@ -44,6 +44,7 @@
 import com.google.api.generator.engine.ast.ThisObjectValue;
 import com.google.api.generator.engine.ast.ThrowExpr;
 import com.google.api.generator.engine.ast.TypeNode;
+import com.google.api.generator.engine.ast.UnaryOperationExpr;
 import com.google.api.generator.engine.ast.ValueExpr;
 import com.google.api.generator.engine.ast.VaporReference;
 import com.google.api.generator.engine.ast.Variable;
@@ -867,6 +868,32 @@ public void writeSynchronizedStatementImports_basicVariableExpr() {
             "import java.util.Map;\n\n"));
   }
 
+  @Test
+  public void writeUnaryOperationExprImports_LogicalNot() {
+    MethodInvocationExpr expr =
+        MethodInvocationExpr.builder()
+            .setStaticReferenceType(TypeNode.withReference(ConcreteReference.withClazz(Expr.class)))
+            .setMethodName("isEmpty")
+            .setReturnType(TypeNode.BOOLEAN)
+            .build();
+    UnaryOperationExpr unaryOperationExpr = UnaryOperationExpr.logicalNotWithExpr(expr);
+    unaryOperationExpr.accept(writerVisitor);
+    assertEquals(writerVisitor.write(), "import com.google.api.generator.engine.ast.Expr;\n\n");
+  }
+
+  @Test
+  public void writeUnaryOperationExprImports_PostIncrement() {
+    MethodInvocationExpr expr =
+        MethodInvocationExpr.builder()
+            .setStaticReferenceType(TypeNode.withReference(ConcreteReference.withClazz(Expr.class)))
+            .setMethodName("getNumber")
+            .setReturnType(TypeNode.INT)
+            .build();
+    UnaryOperationExpr unaryOperationExpr = UnaryOperationExpr.postfixIncrementWithExpr(expr);
+    unaryOperationExpr.accept(writerVisitor);
+    assertEquals(writerVisitor.write(), "import com.google.api.generator.engine.ast.Expr;\n\n");
+  }
+
   private static TypeNode createType(Class clazz) {
     return TypeNode.withReference(ConcreteReference.withClazz(clazz));
   }

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

@@ -54,6 +54,7 @@
 import com.google.api.generator.engine.ast.ThrowExpr;
 import com.google.api.generator.engine.ast.TryCatchStatement;
 import com.google.api.generator.engine.ast.TypeNode;
+import com.google.api.generator.engine.ast.UnaryOperationExpr;
 import com.google.api.generator.engine.ast.Value;
 import com.google.api.generator.engine.ast.ValueExpr;
 import com.google.api.generator.engine.ast.VaporReference;
@@ -1975,6 +1976,29 @@ public void writeSuperObjectValue_accessFieldAndInvokeMethod() {
     assertThat(writerVisitor.write()).isEqualTo("super.name = super.getName()");
   }
 
+  @Test
+  public void writeUnaryOperationExpr_postfixIncrement() {
+    VariableExpr variableExpr =
+        VariableExpr.withVariable(Variable.builder().setType(TypeNode.INT).setName("i").build());
+    UnaryOperationExpr postIncrementOperationExpr =
+        UnaryOperationExpr.postfixIncrementWithExpr(variableExpr);
+    postIncrementOperationExpr.accept(writerVisitor);
+    assertThat(writerVisitor.write()).isEqualTo("i++");
+  }
+
+  @Test
+  public void writeUnaryOperationExpr_logicalNot() {
+    MethodInvocationExpr methodInvocationExpr =
+        MethodInvocationExpr.builder()
+            .setMethodName("isEmpty")
+            .setReturnType(TypeNode.BOOLEAN)
+            .build();
+    UnaryOperationExpr logicalNotOperationExpr =
+        UnaryOperationExpr.logicalNotWithExpr(methodInvocationExpr);
+    logicalNotOperationExpr.accept(writerVisitor);
+    assertThat(writerVisitor.write()).isEqualTo("!isEmpty()");
+  }
+
   private static String createLines(int numLines) {
     return new String(new char[numLines]).replace("\0", "%s");
   }