ModelNodePersistableURIProvider.java

/*******************************************************************************
 * Copyright (c) 2011, 2012 Wind River Systems, Inc. and others. All rights reserved.
 * This program and the accompanying materials are made available under the terms
 * of the Eclipse Public License v1.0 which accompanies this distribution, and is
 * available at http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 * Wind River Systems - initial API and implementation
 *******************************************************************************/
package org.eclipse.tcf.te.core.adapters;

import java.net.URI;

import org.eclipse.core.runtime.Assert;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.Path;
import org.eclipse.core.runtime.Platform;
import org.eclipse.tcf.te.core.activator.CoreBundleActivator;
import org.eclipse.tcf.te.runtime.model.interfaces.IModelNode;
import org.eclipse.tcf.te.runtime.model.interfaces.IModelNodeProvider;
import org.eclipse.tcf.te.runtime.persistence.interfaces.IPersistableNameProvider;
import org.eclipse.tcf.te.runtime.persistence.interfaces.IPersistableNodeProperties;
import org.eclipse.tcf.te.runtime.persistence.interfaces.IPersistableURIProvider;

/**
 * Model node persistable adapter implementation.
 */
public class ModelNodePersistableURIProvider implements IPersistableURIProvider {

	/**
	 * Determine the model node from the given context object.
	 *
	 * @param context The context object or <code>null</code>.
	 * @return The model node or <code>null</code>.
	 */
	private IModelNode getModelNode(Object context) {
		IModelNode node = null;

		if (context instanceof IModelNode) {
			node = (IModelNode)context;
		}
		else if (context instanceof IModelNodeProvider) {
			node = ((IModelNodeProvider)context).getModelNode();
		}

		return node;
	}

	/* (non-Javadoc)
	 * @see org.eclipse.tcf.te.runtime.persistence.interfaces.IPersistableURIProvider#getURI(java.lang.Object)
	 */
	@Override
	public URI getURI(Object context) {
		Assert.isNotNull(context);

		URI uri = null;

		IModelNode node = getModelNode(context);

		// Only model nodes are supported
		if (node != null) {

			IPath path = null;

			// Try to adapt the node to the IPersistableNameProvider interface first
			IPersistableNameProvider provider = (IPersistableNameProvider)node.getAdapter(IPersistableNameProvider.class);
			if (provider != null) {
				String name = provider.getName(node);
				if (name != null && !"".equals(name.trim())) { //$NON-NLS-1$
					path = getRoot().append(name.trim());
				}
			}

			if (path == null) {
				// If the path could not be determined via the IPersistableNameProvider interface, check for the node id
				if (node.getStringProperty(IModelNode.PROPERTY_ID) != null && !"".equals(node.getStringProperty(IModelNode.PROPERTY_ID).trim())) { //$NON-NLS-1$
					path = getRoot().append(makeValidFileSystemName(node.getStringProperty(IModelNode.PROPERTY_ID).trim()));
				}
				// If the id is not set, check for the node name
				else if (node.getName() != null && !"".equals(node.getName().trim())) { //$NON-NLS-1$
					path = getRoot().append(makeValidFileSystemName(node.getName().trim()));
				}
				// If the name is not set, check for an URI
				else if (node.getProperty(IPersistableNodeProperties.PROPERTY_URI) != null) {
					Object candidate = node.getProperty(IPersistableNodeProperties.PROPERTY_URI);
					if (candidate instanceof URI) {
						uri = (URI)candidate;
					}
					else if (candidate instanceof String && !"".equals(((String)candidate).trim())) { //$NON-NLS-1$
						uri = URI.create(((String)candidate).trim());
					}
				}
				// No name and no explicit path is set -> use the UUID
				else if (node.getUUID() != null) {
					path = getRoot().append(makeValidFileSystemName(node.getUUID().toString().trim()));
				}
			}

			if (path != null) {
				if (!"json".equals(path.getFileExtension())) { //$NON-NLS-1$
					path = path.addFileExtension("json"); //$NON-NLS-1$
				}
				uri = path.toFile().toURI();
			}
		}

		return uri;
	}

	/**
	 * Make a valid file system name from the given name.
	 *
	 * @param name The original name. Must not be <code>null</code>.
	 * @return The valid file system name.
	 */
	protected String makeValidFileSystemName(String name) {
		Assert.isNotNull(name);
		return name.replaceAll("\\W", "_"); //$NON-NLS-1$ //$NON-NLS-2$
	}

	/**
	 * Returns the root location.
	 *
	 * @return The root location or <code>null</code> if it cannot be determined.
	 */
	protected IPath getRoot() {
		IPath location = null;

		// Try the bundles state location first (not available if launched with -data @none).
		try {
			IPath path = Platform.getStateLocation(CoreBundleActivator.getContext().getBundle()).append(".store"); //$NON-NLS-1$
			boolean exists = path.toFile().exists();
			if (!exists) exists = path.toFile().mkdirs();
			if (exists && path.toFile().canRead() && path.toFile().isDirectory()) {
				location = path;
			}
		} catch (IllegalStateException e) {
			// Workspace less environments (-data @none)
			// The users local target definition persistence directory is $HOME/.tcf/.store.
			IPath path = new Path(System.getProperty("user.home")).append(".tcf/.store"); //$NON-NLS-1$ //$NON-NLS-2$
			boolean exists = path.toFile().exists();
			if (!exists) exists = path.toFile().mkdirs();
			if (exists && path.toFile().canRead() && path.toFile().isDirectory()) {
				location = path;
			}
		}

		return location;
	}
}