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


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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 import edu.rice.cs.drjava.model.AbstractDJDocument;
39
40 /**
41  * Indents the current line in the document to the indent level of the
42  * start of the previous line, plus the given suffix, then backs up to a
43  * specific cursor position.
44  * @version $Id: ActionStartPrevLinePlusBackup.java 3901 2006-06-30 05:28:11Z rcartwright $
45  */
46 class ActionStartPrevLinePlusBackup extends IndentRuleAction {
47   private String JavaDoc _suffix;
48   private int _position = 0;
49
50   /**
51    * Rule that repeats the indentation from the previous line, plus a string,
52    * then moves the cursor to a specified location.
53    * @param suffix The string to be added
54    * @param position the character within the suffix string before which to
55    * place the cursor
56    * @throws IllegalArgumentException if the position is negative or
57    * outside the bounds of the suffix string
58    */
59   public ActionStartPrevLinePlusBackup(String JavaDoc suffix, int position) {
60     _suffix = suffix;
61     
62     if ((position >= 0) && (position <= suffix.length())) {
63       _position = position;
64     }
65     else {
66       throw new IllegalArgumentException JavaDoc
67         ("The specified position was not within the bounds of the suffix.");
68     }
69   }
70
71   /**
72    * Indents the line according to the previous line, with the suffix string added,
73    * then backs up the cursor position a number of characters.
74    * If on the first line, indent is set to 0.
75    * @param doc AbstractDJDocument containing the line to be indented.
76    * @return this is always false, since we are updating the cursor location
77    */
78   public boolean indentLine(AbstractDJDocument doc, int reason) {
79     super.indentLine(doc, reason);
80     try {
81       // Find start of line
82 int here = doc.getCurrentLocation();
83       int startLine = doc.getLineStartPos(here);
84
85       if (startLine > AbstractDJDocument.DOCSTART) {
86         // Find prefix of previous line
87 int startPrevLine = doc.getLineStartPos(startLine - 1);
88         int firstChar = doc.getLineFirstCharPos(startPrevLine);
89         String JavaDoc prefix = doc.getText(startPrevLine, firstChar - startPrevLine);
90         
91         // indent and add the suffix
92 doc.setTab(prefix + _suffix, here);
93         
94         // move the cursor to the new position
95 doc.setCurrentLocation(startLine + prefix.length() + _position);
96       }
97       else {
98         // On first line
99 doc.setTab(_suffix, here);
100         
101         // move the cursor to the new position
102 doc.setCurrentLocation(here + _position);
103       }
104       
105       return false;
106     }
107     catch (BadLocationException e) {
108       // Shouldn't happen
109 throw new UnexpectedException(e);
110     }
111   }
112 }
113
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