feat: add reserved language keywords

Author: miraleung

src/main/java/com/google/api/generator/engine/lexicon/BUILD.bazel

@@ -0,0 +1,16 @@
+package(default_visibility = ["//visibility:public"])
+
+filegroup(
+    name = "lexicon_files",
+    srcs = glob(["*.java"]),
+)
+
+java_library(
+    name = "lexicon",
+    srcs = [
+        ":lexicon_files",
+    ],
+    deps = [
+        "@com_google_guava_guava__com_google_api_codegen//jar",
+    ],
+)

src/main/java/com/google/api/generator/engine/lexicon/Keyword.java

@@ -0,0 +1,64 @@
+package com.google.api.generator.engine.lexicon;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.collect.ImmutableList;
+
+public class Keyword {
+  @VisibleForTesting
+  static final ImmutableList<String> KEYWORDS =
+      ImmutableList.of(
+          "abstract",
+          "continue",
+          "for",
+          "new",
+          "switch",
+          "assert",
+          "default",
+          "if",
+          "package",
+          "synchronized",
+          "boolean",
+          "do",
+          "goto",
+          "private",
+          "this",
+          "break",
+          "double",
+          "implements",
+          "protected",
+          "throw",
+          "byte",
+          "else",
+          "import",
+          "public",
+          "throws",
+          "case",
+          "enum",
+          "instanceof",
+          "return",
+          "transient",
+          "catch",
+          "extends",
+          "int",
+          "short",
+          "try",
+          "char",
+          "final",
+          "interface",
+          "static",
+          "void",
+          "class",
+          "finally",
+          "long",
+          "strictfp",
+          "volatile",
+          "const",
+          "float",
+          "native",
+          "super",
+          "while");
+
+  public static boolean isKeyword(String s) {
+    return KEYWORDS.contains(s);
+  }
+}

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

@@ -0,0 +1,15 @@
+package(default_visibility = ["//visibility:public"])
+
+TESTS = [
+    "KeywordTest",
+]
+
+[java_test(
+    name = test_name,
+    srcs = ["{0}.java".format(test_name)],
+    test_class = "com.google.api.generator.engine.lexicon.{0}".format(test_name),
+    deps = [
+        "//src/main/java/com/google/api/generator/engine/lexicon",
+        "@com_google_truth_truth//jar",
+    ],
+) for test_name in TESTS]

src/test/java/com/google/api/generator/engine/lexicon/KeywordTest.java

@@ -0,0 +1,29 @@
+package com.google.api.generator.engine.lexicon;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import org.junit.Test;
+
+public class KeywordTest {
+  @Test
+  public void keywordTest() {
+    // Modifiers.
+    assertThat(Keyword.isKeyword("static")).isTrue();
+    assertThat(Keyword.isKeyword("private")).isTrue();
+
+    // Other semantic blocks..
+    assertThat(Keyword.isKeyword("throws")).isTrue();
+    assertThat(Keyword.isKeyword("try")).isTrue();
+    assertThat(Keyword.isKeyword("for")).isTrue();
+
+    // Primitive types.
+    assertThat(Keyword.isKeyword("int")).isTrue();
+    assertThat(Keyword.isKeyword("char")).isTrue();
+
+    // Literal values.
+    assertThat(Keyword.isKeyword("false")).isFalse();
+    assertThat(Keyword.isKeyword("null")).isFalse();
+    assertThat(Keyword.isKeyword("asdf")).isFalse();
+    assertThat(Keyword.isKeyword("12345")).isFalse();
+  }
+}