Java 类com.intellij.psi.tree.java.IKeywordElementType 实例源码

/**
 * Validates a potential package name and returns null if the package name is valid, and otherwise
 * returns a description for why it is not valid.
 * <p>
 * Note that Android package names are more restrictive than general Java package names;
 * we require at least two segments, limit the character set to [a-zA-Z0-9_] (Java allows any
 * {@link Character#isLetter(char)} and require that each segment start with a letter (Java allows
 * underscores at the beginning).
 * <p>
 * For details, see core/java/android/content/pm/PackageParser.java#validateName
 *
 * @param name the package name
 * @return null if the package is valid as an Android package name, and otherwise a description for why not
 */
@Nullable
public static String validateAndroidPackageName(@NotNull String name) {
  if (name.isEmpty()) {
    return "Package name is missing";
  }

  String packageManagerCheck = validateName(name, true);
  if (packageManagerCheck != null) {
    return packageManagerCheck;
  }

  // In addition, we have to check that none of the segments are Java identifiers, since
  // that will lead to compilation errors, which the package manager doesn't need to worry about
  // (the code wouldn't have compiled)

  ApplicationManager.getApplication().assertReadAccessAllowed();
  Lexer lexer = JavaParserDefinition.createLexer(LanguageLevel.JDK_1_5);
  int index = 0;
  while (true) {
    int index1 = name.indexOf('.', index);
    if (index1 < 0) {
      index1 = name.length();
    }
    String segment = name.substring(index, index1);
    lexer.start(segment);
    if (lexer.getTokenType() != JavaTokenType.IDENTIFIER) {
      if (lexer.getTokenType() instanceof IKeywordElementType) {
        return "Package names cannot contain Java keywords like '" + segment + "'";
      }
      if (segment.isEmpty()) {
        return "Package segments must be of non-zero length";
      }
      return segment + " is not a valid identifier";
    }
    if (index1 == name.length()) {
      break;
    }
    index = index1 + 1;
  }

  return null;
}