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

 // 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.imports;

 import java.io.File;

 import java.net.URI;

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

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

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

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

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

 import org.apache.commons.beanutils.ConversionException;

 /**

  * Check that controls what packages can be imported in each package. Useful

  * for ensuring that application layering is not violated. Ideas on how the

  * check can be improved include support for:

  * <ul>

  * <li>Change the default policy that if a package being checked does not

  *     match any guards, then it is allowed. Currently defaults to disallowed.

  *

  * </ul>

  * @author Oliver Burn

  */

 public class ImportControlCheck extends Check

 {

     /** The root package controller. */

     private PkgControl mRoot;

     /** The package doing the import. */

     private String mInPkg;

     /**

      * The package controller for the current file. Used for performance

      * optimisation.

      */

     private PkgControl mCurrentLeaf;

     @Override

     public int[] getDefaultTokens()

     {

         return new int[] {TokenTypes.PACKAGE_DEF, TokenTypes.IMPORT,

                           TokenTypes.STATIC_IMPORT, };

     }

     @Override

     public void beginTree(final DetailAST aRootAST)

     {

         mCurrentLeaf = null;

     }

     @Override

     public void visitToken(final DetailAST aAST)

     {

         if (aAST.getType() == TokenTypes.PACKAGE_DEF) {

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

             final FullIdent full = FullIdent.createFullIdent(nameAST);

             if (mRoot == null) {

                 log(nameAST, "import.control.missing.file");

             }

             else {

                 mInPkg = full.getText();

                 mCurrentLeaf = mRoot.locateFinest(mInPkg);

                 if (mCurrentLeaf == null) {

                     log(nameAST, "import.control.unknown.pkg");

                 }

             }

         }

         else if (mCurrentLeaf != null) {

             final FullIdent imp;

             if (aAST.getType() == TokenTypes.IMPORT) {

                 imp = FullIdent.createFullIdentBelow(aAST);

             }

             else {

                 // know it is a static import

                 imp = FullIdent.createFullIdent(aAST

                         .getFirstChild().getNextSibling());

             }

             final AccessResult access = mCurrentLeaf.checkAccess(imp.getText(),

                     mInPkg);

             if (!AccessResult.ALLOWED.equals(access)) {

                 log(aAST, "import.control.disallowed", imp.getText());

             }

         }

     }

     /**

      * Set the parameter for the url containing the import control

      * configuration. It will cause the url to be loaded.

      * @param aUrl the url of the file to load.

      * @throws ConversionException on error loading the file.

      */

     public void setUrl(final String aUrl)

     {

         // Handle empty param

         if ((aUrl == null) || (aUrl.trim().length() == 0)) {

             return;

         }

         final URI uri;

         try {

             uri = URI.create(aUrl);

         }

         catch (final IllegalArgumentException ex) {

             throw new ConversionException("syntax error in url " + aUrl, ex);

         }

         try {

             mRoot = ImportControlLoader.load(uri);

         }

         catch (final CheckstyleException ex) {

             throw new ConversionException("Unable to load " + aUrl, ex);

         }

     }

     /**

      * Set the parameter for the file containing the import control

      * configuration. It will cause the file to be loaded.

      * @param aName the name of the file to load.

      * @throws ConversionException on error loading the file.

      */

     public void setFile(final String aName)

     {

         // Handle empty param

         if ((aName == null) || (aName.trim().length() == 0)) {

             return;

         }

         try {

             mRoot = ImportControlLoader.load(new File(aName).toURI());

         }

         catch (final CheckstyleException ex) {

             throw new ConversionException("Unable to load " + aName, ex);

         }

     }

 }