package org.argeo.cms.ui.widgets;
   
   import javax.jcr.Item;
   import javax.jcr.Node;
   import javax.jcr.Property;
   import javax.jcr.RepositoryException;
   import javax.jcr.Session;
   
   import org.argeo.cms.CmsException;
  import org.argeo.cms.ui.util.CmsUiUtils;
  import org.eclipse.swt.SWT;
  import org.eclipse.swt.widgets.Composite;
  
  /** A composite which can (optionally) manage a JCR Item. */
  public class JcrComposite extends Composite {
  	private static final long serialVersionUID = -1447009015451153367L;
  
  	private final Session session;
  
  	private String nodeId;
  	private String property = null;
  	private Node cache;
  
  	/** Regular composite constructor. No layout is set. */
  	public JcrComposite(Composite parent, int style) {
  		super(parent, style);
  		session = null;
  		nodeId = null;
  	}
  
  	public JcrComposite(Composite parent, int style, Item item)
  			throws RepositoryException {
  		this(parent, style, item, false);
  	}
  
  	public JcrComposite(Composite parent, int style, Item item,
  			boolean cacheImmediately) throws RepositoryException {
  		super(parent, style);
  		this.session = item.getSession();
  		if (!cacheImmediately && (SWT.READ_ONLY == (style & SWT.READ_ONLY))) {
  			// (useless?) optimization: we only save a pointer to the session,
  			// not even a reference to the item
  			this.nodeId = null;
  		} else {
  			Node node;
  			Property property = null;
  			if (item instanceof Node) {
  				node = (Node) item;
  			} else {// Property
  				property = (Property) item;
  				if (property.isMultiple())// TODO manage property index
  					throw new CmsException(
  							"Multiple properties not supported yet.");
  				this.property = property.getName();
  				node = property.getParent();
  			}
  			this.nodeId = node.getIdentifier();
  			if (cacheImmediately)
  				this.cache = node;
  		}
  		setLayout(CmsUiUtils.noSpaceGridLayout());
  	}
  
  	public synchronized Node getNode() {
  		try {
  			if (!itemIsNode())
  				throw new CmsException("Item is not a Node");
  			return getNodeInternal();
  		} catch (RepositoryException e) {
  			throw new CmsException("Cannot get node " + nodeId, e);
  		}
  	}
  
  	private synchronized Node getNodeInternal() throws RepositoryException {
  		if (cache != null)
  			return cache;
  		else if (session != null)
  			if (nodeId != null)
  				return session.getNodeByIdentifier(nodeId);
  			else
  				return null;
  		else
  			return null;
  	}
  
  	public synchronized Property getProperty() {
  		try {
  			if (itemIsNode())
  				throw new CmsException("Item is not a Property");
  			Node node = getNodeInternal();
  			if (!node.hasProperty(property))
  				throw new CmsException("Property " + property
  						+ " is not set on " + node);
  			return node.getProperty(property);
  		} catch (RepositoryException e) {
  			throw new CmsException("Cannot get property " + property
  					+ " from node " + nodeId, e);
  		}
  	}
 
 	public synchronized Boolean itemIsNode() {
 		return property == null;
 	}
 
 	/** Set/update the cache or change the node */
 	public synchronized void setNode(Node node) throws RepositoryException {
 		if (!itemIsNode())
 			throw new CmsException("Cannot set a Node on a Property");
 
 		if (node == null) {// clear cache
 			this.cache = null;
 			return;
 		}
 
 		if (session == null || session != node.getSession())// check session
 			throw new CmsException("Uncompatible session");
 
 		if (nodeId == null || !nodeId.equals(node.getIdentifier())) {
 			nodeId = node.getIdentifier();
 			cache = node;
 			itemUpdated();
 		} else {
 			cache = node;// set/update cache
 		}
 	}
 
 	/** Set/update the cache or change the property */
 	public synchronized void setProperty(Property prop)
 			throws RepositoryException {
 		if (itemIsNode())
 			throw new CmsException("Cannot set a Property on a Node");
 
 		if (prop == null) {// clear cache
 			this.cache = null;
 			return;
 		}
 
 		if (session == null || session != prop.getSession())// check session
 			throw new CmsException("Uncompatible session");
 
 		Node node = prop.getNode();
 		if (nodeId == null || !nodeId.equals(node.getIdentifier())
 				|| !property.equals(prop.getName())) {
 			nodeId = node.getIdentifier();
 			property = prop.getName();
 			cache = node;
 			itemUpdated();
 		} else {
 			cache = node;// set/update cache
 		}
 	}
 
 	public synchronized String getNodeId() {
 		return nodeId;
 	}
 
 	/** Change the node, does nothing if same. */
 	public synchronized void setNodeId(String nodeId)
 			throws RepositoryException {
 		if (this.nodeId != null && this.nodeId.equals(nodeId))
 			return;
 		this.nodeId = nodeId;
 		if (cache != null)
 			cache = session.getNodeByIdentifier(this.nodeId);
 		itemUpdated();
 	}
 
 	protected synchronized void itemUpdated() {
 		layout();
 	}
 
 	public Session getSession() {
 		return session;
 	}
 }