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Java > Open Source Codes > com > puppycrawl > tools > checkstyle > checks > indentation > IfHandler


1 ////////////////////////////////////////////////////////////////////////////////
2 // checkstyle: Checks Java source code for adherence to a set of rules.
3 // Copyright (C) 2001-2005 Oliver Burn
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 package com.puppycrawl.tools.checkstyle.checks.indentation;
20
21 import com.puppycrawl.tools.checkstyle.api.DetailAST;
22 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
23
24 /**
25  * Handler for if statements.
26  *
27  * @author jrichard
28  */
29 public class IfHandler extends BlockParentHandler
30 {
31     /**
32      * Construct an instance of this handler with the given indentation check,
33      * abstract syntax tree, and parent handler.
34      *
35      * @param aIndentCheck the indentation check
36      * @param aAst the abstract syntax tree
37      * @param aParent the parent handler
38      */
39     public IfHandler(IndentationCheck aIndentCheck,
40         DetailAST aAst, ExpressionHandler aParent)
41     {
42         super(aIndentCheck, "if", aAst, aParent);
43     }
44
45     /**
46      * Indentation level suggested for a child element. Children don't have
47      * to respect this, but most do.
48      *
49      * @param aChild child AST (so suggestion level can differ based on child
50      * type)
51      *
52      * @return suggested indentation for child
53      */
54     public IndentLevel suggestedChildLevel(ExpressionHandler aChild)
55     {
56         if (aChild instanceof ElseHandler) {
57             return getLevel();
58         }
59         return super.suggestedChildLevel(aChild);
60     }
61
62     /**
63      * Compute the indentation amount for this handler.
64      *
65      * @return the expected indentation amount
66      */
67     protected IndentLevel getLevelImpl()
68     {
69         if (isIfAfterElse()) {
70             return getParent().getLevel();
71         }
72         return super.getLevelImpl();
73     }
74
75     /**
76      * Determines if this 'if' statement is part of an 'else' clause
77      * and on the same line.
78      *
79      * @return true if this 'if' is part of an 'else', false otherwise
80      */
81     private boolean isIfAfterElse()
82     {
83         // check if there is an 'else' and an 'if' on the same line
84 final DetailAST parent = getMainAst().getParent();
85         return (parent.getType() == TokenTypes.LITERAL_ELSE)
86             && (parent.getLineNo() == getMainAst().getLineNo());
87     }
88
89     /**
90      * Check the indentation of the top level token.
91      */
92     protected void checkToplevelToken()
93     {
94         if (isIfAfterElse()) {
95             return;
96         }
97
98         super.checkToplevelToken();
99     }
100
101     /**
102      * Check the indentation of the conditional expression.
103      */
104     private void checkCondExpr()
105     {
106         final DetailAST condAst = (DetailAST)
107             getMainAst().findFirstToken(TokenTypes.LPAREN).getNextSibling();
108         final IndentLevel expected =
109             new IndentLevel(getLevel(), getBasicOffset());
110         checkExpressionSubtree(condAst, expected, false, false);
111     }
112
113     /**
114      * Check the indentation of the expression we are handling.
115      */
116     public void checkIndentation()
117     {
118         super.checkIndentation();
119         checkCondExpr();
120     }
121 }
122
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