AnnotationScanner


1   /*******************************************************************************
2    * Copyright (c) 2005, 2007 BEA Systems, Inc. 
3    * All rights reserved. This program and the accompanying materials
4    * are made available under the terms of the Eclipse Public License v1.0
5    * which accompanies this distribution, and is available at
6    * http://www.eclipse.org/legal/epl-v10.html
7    *
8    * Contributors:
9    *    jgarms@bea.com - initial API and implementation
10   *    
11   *******************************************************************************/
12  package org.eclipse.jdt.apt.core.internal.util;
13  
14  import java.io.IOException  ;
15  
16  import static org.eclipse.jdt.apt.core.internal.util.AnnotationScanner.State.*;
17  
18  /**
19   * Utility scanner for quickly determining if a file contains annotations
20   */
21  public abstract class AnnotationScanner {
22  
23      enum State {
24          NORMAL,
25          SEEN_SLASH,
26          IN_COMMENT,
27          IN_COMMENT_SEEN_STAR,
28          IN_SINGLE_LINE_COMMENT,
29          IN_SINGLE_QUOTE,
30          IN_DOUBLE_QUOTE
31      }
32      
33      public AnnotationScanner() {}
34      
35      public boolean containsAnnotations() throws IOException   {
36          State state = NORMAL;
37          
38          // for escaping quotes -- need to ignore the next single character
39          // Since this applies to all states it's handled separately
40          boolean seenBackslash = false;
41          
42          int c = getNext();
43          while (c != -1) {
44              
45              if (seenBackslash) {
46                  // Skip one character
47                  seenBackslash = false;
48              }
49              else if (c == '\\') {
50                  // Skip the next character
51                  seenBackslash = true;
52              }
53              else {
54                  // Handle the character based on state
55                  switch (state) {
56                  
57                  case NORMAL :
58                      if (c == '@')
59                          return true;
60                      if (c == '/') {
61                          state = SEEN_SLASH;
62                      }
63                      else if (c == '\'') {
64                          state = IN_SINGLE_QUOTE;
65                      }
66                      else if (c == '\"') {
67                          state = IN_DOUBLE_QUOTE;
68                      }
69                      break;
70                      
71                  case SEEN_SLASH :
72                      if (c == '*') {
73                          state = IN_COMMENT;
74                      }
75                      else if (c == '/') {
76                          state = IN_SINGLE_LINE_COMMENT;
77                      }
78                      else {
79                          state = NORMAL;
80                      }
81                      break;
82                  
83                  case IN_COMMENT :
84                      if (c == '*') {
85                          state = IN_COMMENT_SEEN_STAR;
86                      }
87                      break;
88                  
89                  case IN_COMMENT_SEEN_STAR :
90                      if (c == '/') {
91                          state = NORMAL;
92                      }
93                      else {
94                          state = IN_COMMENT;
95                      }
96                      break;
97                      
98                  case IN_SINGLE_LINE_COMMENT :
99                      if (c == '\n' || c == '\r') {
100                         state = NORMAL;
101                     }
102                     break;
103                     
104                 case IN_SINGLE_QUOTE :
105                     if (c == '\'') {
106                         state = NORMAL;
107                     }
108                     break;
109                     
110                 case IN_DOUBLE_QUOTE :
111                     if (c == '\"') {
112                         state = NORMAL;
113                     }
114                     break;
115                     
116                 default :
117                     throw new IllegalStateException  ("Unhandled state: " + state);  //$NON-NLS-1$
118                 }
119             }
120             c = getNext();
121         }
122         return false;
123     }
124     
125     /**
126      * Returns -1 at the end of the input
127      */
128     protected abstract int getNext() throws IOException  ;
129 }
130
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