| Clover coverage report - clover |
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| Source file | Conditionals | Statements | Methods | TOTAL | |||||||||||||||
| CommandHistory.java | 100% | 94.1% | 87.5% | 93.1% |
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| 1 |
package abbot.editor.actions;
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import java.util.ArrayList;
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/** Keep a history of commands, enabling potentially unlimited undo.
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This class is not synchronized.<p>
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Note that undo is itself an undoable action.<p>
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*/
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public class CommandHistory { |
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private ArrayList list = new ArrayList(); |
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/** The index of the most recent command "undone", or the size of the
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* history if the most recent action was "execute".
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*/
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private int cursor = 0; |
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private Command get(int idx) { |
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return ((Command)list.get(idx));
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} |
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public boolean canUndo() { |
| 23 | 12 |
return cursor > 0 && (get(cursor-1) instanceof Undoable); |
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} |
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public void undo() throws NoUndoException { |
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if (canUndo()) {
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| 28 | 3 |
UndoableCommand undoable = (UndoableCommand)get(--cursor); |
| 29 | 3 |
undoable.undo(); |
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// Add the undo to the end of the history
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list.add(new CommandComplement(undoable));
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} |
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else {
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// Reset the cursor to the end of the history
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cursor = list.size(); |
| 36 | 1 |
throw new NoUndoException(); |
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} |
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} |
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/** Add the given command to the command history. */
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public void add(Command command) { |
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// If the command can't be undone, then clear the undo history
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| 43 | 3 |
if (!(command instanceof Undoable)) { |
| 44 | 2 |
clear(); |
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} |
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| 46 | 3 |
list.add(command); |
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// Put the cursor at the end of the command history
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| 48 | 3 |
cursor = list.size(); |
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} |
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| 51 | 2 |
public void clear() { |
| 52 | 2 |
list.clear(); |
| 53 | 2 |
cursor = 0; |
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} |
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/** Simple wrapper around an existing command to swap the sense of its
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execute/undo.
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*/
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private class CommandComplement implements UndoableCommand { |
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private UndoableCommand cmd;
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public CommandComplement(UndoableCommand orig) {
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cmd = orig; |
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} |
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| 64 | 0 |
public void execute() { |
| 65 | 0 |
cmd.undo(); |
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} |
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| 67 | 1 |
public void undo() { |
| 68 | 1 |
cmd.execute(); |
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} |
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} |
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} |
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