TreeLoader.java

/*
 * Copyright (C) 2002-2004 Colin Bell
 * colbell@users.sourceforge.net
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write toS the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package net.sourceforge.squirrel_sql.client.session.mainpanel.objecttree;

import java.sql.SQLException;
import java.util.Iterator;
import java.util.List;

import javax.swing.tree.TreePath;

import net.sourceforge.squirrel_sql.client.session.ISession;
import net.sourceforge.squirrel_sql.fw.gui.GUIUtils;
import net.sourceforge.squirrel_sql.fw.sql.DatabaseObjectInfo;
import net.sourceforge.squirrel_sql.fw.sql.DatabaseObjectType;
import net.sourceforge.squirrel_sql.fw.sql.IDatabaseObjectInfo;
import net.sourceforge.squirrel_sql.fw.util.log.ILogger;
import net.sourceforge.squirrel_sql.fw.util.log.LoggerController;

/**
 * This class actually loads the tree.
 * Note: This class was extracted from {@link ObjectTree} to make it more testable.
 */
public class TreeLoader
{
	
	 /** Logger for this class. */
		private static final ILogger s_log =
			LoggerController.createLogger(TreeLoader.class);
		
	private ObjectTree objectTree;
	private ObjectTreeNode _parentNode;
	private INodeExpander[] _expanders;
	private boolean _selectParentNode;
	private ObjectTreeModel model;
	private ISession session;

	TreeLoader(ISession session, ObjectTree objectTree, ObjectTreeModel model, ObjectTreeNode parentNode, INodeExpander[] expanders,
				boolean selectParentNode)
	{
		super();
		this.session = session;
		this.objectTree = objectTree;
		this.model = model;
		_parentNode = parentNode;
		_expanders = expanders;
		_selectParentNode= selectParentNode;
	}

	void execute()
	{
		try
		{
			try
			{
				ObjectTreeNode loadingNode = showLoadingNode();
				try
				{
					loadChildren();
				}
				finally
				{
                    if (_parentNode.isNodeChild(loadingNode)){
                        _parentNode.remove(loadingNode);
                    }
				}
			}
			finally
			{
				fireStructureChanged(_parentNode);
				if (_selectParentNode)
				{
					this.objectTree.clearSelection();
					this.objectTree.setSelectionPath(new TreePath(_parentNode.getPath()));
				}
			}
		}
		catch (Throwable ex)
		{
			final String msg = "Error: " + _parentNode.toString();
			s_log.error(msg, ex);
			this.session.showErrorMessage(msg + ": " + ex.toString());
		}
	}

	/**
	 * This adds a node to the tree that says "Loading..." in order to give
	 * feedback to the user.
	 */
	private ObjectTreeNode showLoadingNode()
	{
		IDatabaseObjectInfo doi = new DatabaseObjectInfo(null, null,
							"Loading...", DatabaseObjectType.OTHER,
							this.session.getSQLConnection().getSQLMetaData());
		ObjectTreeNode loadingNode = new ObjectTreeNode(this.session, doi);
		_parentNode.add(loadingNode);
		fireStructureChanged(_parentNode);
		return loadingNode;
	}

	/**
	 * This expands the parent node and shows all its children.
	 */
	private void loadChildren() throws SQLException
	{
		boolean noChildrenFound = true;
		for (int i = 0; i < _expanders.length; ++i)
		{
			boolean nodeTypeAllowsChildren = false;
			DatabaseObjectType lastDboType = null;
			List<ObjectTreeNode> list = _expanders[i].createChildren(this.session, _parentNode);
			
			if(list.isEmpty() == false){
				noChildrenFound = false;
			}
			
			Iterator<ObjectTreeNode> it = list.iterator();
			while (it.hasNext())
			{
				Object nextObj = it.next();
				if (nextObj instanceof ObjectTreeNode)
				{
					ObjectTreeNode childNode = (ObjectTreeNode)nextObj;
					if (childNode.getExpanders().length >0)
					{
						childNode.setAllowsChildren(true);
					}
					else
					{
						DatabaseObjectType childNodeDboType = childNode.getDatabaseObjectType();
						if (childNodeDboType != lastDboType)
						{
							this.objectTree.getTypedModel().addKnownDatabaseObjectType(childNodeDboType);
							lastDboType = childNodeDboType;
							if (this.model.getExpanders(childNodeDboType).length > 0)
							{
								nodeTypeAllowsChildren = true;
							}
							else
							{
								nodeTypeAllowsChildren = false;
							}
						}
						childNode.setAllowsChildren(nodeTypeAllowsChildren);
					}
					_parentNode.add(childNode);
				}
			}
		}

		// We cann't use getChildCount, because the node has a temporary child called "Loading..."
		_parentNode.setNoChildrenFoundWithExpander(noChildrenFound);
	}

	/**
	 * Let the object tree model know that its structure has changed.
	 */
	private void fireStructureChanged(final ObjectTreeNode node)
	{
		GUIUtils.processOnSwingEventThread(new Runnable()
		{
			public void run()
			{
				model.nodeStructureChanged(node);
			}
		});
	}
}