Coverage Report - com.puppycrawl.tools.checkstyle.checks.blocks.AvoidNestedBlocksCheck
 
Classes in this File Line Coverage Branch Coverage Complexity
AvoidNestedBlocksCheck
100%
12/12
100%
8/8
1.8
 
 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.blocks;
 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  
  * Finds nested blocks.
 29  
  *
 30  
  * <p>
 31  
  * For example this Check flags confusing code like
 32  
  * </p>
 33  
  * <pre>
 34  
  * public void guessTheOutput()
 35  
  * {
 36  
  *     int whichIsWhich = 0;
 37  
  *     {
 38  
  *         int whichIsWhich = 2;
 39  
  *     }
 40  
  *     System.out.println("value = " + whichIsWhich);
 41  
  * }
 42  
  * </pre>
 43  
  * and debugging / refactoring leftovers such as
 44  
  *
 45  
  * <pre>
 46  
  * // if (someOldCondition)
 47  
  * {
 48  
  *     System.out.println("unconditional");
 49  
  * }
 50  
  * </pre>
 51  
  *
 52  
  * <p>
 53  
  * A case in a switch statement does not implicitly form a block.
 54  
  * Thus to be able to introduce local variables that have case scope
 55  
  * it is necessary to open a nested block. This is supported, set
 56  
  * the allowInSwitchCase property to true and include all statements
 57  
  * of the case in the block.
 58  
  * </p>
 59  
  *
 60  
  * <pre>
 61  
  * switch (a)
 62  
  * {
 63  
  *     case 0:
 64  
  *         // Never OK, break outside block
 65  
  *         {
 66  
  *             x = 1;
 67  
  *         }
 68  
  *         break;
 69  
  *     case 1:
 70  
  *         // Never OK, statement outside block
 71  
  *         System.out.println("Hello");
 72  
  *         {
 73  
  *             x = 2;
 74  
  *             break;
 75  
  *         }
 76  
  *     case 1:
 77  
  *         // OK if allowInSwitchCase is true
 78  
  *         {
 79  
  *             System.out.println("Hello");
 80  
  *             x = 2;
 81  
  *             break;
 82  
  *         }
 83  
  * }
 84  
  * </pre>
 85  
  *
 86  
  * @author lkuehne
 87  
  */
 88  
 @StatelessCheck
 89  11
 public class AvoidNestedBlocksCheck extends AbstractCheck {
 90  
     /**
 91  
      * A key is pointing to the warning message text in "messages.properties"
 92  
      * file.
 93  
      */
 94  
     public static final String MSG_KEY_BLOCK_NESTED = "block.nested";
 95  
 
 96  
     /**
 97  
      * Whether nested blocks are allowed if they are the
 98  
      * only child of a switch case.
 99  
      */
 100  
     private boolean allowInSwitchCase;
 101  
 
 102  
     @Override
 103  
     public int[] getDefaultTokens() {
 104  12
         return getRequiredTokens();
 105  
     }
 106  
 
 107  
     @Override
 108  
     public int[] getAcceptableTokens() {
 109  5
         return getRequiredTokens();
 110  
     }
 111  
 
 112  
     @Override
 113  
     public int[] getRequiredTokens() {
 114  30
         return new int[] {TokenTypes.SLIST};
 115  
     }
 116  
 
 117  
     @Override
 118  
     public void visitToken(DetailAST ast) {
 119  22
         final DetailAST parent = ast.getParent();
 120  22
         if (parent.getType() == TokenTypes.SLIST
 121  
                 && (!allowInSwitchCase
 122  4
                     || parent.getParent().getType() != TokenTypes.CASE_GROUP
 123  3
                     || parent.getNumberOfChildren() != 1)) {
 124  7
             log(ast.getLineNo(), ast.getColumnNo(), MSG_KEY_BLOCK_NESTED);
 125  
         }
 126  22
     }
 127  
 
 128  
     /**
 129  
      * Setter for allowInSwitchCase property.
 130  
      * @param allowInSwitchCase whether nested blocks are allowed
 131  
      *                 if they are the only child of a switch case.
 132  
      */
 133  
     public void setAllowInSwitchCase(boolean allowInSwitchCase) {
 134  1
         this.allowInSwitchCase = allowInSwitchCase;
 135  1
     }
 136  
 }