How to use org.eclipse.xtext.resource

protected IResourceDescription.Manager getResourceDescriptionManager(URI uri) {
  IResourceServiceProvider resourceServiceProvider = managerRegistry.getResourceServiceProvider(uri);
  if (resourceServiceProvider == null) {
    return null;
  }
  return resourceServiceProvider.getResourceDescriptionManager();
}

public <T> T findService(URI uri, Class<T> serviceClazz) {
  if (thisLanguageServiceProvider.canHandle(uri))
    return thisLanguageServiceProvider.get(serviceClazz);
  IResourceServiceProvider serviceProvider = registry.getResourceServiceProvider(uri);
  if (serviceProvider==null)
    return null;
  final T result = serviceProvider.get(serviceClazz);
  return result;
}

/**
 * This is equal to <code>builder().getOptions()</code>.
 */
public static SaveOptions defaultOptions() {
  return newBuilder().getOptions();
}

private void index(final Resource resource, final URI uri, final ResourceDescriptionsData index) {
 final IResourceServiceProvider serviceProvider = IResourceServiceProvider.Registry.INSTANCE.getResourceServiceProvider(uri);
 if ((serviceProvider != null)) {
  final IResourceDescription resourceDescription = serviceProvider.getResourceDescriptionManager().getResourceDescription(resource);
  if ((resourceDescription != null)) {
   index.addDescription(uri, resourceDescription);
  }
 }
}

public IResourceDescription getResourceDescription(URI uri) {
  Resource resource = resourceSet.getResource(uri, false);
  if (resource == null)
    return null;
  IResourceServiceProvider resourceServiceProvider = registry.getResourceServiceProvider(uri);
  if (resourceServiceProvider == null)
    return null;
  Manager manager = resourceServiceProvider.getResourceDescriptionManager();
  if (manager==null)
    return null;
  return manager.getResourceDescription(resource);
}

@Override
public IResourceDescription getDescription() {
  return xtextResource.getResourceServiceProvider().getResourceDescriptionManager().getResourceDescription(xtextResource);
}

/**
 * @since 2.1 protected
 */
protected URI uri(Object description) {
  if (description instanceof IEObjectDescription) {
    return ((IEObjectDescription) description).getEObjectURI();
  } else if (description instanceof IResourceDescription) {
    return ((IResourceDescription) description).getURI();
  } else if(description instanceof IReferenceDescription) {
    URI containerEObjectURI = ((IReferenceDescription) description).getContainerEObjectURI();
    return containerEObjectURI == null ? ((IReferenceDescription) description).getSourceEObjectUri() : null;
  }
  return null;
}

  public Pair<URI, Integer> apply(URI uri) {
    IResourceServiceProvider serviceProvider = registry.getResourceServiceProvider(uri);
    if (serviceProvider != null) {
      IndexingPriorityProvider priorityProvider = serviceProvider.get(IndexingPriorityProvider.class);
      if (priorityProvider != null)
        return Tuples.create(uri, priorityProvider.getIndexingPriority(resourceSet, uri));
    }
    return Tuples.create(uri, 0);
  }
}));

public void setValidationDisabled(boolean validationDisabled) {
  this.validationDisabled = validationDisabled;
  if (validationDisabled) {
    clearErrorsAndWarnings();
  }
}

/**
 * Performs the actual linking.
 */
protected void superDoLinking() {
  super.doLinking();
}

@Override
public boolean addAll(Collection<? extends Resource> collection) {
  synchronized (lock) {
    return super.addAll(collection);
  }
}

@Override
public boolean retainAll(Collection<?> collection) {
  synchronized (lock) {
    return super.retainAll(collection);
  }
}

@Override
public int indexOf(Object object) {
  synchronized (lock) {
    return super.indexOf(object);
  }
}

@Override
public <T> T[] toArray(T[] array) {
  synchronized (lock) {
    return super.toArray(array);
  }
}

@Override
public boolean addAllUnique(Object[] objects, int start, int end) {
  synchronized (lock) {
    return super.addAllUnique(objects, start, end);
  }
}

@Override
public NotificationChain basicAdd(Resource object, NotificationChain notifications) {
  synchronized (lock) {
    return super.basicAdd(object, notifications);
  }
}

@Override
public void clear() {
  synchronized (lock) {
    super.clear();
  }
}

@Override
public boolean contains(Object object) {
  synchronized (lock) {
    return super.contains(object);
  }
}

public IResourceDescription getResourceDescription(Resource resource) {
  IResourceServiceProvider resourceServiceProvider = resourceServiceProviderRegistry.getResourceServiceProvider(resource.getURI());
  if (resourceServiceProvider == null)
    return null;
  IResourceDescription.Manager manager = resourceServiceProvider.getResourceDescriptionManager();
  if (manager == null)
    return null;
  IResourceDescription description = manager.getResourceDescription(resource);
  return description;
}

protected void initiallyProcessResource(XtextResource resource) {
  IResourceServiceProvider serviceProvider = resource.getResourceServiceProvider();
  if (serviceProvider != null) {
    IResourceDescription.Manager descriptionManager = serviceProvider.getResourceDescriptionManager();
    if (descriptionManager != null) {
      final IResourceDescription description = descriptionManager.getResourceDescription(resource);
      if (description != null)
        copyState(description);                            
    }
  }
}