Coverage Report - com.puppycrawl.tools.checkstyle.checks.design.InterfaceIsTypeCheck
 
Classes in this File Line Coverage Branch Coverage Complexity
InterfaceIsTypeCheck
100%
17/17
100%
8/8
1.6
 
 1  
 ////////////////////////////////////////////////////////////////////////////////
 2  
 // checkstyle: Checks Java source code for adherence to a set of rules.
 3  
 // Copyright (C) 2001-2017 the original author or authors.
 4  
 //
 5  
 // This library is free software; you can redistribute it and/or
 6  
 // modify it under the terms of the GNU Lesser General Public
 7  
 // License as published by the Free Software Foundation; either
 8  
 // version 2.1 of the License, or (at your option) any later version.
 9  
 //
 10  
 // This library is distributed in the hope that it will be useful,
 11  
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 12  
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 13  
 // Lesser General Public License for more details.
 14  
 //
 15  
 // You should have received a copy of the GNU Lesser General Public
 16  
 // License along with this library; if not, write to the Free Software
 17  
 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 18  
 ////////////////////////////////////////////////////////////////////////////////
 19  
 
 20  
 package com.puppycrawl.tools.checkstyle.checks.design;
 21  
 
 22  
 import com.puppycrawl.tools.checkstyle.StatelessCheck;
 23  
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 24  
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
 25  
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 26  
 
 27  
 /**
 28  
  * Implements Bloch, Effective Java, Item 17 -
 29  
  * Use Interfaces only to define types.
 30  
  *
 31  
  * <p>
 32  
  * An interface should describe a <em>type</em>, it is therefore
 33  
  * inappropriate to define an interface that does not contain any methods
 34  
  * but only constants.
 35  
  * </p>
 36  
  *
 37  
  * <p>
 38  
  * The check can be configured to also disallow marker interfaces like
 39  
  * {@code java.io.Serializable}, that do not contain methods or
 40  
  * constants at all.
 41  
  * </p>
 42  
  *
 43  
  * @author lkuehne
 44  
  */
 45  
 @StatelessCheck
 46  11
 public final class InterfaceIsTypeCheck
 47  
         extends AbstractCheck {
 48  
 
 49  
     /**
 50  
      * A key is pointing to the warning message text in "messages.properties"
 51  
      * file.
 52  
      */
 53  
     public static final String MSG_KEY = "interface.type";
 54  
 
 55  
     /** Flag to control whether marker interfaces are allowed. */
 56  11
     private boolean allowMarkerInterfaces = true;
 57  
 
 58  
     @Override
 59  
     public int[] getDefaultTokens() {
 60  25
         return new int[] {TokenTypes.INTERFACE_DEF};
 61  
     }
 62  
 
 63  
     @Override
 64  
     public int[] getRequiredTokens() {
 65  13
         return getDefaultTokens();
 66  
     }
 67  
 
 68  
     @Override
 69  
     public int[] getAcceptableTokens() {
 70  5
         return new int[] {TokenTypes.INTERFACE_DEF};
 71  
     }
 72  
 
 73  
     @Override
 74  
     public void visitToken(DetailAST ast) {
 75  6
         final DetailAST objBlock =
 76  6
                 ast.findFirstToken(TokenTypes.OBJBLOCK);
 77  6
         final DetailAST methodDef =
 78  6
                 objBlock.findFirstToken(TokenTypes.METHOD_DEF);
 79  6
         final DetailAST variableDef =
 80  6
                 objBlock.findFirstToken(TokenTypes.VARIABLE_DEF);
 81  6
         final boolean methodRequired =
 82  
                 !allowMarkerInterfaces || variableDef != null;
 83  
 
 84  6
         if (methodDef == null && methodRequired) {
 85  3
             log(ast.getLineNo(), MSG_KEY);
 86  
         }
 87  
 
 88  6
     }
 89  
 
 90  
     /**
 91  
      * Controls whether marker interfaces like Serializable are allowed.
 92  
      * @param flag whether to allow marker interfaces or not
 93  
      */
 94  
     public void setAllowMarkerInterfaces(boolean flag) {
 95  1
         allowMarkerInterfaces = flag;
 96  1
     }
 97  
 }