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Java > Open Source Codes > edu > rice > cs > drjava > model > definitions > indent > QuestionCurrLineStartsWithSkipComments


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33
34 package edu.rice.cs.drjava.model.definitions.indent;
35
36 import javax.swing.text.*;
37 import edu.rice.cs.util.UnexpectedException;
38
39 import edu.rice.cs.drjava.model.AbstractDJDocument;
40 import edu.rice.cs.drjava.model.definitions.reducedmodel.*;
41
42 /** Determines whether or not the current line in the document starts with a specific character sequence,
43  * skipping over any comments on that line. The character sequence is passed to the constructor of the class
44  * as a String argument.
45  * @version $Id: QuestionCurrLineStartsWithSkipComments.java 3900 2006-06-29 13:16:38Z rcartwright $
46  */
47 public class QuestionCurrLineStartsWithSkipComments extends IndentRuleQuestion {
48   /** The String to be matched. This String may not contain whitespace characters
49    * or comment-delimiting characters.
50    */
51   private String JavaDoc _prefix;
52   
53   /** @param yesRule The decision subtree for the case that this rule applies in the current context.
54    * @param noRule The decision subtree for the case that this rule does not apply in the current context.
55    */
56   public QuestionCurrLineStartsWithSkipComments(String JavaDoc prefix, IndentRule yesRule, IndentRule noRule) {
57     super(yesRule, noRule);
58     _prefix = prefix;
59   }
60   
61   /** Determines whether or not the current line in the document starts
62    * with the character sequence specified by the String field _prefix,
63    * skipping over any comments on that line.
64    * @param doc The AbstractDJDocument containing the current line.
65    * @return True iff the current line in the document starts with the
66    * character sequence specified by the String field _prefix.
67    */
68   boolean applyRule(AbstractDJDocument doc, int reason) {
69     try {
70       // Find the first non-whitespace character on the current line.
71
72       int currentPos = doc.getCurrentLocation(),
73         startPos = doc.getLineFirstCharPos(currentPos),
74         endPos = doc.getLineEndPos(currentPos),
75         lineLength = endPos - startPos;
76       
77       char currentChar, previousChar = '\0';
78       String JavaDoc text = doc.getText(startPos, lineLength);
79       
80       for (int i = 0; i < lineLength; i++) {
81         // Get state for walker position.
82 //BraceReduction reduced = doc.getReduced();
83
84         doc.move( startPos - currentPos + i);
85         ReducedModelState state = doc.getStateAtCurrent();
86         doc.move(-startPos + currentPos - i);
87         
88         
89         currentChar = text.charAt(i);
90         
91         if (state.equals(ReducedModelState.INSIDE_LINE_COMMENT)) return false;
92         if (state.equals(ReducedModelState.INSIDE_BLOCK_COMMENT)) { // Handle case: ...*/*
93 previousChar = '\0';
94           continue;
95         }
96         if (state.equals(ReducedModelState.FREE)) { // Can prefix still fit on the current line?
97 if (_prefix.length() > lineLength - i) return false;
98           else if (text.substring(i, i+_prefix.length()).equals(_prefix) && previousChar != '/') {
99             // '/' is the only non-WS character that we consume without
100 // immediately returning false. When we try to match the prefix,
101 // we also need to reflect this implicit lookahead mechanism.
102 return true;
103           }
104           else if (currentChar == '/') {
105             if (previousChar == '/') return false;
106           }
107           else if (currentChar == ' ' || currentChar == '\t') { }
108           else if (!(currentChar == '*' && previousChar == '/')) return false;
109         }
110         if (previousChar == '/' && currentChar != '*') return false;
111         previousChar = currentChar;
112       }
113       return false;
114     }
115     catch (BadLocationException e) {
116       // Control flow should never reach this point!
117 throw new UnexpectedException(new RuntimeException JavaDoc("Bug in QuestionCurrLineStartsWithSkipComments"));
118     }
119   }
120 }
121
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