1.5/plugins/org.eclipse.epf.library.persistence/src/org/eclipse/epf/persistence/util/PersistenceUtil.java - epf/org.eclipse.epf.composer - Git at Google

 //------------------------------------------------------------------------------
 // Copyright (c) 2005, 2006 IBM Corporation 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:
 // IBM Corporation - initial implementation
 //------------------------------------------------------------------------------
 package org.eclipse.epf.persistence.util;

 import java.io.File;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;

 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.DocumentBuilderFactory;
 import javax.xml.parsers.SAXParser;
 import javax.xml.parsers.SAXParserFactory;

 import org.eclipse.core.resources.IResource;
 import org.eclipse.core.runtime.IPath;
 import org.eclipse.core.runtime.OperationCanceledException;
 import org.eclipse.emf.common.CommonPlugin;
 import org.eclipse.emf.common.util.URI;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.EReference;
 import org.eclipse.emf.ecore.resource.Resource;
 import org.eclipse.emf.ecore.resource.ResourceSet;
 import org.eclipse.emf.ecore.util.EcoreUtil;
 import org.eclipse.epf.common.service.versioning.EPFVersions;
 import org.eclipse.epf.common.service.versioning.VersionUtil;
 import org.eclipse.epf.library.persistence.ILibraryResource;
 import org.eclipse.epf.library.persistence.ILibraryResourceSet;
 import org.eclipse.epf.persistence.FileManager;
 import org.eclipse.epf.persistence.MultiFileResourceSetImpl;
 import org.eclipse.epf.persistence.MultiFileSaveUtil;
 import org.eclipse.epf.persistence.PersistencePlugin;
 import org.eclipse.epf.persistence.migration.internal.Migrator;
 import org.eclipse.epf.persistence.refresh.internal.RefreshEvent;
 import org.eclipse.epf.uma.ContentDescription;
 import org.eclipse.epf.uma.DescribableElement;
 import org.eclipse.epf.uma.MethodElement;
 import org.eclipse.epf.uma.MethodLibrary;
 import org.eclipse.epf.uma.UmaPackage;
 import org.osgi.framework.Version;
 import org.w3c.dom.Document;
 import org.w3c.dom.Element;
 import org.xml.sax.Attributes;
 import org.xml.sax.SAXException;
 import org.xml.sax.helpers.DefaultHandler;

 /**
  * Utility class with static helper methods for library persistence
  *
  * @author Phong Nguyen Le
  * @since 1.0
  */
 public class PersistenceUtil {

 	/**
 	 * Gets the current namespace URI of UMA.
 	 */
 	public static final String getUMANsURI() {
 		return UmaPackage.eNS_URI;
 	}

 	public static final String getUMANsURI(String libPath) {
 		try {
 			DocumentBuilder builder = DocumentBuilderFactory.newInstance()
 					.newDocumentBuilder();
 			Document doc = builder.parse(new File(libPath));
 			Element root = doc.getDocumentElement();
 			String nsURI = root.getAttribute("xmlns:com.ibm.uma"); //$NON-NLS-1$
 			if (nsURI == null || nsURI.equals("")) { //$NON-NLS-1$
 				nsURI = root.getAttribute("xmlns:org.eclipse.epf.uma"); //$NON-NLS-1$
 			}
 			if (nsURI == null || nsURI.equals("")) { //$NON-NLS-1$
 				nsURI = root.getAttribute("xmlns:uma") + "/uma.ecore"; //$NON-NLS-1$ //$NON-NLS-2$
 			}
 			return nsURI;
 		} catch (Exception e) {
 			throw new RuntimeException(e);
 		}
 	}

 	public static final boolean conversionRequired(String libPath) {
 		String currentNsURI = PersistenceUtil.getUMANsURI();
 		String libNsURI = PersistenceUtil.getUMANsURI(libPath);
 		if (currentNsURI.equals(libNsURI))
 			return false;
 		if (Migrator.OLD_UMA_NS_URI.equals(libNsURI))
 			return true;
 		return false;
 	}

 	public static final IResource getWorkspaceResource(Object obj) {
 		Resource resource = null;
 		if (obj instanceof DescribableElement) {
 			DescribableElement e = (DescribableElement) obj;
 			ContentDescription content = e.getPresentation();
 			resource = content.eResource();
 			if (resource == null) {
 				resource = e.eResource();
 			}
 		} else if (obj instanceof EObject) {
 			resource = ((EObject) obj).eResource();
 		} else if (obj instanceof Resource) {
 			resource = (Resource) obj;
 		}
 		if (resource != null && resource.getURI().isFile()) {
 			return FileManager.getResourceForLocation(resource.getURI()
 					.toFileString());
 		}
 		return null;
 	}

 	public static final Collection<EObject> getProxies(EObject obj) {
 		Collection<EObject> proxies = new ArrayList<EObject>();
 		for (Iterator iter = obj.eAllContents(); iter.hasNext();) {
 			EObject o = (EObject) iter.next();
 			if (o.eIsProxy()) {
 				proxies.add(o);
 			}
 		}
 		return proxies;
 	}

 	/**
 	 * Checks the primary tool version stored in the given resource
 	 *
 	 * @param resource
 	 * @return <li> < 0 if the version of the primary tool stored in the given resource is missing or older than current
 	 *         <li> 0 if the primary tool version in the given resource matches the current version
 	 *         <li> > 0 if  the primary tool version in the given resource is newer than the current version
 	 */
 	public static final int checkToolVersion(Resource resource) {
 		File file = new File(resource.getURI().toFileString());
 		Map fileVersionMap = VersionUtil.readVersionsFromFile(file);
 		if(fileVersionMap != null) {
 			String version = (String) fileVersionMap.get(VersionUtil.getPrimaryToolID());
 			if(version != null) {
 				EPFVersions versions = VersionUtil.getVersions(VersionUtil.getPrimaryToolID());
 				return versions.getCurrentVersion().compareToolVersionTo(new Version(version));
 			}
 		}
 		return -1;
 	}

 	/**
 	 * Gets the first method element in contents of the given resource.
 	 *
 	 * @param resource
 	 * @return
 	 */
 	public static MethodElement getMethodElement(Resource resource) {
 		for (Iterator iter = resource.getContents().iterator(); iter.hasNext();) {
 			Object element = iter.next();
 			if (element instanceof MethodElement) {
 				return (MethodElement) element;
 			}
 		}
 		return null;
 	}

 	/**
 	 * Resolves the proxy and its containers
 	 *
 	 * @param proxy
 	 * @return
 	 */
 	public static EObject resolve(EObject proxy, ResourceSet resourceSet) {
 		EObject resolved;
 		try {
 			resolved = EcoreUtil.resolve(proxy, resourceSet);
 		} catch (Exception e) {
 			resolved = proxy;
 		}
 		EObject container = proxy.eContainer();
 		if (resolved.eContainer() == null && container != null) {
 			if (container.eIsProxy()) {
 				container = resolve(container, resourceSet);
 			}
 			EReference ref = proxy.eContainmentFeature();
 			if (ref.isMany()) {
 				List values = (List) container.eGet(ref);
 				for (Iterator iter = values.iterator(); iter.hasNext(); iter
 						.next())
 					;
 			} else {
 				container.eGet(ref);
 			}
 		}
 		return resolved;
 	}

 	public static Resource getResource(IPath path, ResourceSet resourceSet) {
 		return getResource(path.toOSString(), resourceSet);
 	}

 	public static Resource getResource(String path, ResourceSet resourceSet) {
 		File file = new File(path);
 		for (Resource resource : new ArrayList<Resource>(resourceSet.getResources())) {
 			URI finalURI = MultiFileSaveUtil.getFinalURI(resource);
 			if(finalURI.isFile() && file.equals(new File(finalURI.toFileString()))) {
 				return resource;
 			}
 		}
 		return null;
 	}

 	/**
 	 * Resolves container of the MethodElement in the given resource.
 	 *
 	 * @param resource
 	 */
 	public static void resolveContainer(Resource resource) {
 		ResourceSet resourceSet = resource.getResourceSet();
 		if(resourceSet instanceof MultiFileResourceSetImpl) {
 			((MultiFileResourceSetImpl)resourceSet).resolveContainer(resource);
 		}
 	}

 	public static MethodElement getMethodElement(IResource iResource, ResourceSet resourceSet) {
 		MethodElement element = null;
 		URI uri = URI.createFileURI(iResource.getLocation().toOSString());
 		Resource resource = resourceSet.getResource(uri, true);
 		if (resource != null) {
 			if(resourceSet instanceof MultiFileResourceSetImpl) {
 				((MultiFileResourceSetImpl)resourceSet).resolveContainer(resource);
 			}
 			element = PersistenceUtil.getMethodElement(resource);
 			if (element instanceof ContentDescription) {
 				EObject container = ((ContentDescription)element).eContainer();
 				if (container instanceof MethodElement) {
 					element = (MethodElement)container;
 				}
 			}
 		}
 		return element;
 	}

 	public static void loadAllLibraryResources(MethodLibrary lib) {
 		for (Iterator iter = lib.eAllContents(); iter.hasNext();) {
 			EObject element = (EObject) iter.next();
 			if (element instanceof MethodElement) {
 				try {
 					for (Iterator iterator = element.eCrossReferences()
 							.iterator(); iterator.hasNext();) {
 						iterator.next();
 					}
 				} catch (Exception e) {
 					CommonPlugin.INSTANCE.log(e);
 				}
 			}
 		}
 	}

 	public static String getTopAttribute(File file, final String attributeName) {
 		// Create the SAX parser factory.
 		SAXParserFactory spf = SAXParserFactory.newInstance();

 		// Create the SAX parser.
 		try {
 			SAXParser saxParser = spf.newSAXParser();
 			final String[] valueHolder = new String[1];
 			try {
 			saxParser.parse(file, new DefaultHandler() {
 				private boolean started;
 				@Override
 				public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
 					if(started) {
 						throw new OperationCanceledException();
 					}
 //					System.out.println("uri: " + uri);
 //					System.out.println("localName: " + localName);
 //					System.out.println("qName: " + qName);
 					valueHolder[0] = attributes.getValue(attributeName);
 					started = true;
 				}
 			});
 			}
 			catch(OperationCanceledException e) {
 				//
 			}
 			return valueHolder[0];
 		} catch (Exception e) {
 			PersistencePlugin.getDefault().getLogger().logError(e);
 		}
 		return null;
 	}

 	public static void unload(Collection<Resource> removedResources) {
 		Map<MultiFileResourceSetImpl, Collection<Resource>> resourceSetToUnloadedResourcesMap = new HashMap<MultiFileResourceSetImpl, Collection<Resource>>();
 		for (Resource resource : removedResources) {
 			ResourceSet resourceSet = resource.getResourceSet();
 			boolean unloaded = false;
 			try {
 				if(resourceSet instanceof ILibraryResourceSet) {
 					if(((ILibraryResourceSet)resourceSet).unload(resource, Collections.EMPTY_MAP)) {
 						resourceSet.getResources().remove(resource);
 						unloaded = true;
 					}
 				}
 				else {
 					if(resource.isLoaded()) {
 						resource.unload();
 						unloaded = true;
 					}
 					if(resourceSet != null) {
 						resourceSet.getResources().remove(resource);
 					}
 				}
 			} catch (Exception e) {
 				PersistencePlugin.getDefault().getLogger().logError(e);
 			}
 			if(unloaded && resourceSet instanceof MultiFileResourceSetImpl) {
 				Collection<Resource> unloadedResources = resourceSetToUnloadedResourcesMap.get(resourceSet);
 				if(unloadedResources == null) {
 					unloadedResources = new ArrayList<Resource>();
 					resourceSetToUnloadedResourcesMap.put((MultiFileResourceSetImpl) resourceSet, unloadedResources);
 				}
 				unloadedResources.add(resource);
 			}
 		}
 		for (Map.Entry<MultiFileResourceSetImpl, Collection<Resource>> entry : resourceSetToUnloadedResourcesMap.entrySet()) {
 			entry.getKey().notifyRefreshListeners(new RefreshEvent(entry.getValue()));
 		}
 	}

 	/**
 	 * Checks if the given method element has a GUID that is the same as GUID of
 	 * one element in the given elements list.
 	 *
 	 * @param e
 	 * @param elements
 	 * @return true if the given method element has duplicate GUID
 	 */
 	public static boolean hasDuplicateGUID(MethodElement e, Collection<? extends MethodElement> elements) {
 		for (MethodElement element : elements) {
 			if(e.getGuid().equals(element.getGuid())) {
 				return true;
 			}
 		}
 		return false;
 	}

 	private static String toPrefix(String path) {
 		return path.endsWith(File.separator) ? path : path + File.separator;
 	}

 	/**
 	 *
 	 * @param resources
 	 * @param oldPrefix
 	 * @param newPrefix
 	 * @return Resources with new URI
 	 */
 	public static Collection<Resource> replaceURIPrefix(Collection<Resource> resources, String oldPrefix, String newPrefix) {
 		URI oldPrefixURI = URI.createFileURI(toPrefix(oldPrefix));
 		URI newPrefixURI = URI.createFileURI(toPrefix(newPrefix));
 		ArrayList<Resource> resourcesWithNewURI = new ArrayList<Resource>();
 		for(Resource resource : resources) {
 			URI uri = resource.getURI();
 			URI newURI = null;
 			try {
 				newURI = uri.replacePrefix(oldPrefixURI, newPrefixURI);
 			}
 			catch(Exception e) {

 			}
 			if(newURI != null && !newURI.equals(resource.getURI())) {
 				resource.setURI(newURI);
 				resourcesWithNewURI.add(resource);
 			}
 		}
 		return resourcesWithNewURI;
 	}

 	public static URI getProxyURI(EObject object) {
 		Resource resource = object.eResource();
 		URI uri = null;
 		if(resource instanceof ILibraryResource) {
 			ILibraryResource libResource = (ILibraryResource) resource;
 			uri = libResource.getProxyURI(object);
 		}
 		else {
 			uri = resource.getURI().appendFragment(resource.getURIFragment(object));
 		}
 		return uri;
 	}

 	public static MultiFileResourceSetImpl getImportPluginResourceSet() {
 		MultiFileResourceSetImpl resourceSet;
 		resourceSet = new MultiFileResourceSetImpl(false) {
 			protected void demandLoad(Resource resource) throws IOException {
 				if (! skipDemandLoad(resource)) {
 					super.demandLoad(resource);
 				}
 			}
 			private boolean skipDemandLoad(Resource res) {
 				File file = new File(res.getURI().toFileString());
 				if (! file.exists() && file.getName().equals(MultiFileSaveUtil.DEFAULT_PLUGIN_MODEL_FILENAME)) {
 					return true;
 				}
 				return false;
 			}
 		};
 		return resourceSet;
 	}


 	public static void main(String[] args) {
 		String attrib = getTopAttribute(new File(args[0]), args[1]);
 		System.out.println(attrib);
 	}
 }
	//------------------------------------------------------------------------------
	// Copyright (c) 2005, 2006 IBM Corporation 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:
	// IBM Corporation - initial implementation
	//------------------------------------------------------------------------------
	package org.eclipse.epf.persistence.util;

	import java.io.File;
	import java.io.IOException;
	import java.util.ArrayList;
	import java.util.Collection;
	import java.util.Collections;
	import java.util.HashMap;
	import java.util.Iterator;
	import java.util.List;
	import java.util.Map;

	import javax.xml.parsers.DocumentBuilder;
	import javax.xml.parsers.DocumentBuilderFactory;
	import javax.xml.parsers.SAXParser;
	import javax.xml.parsers.SAXParserFactory;

	import org.eclipse.core.resources.IResource;
	import org.eclipse.core.runtime.IPath;
	import org.eclipse.core.runtime.OperationCanceledException;
	import org.eclipse.emf.common.CommonPlugin;
	import org.eclipse.emf.common.util.URI;
	import org.eclipse.emf.ecore.EObject;
	import org.eclipse.emf.ecore.EReference;
	import org.eclipse.emf.ecore.resource.Resource;
	import org.eclipse.emf.ecore.resource.ResourceSet;
	import org.eclipse.emf.ecore.util.EcoreUtil;
	import org.eclipse.epf.common.service.versioning.EPFVersions;
	import org.eclipse.epf.common.service.versioning.VersionUtil;
	import org.eclipse.epf.library.persistence.ILibraryResource;
	import org.eclipse.epf.library.persistence.ILibraryResourceSet;
	import org.eclipse.epf.persistence.FileManager;
	import org.eclipse.epf.persistence.MultiFileResourceSetImpl;
	import org.eclipse.epf.persistence.MultiFileSaveUtil;
	import org.eclipse.epf.persistence.PersistencePlugin;
	import org.eclipse.epf.persistence.migration.internal.Migrator;
	import org.eclipse.epf.persistence.refresh.internal.RefreshEvent;
	import org.eclipse.epf.uma.ContentDescription;
	import org.eclipse.epf.uma.DescribableElement;
	import org.eclipse.epf.uma.MethodElement;
	import org.eclipse.epf.uma.MethodLibrary;
	import org.eclipse.epf.uma.UmaPackage;
	import org.osgi.framework.Version;
	import org.w3c.dom.Document;
	import org.w3c.dom.Element;
	import org.xml.sax.Attributes;
	import org.xml.sax.SAXException;
	import org.xml.sax.helpers.DefaultHandler;

	/**
	* Utility class with static helper methods for library persistence
	*
	* @author Phong Nguyen Le
	* @since 1.0
	*/
	public class PersistenceUtil {

	/**
	* Gets the current namespace URI of UMA.
	*/
	public static final String getUMANsURI() {
	return UmaPackage.eNS_URI;
	}

	public static final String getUMANsURI(String libPath) {
	try {
	DocumentBuilder builder = DocumentBuilderFactory.newInstance()
	.newDocumentBuilder();
	Document doc = builder.parse(new File(libPath));
	Element root = doc.getDocumentElement();
	String nsURI = root.getAttribute("xmlns:com.ibm.uma"); //$NON-NLS-1$
	if (nsURI == null \|\| nsURI.equals("")) { //$NON-NLS-1$
	nsURI = root.getAttribute("xmlns:org.eclipse.epf.uma"); //$NON-NLS-1$
	}
	if (nsURI == null \|\| nsURI.equals("")) { //$NON-NLS-1$
	nsURI = root.getAttribute("xmlns:uma") + "/uma.ecore"; //$NON-NLS-1$ //$NON-NLS-2$
	}
	return nsURI;
	} catch (Exception e) {
	throw new RuntimeException(e);
	}
	}

	public static final boolean conversionRequired(String libPath) {
	String currentNsURI = PersistenceUtil.getUMANsURI();
	String libNsURI = PersistenceUtil.getUMANsURI(libPath);
	if (currentNsURI.equals(libNsURI))
	return false;
	if (Migrator.OLD_UMA_NS_URI.equals(libNsURI))
	return true;
	return false;
	}

	public static final IResource getWorkspaceResource(Object obj) {
	Resource resource = null;
	if (obj instanceof DescribableElement) {
	DescribableElement e = (DescribableElement) obj;
	ContentDescription content = e.getPresentation();
	resource = content.eResource();
	if (resource == null) {
	resource = e.eResource();
	}
	} else if (obj instanceof EObject) {
	resource = ((EObject) obj).eResource();
	} else if (obj instanceof Resource) {
	resource = (Resource) obj;
	}
	if (resource != null && resource.getURI().isFile()) {
	return FileManager.getResourceForLocation(resource.getURI()
	.toFileString());
	}
	return null;
	}

	public static final Collection<EObject> getProxies(EObject obj) {
	Collection<EObject> proxies = new ArrayList<EObject>();
	for (Iterator iter = obj.eAllContents(); iter.hasNext();) {
	EObject o = (EObject) iter.next();
	if (o.eIsProxy()) {
	proxies.add(o);
	}
	}
	return proxies;
	}

	/**
	* Checks the primary tool version stored in the given resource
	*
	* @param resource
	* @return <li> < 0 if the version of the primary tool stored in the given resource is missing or older than current
	* <li> 0 if the primary tool version in the given resource matches the current version
	* <li> > 0 if the primary tool version in the given resource is newer than the current version
	*/
	public static final int checkToolVersion(Resource resource) {
	File file = new File(resource.getURI().toFileString());
	Map fileVersionMap = VersionUtil.readVersionsFromFile(file);
	if(fileVersionMap != null) {
	String version = (String) fileVersionMap.get(VersionUtil.getPrimaryToolID());
	if(version != null) {
	EPFVersions versions = VersionUtil.getVersions(VersionUtil.getPrimaryToolID());
	return versions.getCurrentVersion().compareToolVersionTo(new Version(version));
	}
	}
	return -1;
	}

	/**
	* Gets the first method element in contents of the given resource.
	*
	* @param resource
	* @return
	*/
	public static MethodElement getMethodElement(Resource resource) {
	for (Iterator iter = resource.getContents().iterator(); iter.hasNext();) {
	Object element = iter.next();
	if (element instanceof MethodElement) {
	return (MethodElement) element;
	}
	}
	return null;
	}

	/**
	* Resolves the proxy and its containers
	*
	* @param proxy
	* @return
	*/
	public static EObject resolve(EObject proxy, ResourceSet resourceSet) {
	EObject resolved;
	try {
	resolved = EcoreUtil.resolve(proxy, resourceSet);
	} catch (Exception e) {
	resolved = proxy;
	}
	EObject container = proxy.eContainer();
	if (resolved.eContainer() == null && container != null) {
	if (container.eIsProxy()) {
	container = resolve(container, resourceSet);
	}
	EReference ref = proxy.eContainmentFeature();
	if (ref.isMany()) {
	List values = (List) container.eGet(ref);
	for (Iterator iter = values.iterator(); iter.hasNext(); iter
	.next())
	;
	} else {
	container.eGet(ref);
	}
	}
	return resolved;
	}

	public static Resource getResource(IPath path, ResourceSet resourceSet) {
	return getResource(path.toOSString(), resourceSet);
	}

	public static Resource getResource(String path, ResourceSet resourceSet) {
	File file = new File(path);
	for (Resource resource : new ArrayList<Resource>(resourceSet.getResources())) {
	URI finalURI = MultiFileSaveUtil.getFinalURI(resource);
	if(finalURI.isFile() && file.equals(new File(finalURI.toFileString()))) {
	return resource;
	}
	}
	return null;
	}

	/**
	* Resolves container of the MethodElement in the given resource.
	*
	* @param resource
	*/
	public static void resolveContainer(Resource resource) {
	ResourceSet resourceSet = resource.getResourceSet();
	if(resourceSet instanceof MultiFileResourceSetImpl) {
	((MultiFileResourceSetImpl)resourceSet).resolveContainer(resource);
	}
	}

	public static MethodElement getMethodElement(IResource iResource, ResourceSet resourceSet) {
	MethodElement element = null;
	URI uri = URI.createFileURI(iResource.getLocation().toOSString());
	Resource resource = resourceSet.getResource(uri, true);
	if (resource != null) {
	if(resourceSet instanceof MultiFileResourceSetImpl) {
	((MultiFileResourceSetImpl)resourceSet).resolveContainer(resource);
	}
	element = PersistenceUtil.getMethodElement(resource);
	if (element instanceof ContentDescription) {
	EObject container = ((ContentDescription)element).eContainer();
	if (container instanceof MethodElement) {
	element = (MethodElement)container;
	}
	}
	}
	return element;
	}

	public static void loadAllLibraryResources(MethodLibrary lib) {
	for (Iterator iter = lib.eAllContents(); iter.hasNext();) {
	EObject element = (EObject) iter.next();
	if (element instanceof MethodElement) {
	try {
	for (Iterator iterator = element.eCrossReferences()
	.iterator(); iterator.hasNext();) {
	iterator.next();
	}
	} catch (Exception e) {
	CommonPlugin.INSTANCE.log(e);
	}
	}
	}
	}

	public static String getTopAttribute(File file, final String attributeName) {
	// Create the SAX parser factory.
	SAXParserFactory spf = SAXParserFactory.newInstance();

	// Create the SAX parser.
	try {
	SAXParser saxParser = spf.newSAXParser();
	final String[] valueHolder = new String[1];
	try {
	saxParser.parse(file, new DefaultHandler() {
	private boolean started;
	@Override
	public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
	if(started) {
	throw new OperationCanceledException();
	}
	// System.out.println("uri: " + uri);
	// System.out.println("localName: " + localName);
	// System.out.println("qName: " + qName);
	valueHolder[0] = attributes.getValue(attributeName);
	started = true;
	}
	});
	}
	catch(OperationCanceledException e) {
	//
	}
	return valueHolder[0];
	} catch (Exception e) {
	PersistencePlugin.getDefault().getLogger().logError(e);
	}
	return null;
	}

	public static void unload(Collection<Resource> removedResources) {
	Map<MultiFileResourceSetImpl, Collection<Resource>> resourceSetToUnloadedResourcesMap = new HashMap<MultiFileResourceSetImpl, Collection<Resource>>();
	for (Resource resource : removedResources) {
	ResourceSet resourceSet = resource.getResourceSet();
	boolean unloaded = false;
	try {
	if(resourceSet instanceof ILibraryResourceSet) {
	if(((ILibraryResourceSet)resourceSet).unload(resource, Collections.EMPTY_MAP)) {
	resourceSet.getResources().remove(resource);
	unloaded = true;
	}
	}
	else {
	if(resource.isLoaded()) {
	resource.unload();
	unloaded = true;
	}
	if(resourceSet != null) {
	resourceSet.getResources().remove(resource);
	}
	}
	} catch (Exception e) {
	PersistencePlugin.getDefault().getLogger().logError(e);
	}
	if(unloaded && resourceSet instanceof MultiFileResourceSetImpl) {
	Collection<Resource> unloadedResources = resourceSetToUnloadedResourcesMap.get(resourceSet);
	if(unloadedResources == null) {
	unloadedResources = new ArrayList<Resource>();
	resourceSetToUnloadedResourcesMap.put((MultiFileResourceSetImpl) resourceSet, unloadedResources);
	}
	unloadedResources.add(resource);
	}
	}
	for (Map.Entry<MultiFileResourceSetImpl, Collection<Resource>> entry : resourceSetToUnloadedResourcesMap.entrySet()) {
	entry.getKey().notifyRefreshListeners(new RefreshEvent(entry.getValue()));
	}
	}

	/**
	* Checks if the given method element has a GUID that is the same as GUID of
	* one element in the given elements list.
	*
	* @param e
	* @param elements
	* @return true if the given method element has duplicate GUID
	*/
	public static boolean hasDuplicateGUID(MethodElement e, Collection<? extends MethodElement> elements) {
	for (MethodElement element : elements) {
	if(e.getGuid().equals(element.getGuid())) {
	return true;
	}
	}
	return false;
	}

	private static String toPrefix(String path) {
	return path.endsWith(File.separator) ? path : path + File.separator;
	}

	/**
	*
	* @param resources
	* @param oldPrefix
	* @param newPrefix
	* @return Resources with new URI
	*/
	public static Collection<Resource> replaceURIPrefix(Collection<Resource> resources, String oldPrefix, String newPrefix) {
	URI oldPrefixURI = URI.createFileURI(toPrefix(oldPrefix));
	URI newPrefixURI = URI.createFileURI(toPrefix(newPrefix));
	ArrayList<Resource> resourcesWithNewURI = new ArrayList<Resource>();
	for(Resource resource : resources) {
	URI uri = resource.getURI();
	URI newURI = null;
	try {
	newURI = uri.replacePrefix(oldPrefixURI, newPrefixURI);
	}
	catch(Exception e) {

	}
	if(newURI != null && !newURI.equals(resource.getURI())) {
	resource.setURI(newURI);
	resourcesWithNewURI.add(resource);
	}
	}
	return resourcesWithNewURI;
	}

	public static URI getProxyURI(EObject object) {
	Resource resource = object.eResource();
	URI uri = null;
	if(resource instanceof ILibraryResource) {
	ILibraryResource libResource = (ILibraryResource) resource;
	uri = libResource.getProxyURI(object);
	}
	else {
	uri = resource.getURI().appendFragment(resource.getURIFragment(object));
	}
	return uri;
	}

	public static MultiFileResourceSetImpl getImportPluginResourceSet() {
	MultiFileResourceSetImpl resourceSet;
	resourceSet = new MultiFileResourceSetImpl(false) {
	protected void demandLoad(Resource resource) throws IOException {
	if (! skipDemandLoad(resource)) {
	super.demandLoad(resource);
	}
	}
	private boolean skipDemandLoad(Resource res) {
	File file = new File(res.getURI().toFileString());
	if (! file.exists() && file.getName().equals(MultiFileSaveUtil.DEFAULT_PLUGIN_MODEL_FILENAME)) {
	return true;
	}
	return false;
	}
	};
	return resourceSet;
	}


	public static void main(String[] args) {
	String attrib = getTopAttribute(new File(args[0]), args[1]);
	System.out.println(attrib);
	}
	}