UndoableChangeTempo.java

package org.herac.tuxguitar.gui.undo.undoables.custom;

import java.util.ArrayList;
import java.util.List;

import org.herac.tuxguitar.gui.TuxGuitar;
import org.herac.tuxguitar.gui.undo.CannotRedoException;
import org.herac.tuxguitar.gui.undo.CannotUndoException;
import org.herac.tuxguitar.gui.undo.UndoableEdit;
import org.herac.tuxguitar.gui.undo.undoables.UndoableCaretHelper;
import org.herac.tuxguitar.song.models.TGMeasureHeader;
import org.herac.tuxguitar.song.models.TGTempo;

public class UndoableChangeTempo implements UndoableEdit {
  public static UndoableChangeTempo startUndo() {
    UndoableChangeTempo undoable = new UndoableChangeTempo();
    undoable.doAction = UNDO_ACTION;
    undoable.undoCaret = new UndoableCaretHelper();
    undoable.getTempos(undoable.undoableTempos);
    return undoable;
  }

  private int doAction;
  private List<TGTempo> redoableTempos;
  private UndoableCaretHelper redoCaret;
  private List<TGTempo> undoableTempos;

  private UndoableCaretHelper undoCaret;

  private UndoableChangeTempo() {
    super();
    this.undoableTempos = new ArrayList<TGTempo>();
    this.redoableTempos = new ArrayList<TGTempo>();
  }

  public boolean canRedo() {
    return (this.doAction == REDO_ACTION);
  }

  public boolean canUndo() {
    return (this.doAction == UNDO_ACTION);
  }

  public UndoableChangeTempo endUndo() {
    this.redoCaret = new UndoableCaretHelper();
    this.getTempos(this.redoableTempos);
    return this;
  }

  private void getTempos(List<TGTempo> list) {
    for (final TGMeasureHeader header : TuxGuitar.instance().getSongManager()
        .getSong().getMeasureHeaders()) {
      list.add(header.getTempo().clone());
    }
  }

  public void redo() throws CannotRedoException {
    if (!canRedo()) {
      throw new CannotRedoException();
    }
    this.setTempos(this.redoableTempos);
    this.redoCaret.update();

    this.doAction = UNDO_ACTION;
  }

  private void setTempos(List<TGTempo> tempos) {
    int length = tempos.size();
    if (length != TuxGuitar.instance().getSongManager().getSong()
        .countMeasureHeaders()) {
      return;
    }
    for (int i = 0; i < length; i++) {
      TGTempo tempo = tempos.get(i).clone();
      TuxGuitar.instance().getSongManager().changeTempo(
          TuxGuitar.instance().getSongManager().getMeasureHeader(i + 1), tempo);
    }
    TuxGuitar.instance().fireUpdate();
  }

  public void undo() throws CannotUndoException {
    if (!canUndo()) {
      throw new CannotUndoException();
    }
    this.setTempos(this.undoableTempos);
    this.undoCaret.update();

    this.doAction = REDO_ACTION;
  }
}