////////////////////////////////////////////////////////////////////////////////

 // checkstyle: Checks Java source code for adherence to a set of rules.

 // Copyright (C) 2001-2014  Oliver Burn

 //

 // This library is free software; you can redistribute it and/or

 // modify it under the terms of the GNU Lesser General Public

 // License as published by the Free Software Foundation; either

 // version 2.1 of the License, or (at your option) any later version.

 //

 // This library is distributed in the hope that it will be useful,

 // but WITHOUT ANY WARRANTY; without even the implied warranty of

 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 // Lesser General Public License for more details.

 //

 // You should have received a copy of the GNU Lesser General Public

 // License along with this library; if not, write to the Free Software

 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 ////////////////////////////////////////////////////////////////////////////////

 package com.puppycrawl.tools.checkstyle.checks.naming;

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

 import com.puppycrawl.tools.checkstyle.api.FullIdent;

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

 import com.puppycrawl.tools.checkstyle.checks.AbstractFormatCheck;

 /**

  * <p>

  * Checks that package names conform to a format specified

  * by the format property. The format is a

  * {@link java.util.regex.Pattern regular expression}

  * and defaults to

  * <strong>^[a-z]+(\.[a-zA-Z_][a-zA-Z_0-9]*)*$</strong>.

  * </p>

  * <p>

  * The default format has been chosen to match the requirements in the

  * <a

  * href="http://java.sun.com/docs/books/jls/second_edition/html/packages.doc.html#40169">

  * Java Language specification</a> and the Sun coding conventions.

  * However both underscores and uppercase letters are rather uncommon,

  * so most projects should probably use

  * <strong>^[a-z]+(\.[a-z][a-z0-9]*)*$</strong>.

  * </p>

  * <p>

  * An example of how to configure the check is:

  * </p>

  * <pre>

  * <module name="PackageName"/>

  * </pre>

  * <p>

  * An example of how to configure the check for package names that begin with

  * <code>com.puppycrawl.tools.checkstyle</code> is:

  * </p>

  * <pre>

  * <module name="PackageName">

  *    <property name="format"

  *              value="^com\.puppycrawl\.tools\.checkstyle(\\.[a-zA-Z_][a-zA-Z_0-9]*)*$"/>

  * </module>

  * </pre>

  *

  * @author Oliver Burn

  * @version 1.0

  */

 public class PackageNameCheck

     extends AbstractFormatCheck

 {

     /**

      * Creates a new <code>PackageNameCheck</code> instance.

      */

     public PackageNameCheck()

     {

         // Uppercase letters seem rather uncommon, but they're allowed in

         // http://java.sun.com/docs/books/jls/

         //   second_edition/html/packages.doc.html#40169

         super("^[a-z]+(\\.[a-zA-Z_][a-zA-Z0-9_]*)*$");

     }

     @Override

     public int[] getDefaultTokens()

     {

         return new int[] {TokenTypes.PACKAGE_DEF};

     }

     @Override

     public void visitToken(DetailAST aAST)

     {

         final DetailAST nameAST = aAST.getLastChild().getPreviousSibling();

         final FullIdent full = FullIdent.createFullIdent(nameAST);

         if (!getRegexp().matcher(full.getText()).find()) {

             log(full.getLineNo(),

                 full.getColumnNo(),

                 "name.invalidPattern",

                 full.getText(),

                 getFormat());

         }

     }

 }