////////////////////////////////////////////////////////////////////////////////
   // checkstyle: Checks Java source code for adherence to a set of rules.
   // Copyright (C) 2001-2019 the original author or authors.
   //
   // 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.util.ArrayList;
  import java.util.List;
  
  import com.puppycrawl.tools.checkstyle.StatelessCheck;
  import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
  import com.puppycrawl.tools.checkstyle.api.DetailAST;
  import com.puppycrawl.tools.checkstyle.api.FullIdent;
  import com.puppycrawl.tools.checkstyle.api.TokenTypes;
  
  /**
   * <p>
   * Check that finds import statements that use the * notation.
   * </p>
   * <p>
   * Rationale: Importing all classes from a package or static
   * members from a class leads to tight coupling between packages
   * or classes and might lead to problems when a new version of a
   * library introduces name clashes.
   * </p>
   * <p>
   * An example of how to configure the check is:
   * </p>
   * <pre>
   * &lt;module name="AvoidStarImport"&gt;
   *   &lt;property name="excludes" value="java.io,java.net,java.lang.Math"/&gt;
   *   &lt;property name="allowClassImports" value="false"/&gt;
   *   &lt;property name="allowStaticMemberImports" value="false"/&gt;
   * &lt;/module&gt;
   * </pre>
   * The optional "excludes" property allows for certain packages like
   * java.io or java.net to be exempted from the rule. It also is used to
   * allow certain classes like java.lang.Math or java.io.File to be
   * excluded in order to support static member imports.
   *
   * <p>The optional "allowClassImports" when set to true, will allow starred
   * class imports but will not affect static member imports.
   *
   * <p>The optional "allowStaticMemberImports" when set to true will allow
   * starred static member imports but will not affect class imports.
   *
   */
  @StatelessCheck
  public class AvoidStarImportCheck
      extends AbstractCheck {
  
      /**
       * A key is pointing to the warning message text in "messages.properties"
       * file.
       */
      public static final String MSG_KEY = "import.avoidStar";
  
      /** Suffix for the star import. */
      private static final String STAR_IMPORT_SUFFIX = ".*";
  
      /** The packages/classes to exempt from this check. */
      private final List<String> excludes = new ArrayList<>();
  
      /** Whether to allow all class imports. */
      private boolean allowClassImports;
  
      /** Whether to allow all static member imports. */
      private boolean allowStaticMemberImports;
  
      @Override
      public int[] getDefaultTokens() {
          return getRequiredTokens();
      }
  
      @Override
      public int[] getAcceptableTokens() {
          return getRequiredTokens();
      }
  
      @Override
      public int[] getRequiredTokens() {
          // original implementation checks both IMPORT and STATIC_IMPORT tokens to avoid ".*" imports
          // however user can allow using "import" or "import static"
          // by configuring allowClassImports and allowStaticMemberImports
         // To avoid potential confusion when user specifies conflicting options on configuration
         // (see example below) we are adding both tokens to Required list
         //   <module name="AvoidStarImport">
         //      <property name="tokens" value="IMPORT"/>
         //      <property name="allowStaticMemberImports" value="false"/>
         //   </module>
         return new int[] {TokenTypes.IMPORT, TokenTypes.STATIC_IMPORT};
     }
 
     /**
      * Sets the list of packages or classes to be exempt from the check.
      * The excludes can contain a .* or not.
      * @param excludesParam a list of package names/fully-qualifies class names
      *     where star imports are ok.
      */
     public void setExcludes(String... excludesParam) {
         for (final String exclude : excludesParam) {
             if (exclude.endsWith(STAR_IMPORT_SUFFIX)) {
                 excludes.add(exclude);
             }
             else {
                 excludes.add(exclude + STAR_IMPORT_SUFFIX);
             }
         }
     }
 
     /**
      * Sets whether or not to allow all non-static class imports.
      * @param allow true to allow false to disallow
      */
     public void setAllowClassImports(boolean allow) {
         allowClassImports = allow;
     }
 
     /**
      * Sets whether or not to allow all static member imports.
      * @param allow true to allow false to disallow
      */
     public void setAllowStaticMemberImports(boolean allow) {
         allowStaticMemberImports = allow;
     }
 
     @Override
     public void visitToken(final DetailAST ast) {
         if (!allowClassImports && ast.getType() == TokenTypes.IMPORT) {
             final DetailAST startingDot = ast.getFirstChild();
             logsStarredImportViolation(startingDot);
         }
         else if (!allowStaticMemberImports
             && ast.getType() == TokenTypes.STATIC_IMPORT) {
             // must navigate past the static keyword
             final DetailAST startingDot = ast.getFirstChild().getNextSibling();
             logsStarredImportViolation(startingDot);
         }
     }
 
     /**
      * Gets the full import identifier.  If the import is a starred import and
      * it's not excluded then a violation is logged.
      * @param startingDot the starting dot for the import statement
      */
     private void logsStarredImportViolation(DetailAST startingDot) {
         final FullIdent name = FullIdent.createFullIdent(startingDot);
         final String importText = name.getText();
         if (importText.endsWith(STAR_IMPORT_SUFFIX) && !excludes.contains(importText)) {
             log(startingDot.getLineNo(), MSG_KEY, importText);
         }
     }
 
 }