bundles/org.simantics.ui/src/org/simantics/ui/workbench/handler/e4/UndoRedoTester.java

   1 package org.simantics.ui.workbench.handler.e4;
   2
   3 import org.eclipse.swt.widgets.Display;
   4 import org.eclipse.ui.PlatformUI;
   5 import org.eclipse.ui.contexts.IContextActivation;
   6 import org.eclipse.ui.contexts.IContextService;
   7 import org.simantics.DatabaseJob;
   8 import org.simantics.Simantics;
   9 import org.simantics.db.Session;
  10 import org.simantics.db.UndoContext;
  11 import org.simantics.db.exception.DatabaseException;
  12 import org.simantics.db.management.ISessionContext;
  13 import org.simantics.db.service.UndoRedoSupport;
  14 import org.simantics.ui.SimanticsUI;
  15 import org.simantics.utils.ui.ErrorLogger;
  16 import org.simantics.utils.ui.SWTUtils;
  17
  18 public class UndoRedoTester {
  19
  20     private static final boolean DEBUG = false;
  21     private static final String SIMANTICS_UNDO_CONTEXT = "org.simantics.ui.undoContext";
  22     public static final String UNDO_ENABLED = "org.simantics.undo.enabled";
  23
  24     private static UndoRedoSupport undoSupport = null;
  25     private static UndoChangeListener changeListener = new UndoChangeListener();
  26     private static IContextActivation activation = null;
  27
  28     private static class UndoChangeListener implements UndoRedoSupport.ChangeListener {
  29
  30         private int oldUndo = 0;
  31         private int oldRedo = 0;
  32
  33         @Override
  34         public void onChanged() {
  35             if (DEBUG)
  36                 System.out.println("UndoPropertyTester: on change.");
  37             Display display = PlatformUI.getWorkbench().getDisplay();
  38             SWTUtils.asyncExec(display, new Runnable() {
  39                 @Override
  40                 public void run() {
  41                     handleChange();
  42                 }
  43             });
  44         }
  45
  46         private void handleChange() {
  47             int newUndo = oldUndo;
  48             int newRedo = oldRedo;
  49             try {
  50                 ISessionContext ctx = Simantics.getSessionContext();
  51                 if (DEBUG)
  52                     System.out.println("UndoPropertyTester: handle change, ctx=" + ctx);
  53                 if (ctx == null)
  54                     return;
  55                 Session session = ctx.peekSession();
  56                 if (DEBUG)
  57                     System.out.println("UndoPropertyTester: handle change, session=" + session);
  58                 if (session == null)
  59                     return;
  60                 UndoContext uc = undoSupport.getUndoContext(session);
  61                 if (uc == null)
  62                     return;
  63                 newUndo = uc.getAll().size();
  64                 newRedo = uc.getRedoList().size();
  65                 if (DEBUG) {
  66                     System.out.println("on undo change: " + oldUndo + "->" + newUndo);
  67                     System.out.println("on redo change: " + oldRedo + "->" + newRedo);
  68                 }
  69                 boolean undoOn = oldUndo == 0 && newUndo == 1;
  70                 boolean undoOff = oldUndo > 0 && newUndo == 0;
  71                 boolean redoOn = oldRedo == 0 && newRedo == 1;
  72                 boolean redoOff = oldRedo > 0 && newRedo == 0;
  73                 if (undoOn || undoOff || redoOn || redoOff)
  74                     toggleContext();
  75             } catch (DatabaseException e) {
  76                 ErrorLogger.getDefault().logError("Undo/Redo support failed.", e);
  77             }
  78             oldUndo = newUndo;
  79             oldRedo = newRedo;
  80         }
  81         private void toggleContext() {
  82             IContextService contextService = (IContextService)PlatformUI.getWorkbench().getService(IContextService.class);
  83             if (null != activation) {
  84                 if (DEBUG)
  85                     System.out.println("UndoPropertyTester: deactivate.");
  86                 try {
  87                     contextService.deactivateContext(activation);
  88                 } catch (Throwable t) {
  89                     ErrorLogger.getDefault().logError("Undo/Redo support failed.", t);
  90                 }
  91                 activation = null;
  92                 if (DEBUG)
  93                     System.out.println("UndoPropertyTester: deactivated.");
  94             } else {
  95                 if (DEBUG)
  96                     System.out.println("UndoPropertyTester: activate.");
  97                 try {
  98                     activation = contextService.activateContext(SIMANTICS_UNDO_CONTEXT);
  99                 } catch (Throwable t) {
 100                     ErrorLogger.getDefault().logError("Undo/Redo support failed.", t);
 101                     activation = null;
 102                 }
 103                 if (DEBUG)
 104                     System.out.println("UndoPropertyTester: activated=" + activation);
 105             }
 106         }
 107
 108     }
 109
 110     private UndoRedoTester() {
 111     }
 112
 113     public static boolean canUndo() {
 114         String undoEnabled = System.getProperty(UNDO_ENABLED);
 115         if(undoEnabled != null && "false".equals(undoEnabled))
 116             return false;
 117
 118         ISessionContext ctx = Simantics.getSessionContext();
 119         if (ctx == null) {
 120             if (DEBUG)
 121                 System.out.println("UndoPropertyTester: no can do undo.");
 122             return false;
 123         }
 124         try {
 125             Session s = ctx.peekSession();
 126             if (null == s) {
 127                 if (DEBUG)
 128                     System.out.println("UndoPropertyTester: session is null, no can do undo.");
 129                 return false;
 130             }
 131             if (DatabaseJob.inProgress())
 132                 return true;
 133             if (null == undoSupport) {
 134                 undoSupport = s.getService(UndoRedoSupport.class);
 135                 undoSupport.subscribe(changeListener);
 136             }
 137             UndoContext uc = undoSupport.getUndoContext(s);
 138             if (uc == null)
 139                 return false;
 140             boolean ret = !uc.getAll().isEmpty();
 141             if (DEBUG)
 142                 System.out.println("UndoPropertyTester: " + (ret ? "" : "no ")+ "can do undo.");
 143             return ret;
 144         } catch (Exception e) {
 145             ErrorLogger.getDefault().logError("Undo/Redo support failed.", e);
 146             if (DEBUG)
 147                 System.out.println("UndoPropertyTester: no can do undo");
 148             return false;
 149         }
 150     }
 151
 152     public static boolean canRedo() {
 153         ISessionContext ctx = Simantics.getSessionContext();
 154         if (ctx == null) {
 155             if (DEBUG)
 156                 System.out.println("UndoPropertyTester: no can do redo.");
 157             return false;
 158         }
 159         try {
 160             Session s = ctx.peekSession();
 161             if (null == s) {
 162                 if (DEBUG)
 163                     System.out.println("UndoPropertyTester: session is null, no can do redo.");
 164                 return false;
 165             }
 166             if (DatabaseJob.inProgress())
 167                 return true;
 168             if (null == undoSupport) {
 169                 undoSupport = s.getService(UndoRedoSupport.class);
 170                 undoSupport.subscribe(changeListener);
 171             }
 172             UndoContext uc = undoSupport.getUndoContext(s);
 173             if (uc == null)
 174                 return false;
 175             boolean ret = !uc.getRedoList().isEmpty();
 176             if (DEBUG)
 177                 System.out.println("UndoPropertyTester: " + (ret ? "" : "no ")+ "can do redo.");
 178             return ret;
 179         } catch (Exception e) {
 180             ErrorLogger.getDefault().logError("Undo/Redo support failed.", e);
 181             if (DEBUG)
 182                 System.out.println("UndoPropertyTester: no can do redo.");
 183             return false;
 184         }
 185     }
 186
 187 }