PositionManager


1   /*
2    * PositionManager.java - Manages positions
3    * :tabSize=8:indentSize=8:noTabs=false:
4    * :folding=explicit:collapseFolds=1:
5    *
6    * Copyright (C) 2001, 2005 Slava Pestov
7    *
8    * This program is free software; you can redistribute it and/or
9    * modify it under the terms of the GNU General Public License
10   * as published by the Free Software Foundation; either version 2
11   * of the License, or any later version.
12   *
13   * This program is distributed in the hope that it will be useful,
14   * but WITHOUT ANY WARRANTY; without even the implied warranty of
15   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16   * GNU General Public License for more details.
17   *
18   * You should have received a copy of the GNU General Public License
19   * along with this program; if not, write to the Free Software
20   * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
21   */
22  
23  package org.gjt.sp.jedit.buffer;
24  
25  //{{{ Imports
26  import javax.swing.text.Position  ;
27  import java.util.*;
28  import org.gjt.sp.util.Log;
29  //}}}
30  
31  /**
32   * A class internal to jEdit's document model. You should not use it
33   * directly.
34   *
35   * @author Slava Pestov
36   * @version $Id: PositionManager.java 5339 2006-01-25 23:12:07Z spestov $
37   * @since jEdit 4.2pre3
38   */
39  public class PositionManager
40  {
41      //{{{ PositionManager constructor
42      public PositionManager(JEditBuffer buffer)
43      {
44          this.buffer = buffer;
45      } //}}}
46      
47      //{{{ createPosition() method
48      public synchronized Position   createPosition(int offset)
49      {
50          PosBottomHalf bh = new PosBottomHalf(offset);
51          PosBottomHalf existing = (PosBottomHalf)positions.get(bh);
52          if(existing == null)
53          {
54              positions.put(bh,bh);
55              existing = bh;
56          }
57  
58          return new PosTopHalf(existing);
59      } //}}}
60  
61      //{{{ contentInserted() method
62      public synchronized void contentInserted(int offset, int length)
63      {
64          if(positions.size() == 0)
65              return;
66  
67          /* get all positions from offset to the end, inclusive */
68          Iterator iter = positions.tailMap(new PosBottomHalf(offset))
69              .keySet().iterator();
70  
71          iteration = true;
72          while(iter.hasNext())
73          {
74              ((PosBottomHalf)iter.next())
75                  .contentInserted(offset,length);
76          }
77          iteration = false;
78      } //}}}
79  
80      //{{{ contentRemoved() method
81      public synchronized void contentRemoved(int offset, int length)
82      {
83          if(positions.size() == 0)
84              return;
85  
86          /* get all positions from offset to the end, inclusive */
87          Iterator iter = positions.tailMap(new PosBottomHalf(offset))
88              .keySet().iterator();
89  
90          iteration = true;
91          while(iter.hasNext())
92          {
93              ((PosBottomHalf)iter.next())
94                  .contentRemoved(offset,length);
95          }
96          iteration = false;
97  
98      } //}}}
99  
100     boolean iteration;
101 
102     //{{{ Private members
103     private JEditBuffer buffer;
104     private SortedMap positions = new TreeMap();
105     //}}}
106 
107     //{{{ Inner classes
108 
109     //{{{ PosTopHalf class
110     class PosTopHalf implements Position  
111     {
112         PosBottomHalf bh;
113 
114         //{{{ PosTopHalf constructor
115         PosTopHalf(PosBottomHalf bh)
116         {
117             this.bh = bh;
118             bh.ref();
119         } //}}}
120 
121         //{{{ getOffset() method
122         public int getOffset()
123         {
124             return bh.offset;
125         } //}}}
126 
127         //{{{ finalize() method
128         protected void finalize()
129         {
130             synchronized(PositionManager.this)
131             {
132                 bh.unref();
133             }
134         } //}}}
135     } //}}}
136 
137     //{{{ PosBottomHalf class
138     class PosBottomHalf implements Comparable  
139     {
140         int offset;
141         int ref;
142 
143         //{{{ PosBottomHalf constructor
144         PosBottomHalf(int offset)
145         {
146             this.offset = offset;
147         } //}}}
148 
149         //{{{ ref() method
150         void ref()
151         {
152             ref++;
153         } //}}}
154 
155         //{{{ unref() method
156         void unref()
157         {
158             if(--ref == 0)
159                 positions.remove(this);
160         } //}}}
161 
162         //{{{ contentInserted() method
163         void contentInserted(int offset, int length)
164         {
165             if(offset > this.offset)
166                 throw new ArrayIndexOutOfBoundsException  ();
167             this.offset += length;
168             checkInvariants();
169         } //}}}
170 
171         //{{{ contentRemoved() method
172         void contentRemoved(int offset, int length)
173         {
174             if(offset > this.offset)
175                 throw new ArrayIndexOutOfBoundsException  ();
176             if(this.offset <= offset + length)
177                 this.offset = offset;
178             else
179                 this.offset -= length;
180             checkInvariants();
181         } //}}}
182 
183         //{{{ equals() method
184         public boolean equals(Object   o)
185         {
186             if(!(o instanceof PosBottomHalf))
187                 return false;
188 
189             return ((PosBottomHalf)o).offset == offset;
190         } //}}}
191 
192         //{{{ compareTo() method
193         public int compareTo(Object   o)
194         {
195             if(iteration)
196                 Log.log(Log.ERROR,this,"Consistency failure");
197             return offset - ((PosBottomHalf)o).offset;
198         } //}}}
199         
200         //{{{ checkInvariants() method
201         private void checkInvariants()
202         {
203             if(offset < 0 || offset > buffer.getLength())
204                 throw new ArrayIndexOutOfBoundsException  ();
205         } //}}}
206     } //}}}
207 
208     //}}}
209 }
210
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