1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
|
package tim.prune.undo;
import tim.prune.data.Stack;
import java.util.ArrayList;
import java.util.List;
import tim.prune.cmd.Command;
/**
* Class to hold a command together with a counter
*/
class CommandWithState
{
public final Command _command;
public final int _undoCounter;
/** Constructor */
public CommandWithState(Command inCommand, int inCounter)
{
_command = inCommand;
_undoCounter = inCounter;
}
}
/**
* Stack of undo operations
* which also remembers how many undos have been performed
*/
public class UndoStack extends Stack<CommandWithState>
{
/** Number of undos (and clears) already performed */
private int _numUndos = 0;
public synchronized void clear()
{
_numUndos++;
super.clear();
}
/** Add a command to the stack */
public synchronized void add(Command inCommand) {
super.add(new CommandWithState(inCommand, _numUndos));
}
/** Pop the latest command from the stack */
public synchronized Command popCommand()
{
_numUndos++;
return super.pop()._command;
}
/** Get the list of command descriptions, starting with the most recently added */
public List<String> getDescriptions()
{
ArrayList<String> commands = new ArrayList<>();
for (CommandWithState cws : asList()) {
commands.add(cws._command.getDescription());
}
return commands;
}
/** @return number of undos */
public int getNumUndos()
{
if (isEmpty()) {return 0;}
// Get the number of undos stored by the last operation on the stack
return peek()._undoCounter;
}
}
|
