ParseException


1   /* Generated By:JavaCC: Do not edit this line. ParseException.java Version 3.0 */
2   package org.nfunk.jep;
3   
4   /**
5    * This exception is thrown when parse errors are encountered.
6    * You can explicitly create objects of this exception type by
7    * calling the method generateParseException in the generated
8    * parser.
9    *
10   * You can modify this class to customize your error reporting
11   * mechanisms so long as you retain the public fields.
12   */
13  public class ParseException extends Exception   {
14  
15    /**
16     * This constructor is used by the method "generateParseException"
17     * in the generated parser.  Calling this constructor generates
18     * a new object of this type with the fields "currentToken",
19     * "expectedTokenSequences", and "tokenImage" set.  The boolean
20     * flag "specialConstructor" is also set to true to indicate that
21     * this constructor was used to create this object.
22     * This constructor calls its super class with the empty string
23     * to force the "toString" method of parent class "Throwable" to
24     * print the error message in the form:
25     *     ParseException: <result of getMessage>
26     */
27    public ParseException(Token currentTokenVal,
28                          int[][] expectedTokenSequencesVal,
29                          String  [] tokenImageVal
30                         )
31    {
32      super("");
33      specialConstructor = true;
34      currentToken = currentTokenVal;
35      expectedTokenSequences = expectedTokenSequencesVal;
36      tokenImage = tokenImageVal;
37    }
38  
39    /**
40     * The following constructors are for use by you for whatever
41     * purpose you can think of.  Constructing the exception in this
42     * manner makes the exception behave in the normal way - i.e., as
43     * documented in the class "Throwable".  The fields "errorToken",
44     * "expectedTokenSequences", and "tokenImage" do not contain
45     * relevant information.  The JavaCC generated code does not use
46     * these constructors.
47     */
48  
49    public ParseException() {
50      super();
51      specialConstructor = false;
52    }
53  
54    public ParseException(String   message) {
55      super(message);
56      specialConstructor = false;
57    }
58  
59    /**
60     * This variable determines which constructor was used to create
61     * this object and thereby affects the semantics of the
62     * "getMessage" method (see below).
63     */
64    protected boolean specialConstructor;
65  
66    /**
67     * This is the last token that has been consumed successfully.  If
68     * this object has been created due to a parse error, the token
69     * followng this token will (therefore) be the first error token.
70     */
71    public Token currentToken;
72  
73    /**
74     * Each entry in this array is an array of integers.  Each array
75     * of integers represents a sequence of tokens (by their ordinal
76     * values) that is expected at this point of the parse.
77     */
78    public int[][] expectedTokenSequences;
79  
80    /**
81     * This is a reference to the "tokenImage" array of the generated
82     * parser within which the parse error occurred.  This array is
83     * defined in the generated ...Constants interface.
84     */
85    public String  [] tokenImage;
86  
87    /**
88     * This method has the standard behavior when this object has been
89     * created using the standard constructors.  Otherwise, it uses
90     * "currentToken" and "expectedTokenSequences" to generate a parse
91     * error message and returns it.  If this object has been created
92     * due to a parse error, and you do not catch it (it gets thrown
93     * from the parser), then this method is called during the printing
94     * of the final stack trace, and hence the correct error message
95     * gets displayed.
96     */
97    public String   getMessage() {
98      if (!specialConstructor) {
99        return super.getMessage();
100     }
101     String   expected = "";
102     int maxSize = 0;
103     for (int i = 0; i < expectedTokenSequences.length; i++) {
104       if (maxSize < expectedTokenSequences[i].length) {
105         maxSize = expectedTokenSequences[i].length;
106       }
107       for (int j = 0; j < expectedTokenSequences[i].length; j++) {
108         expected += tokenImage[expectedTokenSequences[i][j]] + " ";
109       }
110       if (expectedTokenSequences[i][expectedTokenSequences[i].length - 1] != 0) {
111         expected += "...";
112       }
113       expected += eol + "    ";
114     }
115     String   retval = "Encountered \"";
116     Token tok = currentToken.next;
117     for (int i = 0; i < maxSize; i++) {
118       if (i != 0) retval += " ";
119       if (tok.kind == 0) {
120         retval += tokenImage[0];
121         break;
122       }
123       retval += add_escapes(tok.image);
124       tok = tok.next; 
125     }
126     retval += "\" at line " + currentToken.next.beginLine + ", column " + currentToken.next.beginColumn;
127     retval += "." + eol;
128     if (expectedTokenSequences.length == 1) {
129       retval += "Was expecting:" + eol + "    ";
130     } else {
131       retval += "Was expecting one of:" + eol + "    ";
132     }
133     retval += expected;
134     return retval;
135   }
136   
137   /**
138    * getErrorInfo() was added to the parser generated code to provide clean
139    * output instead of the standard format of Exception.toString(). It returns
140    * a short description of the error that occured as well as the position of
141    * next token as part of the string.
142    */
143   public String   getErrorInfo()
144   {
145     if (!specialConstructor) {
146       try {
147         return super.getMessage() + " at column " + currentToken.next.beginColumn + ".";
148       }
149       catch (Exception   e) {
150         return super.getMessage();
151       }
152     }
153     String   expected = "";
154     int maxSize = 0;
155     for (int i = 0; i < expectedTokenSequences.length; i++) {
156       if (maxSize < expectedTokenSequences[i].length) {
157         maxSize = expectedTokenSequences[i].length;
158       }
159       for (int j = 0; j < expectedTokenSequences[i].length; j++) {
160         expected += tokenImage[expectedTokenSequences[i][j]] + " ";
161       }
162       if (expectedTokenSequences[i][expectedTokenSequences[i].length - 1] != 0) {
163         expected += "...";
164       }
165       expected += eol + "    ";
166     }
167 
168     String   retval = "Unexpected \"";
169     Token tok = currentToken.next;
170     for (int i = 0; i < maxSize; i++) {
171       if (i != 0) retval += " ";
172       if (tok.kind == 0) {
173         retval += tokenImage[0];
174         break;
175       }
176       retval += add_escapes(tok.image);
177       tok = tok.next;
178     }
179     retval += "\" at column " + currentToken.next.beginColumn + ".";
180     return retval;
181   }
182 
183   /**
184    * The end of line string for this machine.
185    */
186   protected String   eol = System.getProperty("line.separator", "\n");
187  
188   /**
189    * Used to convert raw characters to their escaped version
190    * when these raw version cannot be used as part of an ASCII
191    * string literal.
192    */
193   protected String   add_escapes(String   str) {
194       StringBuffer   retval = new StringBuffer  ();
195       char ch;
196       for (int i = 0; i < str.length(); i++) {
197         switch (str.charAt(i))
198         {
199            case 0 :
200               continue;
201            case '\b':
202               retval.append("\\b");
203               continue;
204            case '\t':
205               retval.append("\\t");
206               continue;
207            case '\n':
208               retval.append("\\n");
209               continue;
210            case '\f':
211               retval.append("\\f");
212               continue;
213            case '\r':
214               retval.append("\\r");
215               continue;
216            case '\"':
217               retval.append("\\\"");
218               continue;
219            case '\'':
220               retval.append("\\\'");
221               continue;
222            case '\\':
223               retval.append("\\\\");
224               continue;
225            default:
226               if ((ch = str.charAt(i)) < 0x20 || ch > 0x7e) {
227                  String   s = "0000" + Integer.toString(ch, 16);
228                  retval.append("\\u" + s.substring(s.length() - 4, s.length()));
229               } else {
230                  retval.append(ch);
231               }
232               continue;
233         }
234       }
235       return retval.toString();
236    }
237 
238 }
239
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