package org.argeo.cms.ui.viewers;
   
   import java.util.Observable;
   
   import javax.jcr.Node;
   import javax.jcr.RepositoryException;
   import javax.jcr.Session;
   import javax.jcr.nodetype.NodeType;
   import javax.jcr.version.VersionManager;
  
  import org.argeo.cms.CmsException;
  import org.argeo.cms.ui.CmsEditable;
  import org.argeo.cms.ui.CmsEditionEvent;
  import org.eclipse.rap.rwt.RWT;
  import org.eclipse.swt.SWT;
  import org.eclipse.swt.widgets.Display;
  import org.eclipse.swt.widgets.Event;
  import org.eclipse.swt.widgets.Listener;
  
  /** Provides the CmsEditable semantic based on JCR versioning. */
  public class JcrVersionCmsEditable extends Observable implements CmsEditable {
  	private final String nodePath;// cache
  	private final VersionManager versionManager;
  	private final Boolean canEdit;
  
  	public JcrVersionCmsEditable(Node node) throws RepositoryException {
  		this.nodePath = node.getPath();
  		if (node.getSession().hasPermission(node.getPath(),
  				Session.ACTION_SET_PROPERTY)) {
  			// was Session.ACTION_ADD_NODE
  			canEdit = true;
  			if (!node.isNodeType(NodeType.MIX_VERSIONABLE)) {
  				node.addMixin(NodeType.MIX_VERSIONABLE);
  				node.getSession().save();
  			}
  			versionManager = node.getSession().getWorkspace()
  					.getVersionManager();
  		} else {
  			canEdit = false;
  			versionManager = null;
  		}
  
  		// bind keys
  		if (canEdit) {
  			Display display = Display.getCurrent();
  			display.setData(RWT.ACTIVE_KEYS, new String[] { "CTRL+RETURN",
  					"CTRL+E" });
  			display.addFilter(SWT.KeyDown, new Listener() {
  				private static final long serialVersionUID = -4378653870463187318L;
  
  				public void handleEvent(Event e) {
  					boolean ctrlPressed = (e.stateMask & SWT.CTRL) != 0;
  					if (ctrlPressed && e.keyCode == '\r')
  						stopEditing();
  					else if (ctrlPressed && e.keyCode == 'E')
  						stopEditing();
  				}
  			});
  		}
  	}
  
  	@Override
  	public Boolean canEdit() {
  		return canEdit;
  	}
  
  	public Boolean isEditing() {
  		try {
  			if (!canEdit())
  				return false;
  			return versionManager.isCheckedOut(nodePath);
  		} catch (RepositoryException e) {
  			throw new CmsException("Cannot check whether " + nodePath
  					+ " is editing", e);
  		}
  	}
  
  	@Override
  	public void startEditing() {
  		try {
  			versionManager.checkout(nodePath);
  			setChanged();
  		} catch (RepositoryException e1) {
  			throw new CmsException("Cannot publish " + nodePath);
  		}
  		notifyObservers(new CmsEditionEvent(nodePath,
  				CmsEditionEvent.START_EDITING));
  	}
  
  	@Override
  	public void stopEditing() {
  		try {
  			versionManager.checkin(nodePath);
  			setChanged();
  		} catch (RepositoryException e1) {
  			throw new CmsException("Cannot publish " + nodePath, e1);
  		}
  		notifyObservers(new CmsEditionEvent(nodePath,
  				CmsEditionEvent.STOP_EDITING));
 	}
 }