UndoOperationAction.java

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package edu.rice.cs.hpc.traceviewer.operation;

import org.eclipse.core.commands.ExecutionException;
import org.eclipse.core.commands.operations.IUndoableOperation;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.jface.action.Action;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Menu;

/***********************************************************************
 * 
 * Class to manage undo operations such as region change, depth change
 *  or processes pattern change
 * 
 * $Id: UndoOperationAction.java 1556 2013-01-02 21:11:12Z laksono $
 *
 ***********************************************************************/
public class UndoOperationAction extends OperationHistoryAction {

    
    public UndoOperationAction(ImageDescriptor img) {
        super(img);
    }

    @Override
    protected IUndoableOperation[] getHistory() {
        return TraceOperation.getUndoHistory();
    }

    @Override
    protected void execute() {
        IUndoableOperation[] operations = getHistory();
        if (operations.length<1)
            return;
        
        IUndoableOperation[] redos = TraceOperation.getRedoHistory();
        
        if (redos.length == 0) {
            // hack: when there's no redo, we need to remove the current
            // history into the redo's stack. To do this properly, we
            // should perform an extra undo before the real undo

            doUndo();
        }
        doUndo();
        //execute(operations[operations.length-1]);
    }

    /***
     * helper method to perform the default undo
     */
    private void doUndo() {
        try {
            IStatus status = TraceOperation.getOperationHistory().
                    undo(TraceOperation.undoableContext, null, null);
            if (!status.isOK()) {
                System.err.println("Cannot undo: " + status.getMessage());
            }
        } catch (ExecutionException e) {
            e.printStackTrace();
        }
    }
    
    @Override
    protected void execute(IUndoableOperation operation) {
        try {
            TraceOperation.getOperationHistory().undoOperation(operation, null, null);
        } catch (ExecutionException e) {
            e.printStackTrace();
        }
    }

    @Override
    public Menu getMenu(Control parent) {
        Menu menu = getMenu();
        if (menu != null) 
            menu.dispose();
        
        menu = new Menu(parent);
        
        IUndoableOperation[] operations = getHistory();
        
        // create a list of menus of undoable operations
        for (int i=operations.length-1; i>=0; i--) {
            final IUndoableOperation op = operations[i];
            Action action = new Action(op.getLabel()) {
                public void run() {
                    execute(op);
                }
            };
            addActionToMenu(menu, action);
        } 
        return menu;
    }

    @Override
    protected IUndoableOperation[] setStatus() {
        final IUndoableOperation []ops = getHistory(); 
        //debug("undo", ops);
        
        boolean status = (ops != null) && (ops.length>0);
        setEnabled(status);
        return ops;
    }
}