CheckStyleUtils.java

// =================================================================================================
// Copyright 2011 Twitter, Inc.
// -------------------------------------------------------------------------------------------------
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this work except in compliance with the License.
// You may obtain a copy of the License in the LICENSE file, or 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.twitter.common.checkstyle;

import com.puppycrawl.tools.checkstyle.api.Check;
import com.puppycrawl.tools.checkstyle.api.DetailAST;
import com.puppycrawl.tools.checkstyle.api.TokenTypes;

/**
 * Utilities needed by custom checkstyle rules.
 *
 * @author Utkarsh Srivastava
 */
public final class CheckStyleUtils {

  private CheckStyleUtils() {
    // utility
  }

  /**
   * Returns the message bundle to use for a custom rule. All built-in rules in checkstyle have
   * a message bundle in the same package as that rule. This method returns the path to that
   * bundle.
   *
   * @param parentBuiltInCheckClass The class of the built-in checkstyle rule that the custom rule
   *     ultimately derives from.
   * @return Path to message bundle.
   */
  public static String getMessageBundle(final Class<? extends Check> parentBuiltInCheckClass) {
    String parentBuiltInCheckClassName = parentBuiltInCheckClass.getName();
    // This code is copied from com.puppycrawl.tools.checkstyle.api.
    // AbstractViolationReporter.java::getMessageBundle(String s)
    // If that method were protected (and not package private) we could
    // just invoke it
    final int endIndex = parentBuiltInCheckClassName.lastIndexOf('.');
    final String messages = "messages";
    if (endIndex < 0) {
      return messages;
    }
    final String packageName = parentBuiltInCheckClassName.substring(0, endIndex);
    return packageName + "." + messages;
  }

  /**
   * Checks to see if a method has the "@Override" annotation.
   *
   * @param aAST The AST to check.
   * @return Whether the AST represents a method that has the annotation.
   */
  public static boolean isOverrideMethod(DetailAST aAST) {
    // Need it to be a method, cannot have an override on anything else.
    // Must also have MODIFIERS token to hold the @Override
    if ((TokenTypes.METHOD_DEF != aAST.getType())
        || (TokenTypes.MODIFIERS != aAST.getFirstChild().getType())) {
      return false;
    }

    // Now loop over all nodes while they are annotations looking for
    // an "@Override".
    DetailAST node = aAST.getFirstChild().getFirstChild();
    while ((null != node) && (TokenTypes.ANNOTATION == node.getType())) {
      if ((node.getFirstChild().getType() == TokenTypes.AT)
          && (node.getFirstChild().getNextSibling().getType() == TokenTypes.IDENT)
          && ("Override".equals(node.getFirstChild().getNextSibling().getText()))) {
          return true;
      }
      node = node.getNextSibling();
    }
    return false;
  }
}