How to use org.eclipse.jdt.internal.ui.text.correction

@Override
public void selectionChanged(ICompletionProposal proposal, boolean smartToggle) {
  if (proposal instanceof IStatusLineProposal) {
    IStatusLineProposal statusLineProposal= (IStatusLineProposal)proposal;
    String message= statusLineProposal.getStatusMessage();
    if (message != null) {
      fAssistant.setStatusMessage(message);
      return;
    }
  }
  fAssistant.setStatusMessage(getJumpHintStatusLineMessage());
}

public static IStatus collectAssists(IInvocationContext context, IProblemLocation[] locations, Collection<IJavaCompletionProposal> proposals) {
  ContributedProcessorDescriptor[] processors= getAssistProcessors();
  SafeAssistCollector collector= new SafeAssistCollector(context, locations, proposals);
  collector.process(processors);
  return collector.getStatus();
}

@Override
public void assistSessionStarted(ContentAssistEvent event) {
  fAssistant.setStatusLineVisible(true);
  fAssistant.setStatusMessage(getJumpHintStatusLineMessage());
}

public static boolean hasCorrections(ICompilationUnit cu, int problemId, String markerType) {
  ContributedProcessorDescriptor[] processors= getCorrectionProcessors();
  SafeHasCorrections collector= new SafeHasCorrections(cu, problemId);
  for (int i= 0; i < processors.length; i++) {
    if (processors[i].canHandleMarkerType(markerType)) {
      collector.process(processors[i]);
      if (collector.hasCorrections()) {
        return true;
      }
    }
  }
  return false;
}

public static IStatus collectCorrections(IInvocationContext context, IProblemLocation[] locations, Collection proposals) {
  ContributedProcessorDescriptor[] processors= getCorrectionProcessors();
  SafeCorrectionCollector collector= new SafeCorrectionCollector(context, proposals);
  for (int i= 0; i < processors.length; i++) {
    ContributedProcessorDescriptor curr= processors[i];
    IProblemLocation[] handled= getHandledProblems(locations, curr);
    if (handled != null) {
      collector.setProblemLocations(handled);
      collector.process(curr);
    }
  }
  return collector.getStatus();
}

public static boolean hasAssists(IInvocationContext context) {
  ContributedProcessorDescriptor[] processors= getAssistProcessors();
  SafeHasAssist collector= new SafeHasAssist(context);
  for (int i= 0; i < processors.length; i++) {
    collector.process(processors[i]);
    if (collector.hasAssists()) {
      return true;
    }
  }
  return false;
}

private static boolean getConvertSwitchToIfProposals(IInvocationContext context, ASTNode covering, Collection<ICommandAccess> resultingCollections) {
  if (!(covering instanceof SwitchStatement)) {
    return false;
  }
  //  we could produce quick assist (if all 'case' statements end with 'break')
  if (resultingCollections == null) {
    return true;
  }
  if (!getConvertSwitchToIfProposals(context, covering, resultingCollections, false))
    return false;
  return getConvertSwitchToIfProposals(context, covering, resultingCollections, true);
}

public QuickAssistLightBulbUpdater(ITextEditor part, ITextViewer viewer) {
  fEditor= part;
  fViewer= viewer;
  fAnnotation= new AssistAnnotation();
  fIsAnnotationShown= false;
  fPropertyChangeListener= null;
}

private static boolean getConvertIfElseToSwitchProposals(IInvocationContext context, ASTNode coveringNode, ArrayList<ICommandAccess> resultingCollections) {
  if (!(coveringNode instanceof IfStatement)) {
    return false;
  }
  //  we could produce quick assist
  if (resultingCollections == null) {
    return true;
  }
  if(!getConvertIfElseToSwitchProposals(context, coveringNode, resultingCollections, true))
    return false;
  return getConvertIfElseToSwitchProposals(context, coveringNode, resultingCollections, false);
}

  private void importNodeTypes(ASTNode node, final CompilationUnitRewrite cuRewrite, final ImportRewriteContext context) {
    ASTResolving.visitAllBindings(node, new TypeBindingVisitor() {
      @Override
      public boolean visit(ITypeBinding nodeBinding) {
        importBinding(nodeBinding, cuRewrite, context);
        return false;
      }
    });
  }
}

/**
 * Gets the text change that is invoked when the change is applied.
 * 
 * @return returns the text change that is invoked when the change is applied.
 * @throws CoreException throws an exception if accessing the change failed
 */
public final TextChange getTextChange() throws CoreException {
  return (TextChange) getChange();
}

public static boolean hasCorrections(ICompilationUnit cu, int problemId, String markerType) {
  ContributedProcessorDescriptor[] processors= getCorrectionProcessors();
  SafeHasCorrections collector= new SafeHasCorrections(cu, problemId);
  for (int i= 0; i < processors.length; i++) {
    if (processors[i].canHandleMarkerType(markerType)) {
      collector.process(processors[i]);
      if (collector.hasCorrections()) {
        return true;
      }
    }
  }
  return false;
}

public static IStatus collectAssists(IInvocationContext context, IProblemLocation[] locations, Collection proposals) {
  ContributedProcessorDescriptor[] processors= getAssistProcessors();
  SafeAssistCollector collector= new SafeAssistCollector(context, locations, proposals);
  collector.process(processors);
  return collector.getStatus();
}

public static boolean hasAssists(IInvocationContext context) {
  ContributedProcessorDescriptor[] processors= getAssistProcessors();
  SafeHasAssist collector= new SafeHasAssist(context);
  for (int i= 0; i < processors.length; i++) {
    collector.process(processors[i]);
    if (collector.hasAssists()) {
      return true;
    }
  }
  return false;
}

@Override
public void selectionChanged(ICompletionProposal proposal, boolean smartToggle) {
  if (proposal instanceof IStatusLineProposal) {
    IStatusLineProposal statusLineProposal= (IStatusLineProposal)proposal;
    String message= statusLineProposal.getStatusMessage();
    if (message != null) {
      fAssistant.setStatusMessage(message);
      return;
    }
  }
  fAssistant.setStatusMessage(getJumpHintStatusLineMessage());
}

@Override
public void assistSessionStarted(ContentAssistEvent event) {
  fAssistant.setStatusLineVisible(true);
  fAssistant.setStatusMessage(getJumpHintStatusLineMessage());
}

private static boolean getConvertSwitchToIfProposals(IInvocationContext context, ASTNode covering, Collection<ICommandAccess> resultingCollections) {
  if (!(covering instanceof SwitchStatement)) {
    return false;
  }
  //  we could produce quick assist (if all 'case' statements end with 'break')
  if (resultingCollections == null) {
    return true;
  }
  if (!getConvertSwitchToIfProposals(context, covering, resultingCollections, false))
    return false;
  return getConvertSwitchToIfProposals(context, covering, resultingCollections, true);
}

public static boolean hasCorrections(ICompilationUnit cu, int problemId, String markerType) {
  ContributedProcessorDescriptor[] processors= getCorrectionProcessors();
  SafeHasCorrections collector= new SafeHasCorrections(cu, problemId);
  for (int i= 0; i < processors.length; i++) {
    if (processors[i].canHandleMarkerType(markerType)) {
      collector.process(processors[i]);
      if (collector.hasCorrections()) {
        return true;
      }
    }
  }
  return false;
}

public static IStatus collectAssists(IInvocationContext context, IProblemLocation[] locations, Collection<IJavaCompletionProposal> proposals) {
  ContributedProcessorDescriptor[] processors= getAssistProcessors();
  SafeAssistCollector collector= new SafeAssistCollector(context, locations, proposals);
  collector.process(processors);
  return collector.getStatus();
}

public static boolean hasAssists(IInvocationContext context) {
  ContributedProcessorDescriptor[] processors= getAssistProcessors();
  SafeHasAssist collector= new SafeHasAssist(context);
  for (int i= 0; i < processors.length; i++) {
    collector.process(processors[i]);
    if (collector.hasAssists()) {
      return true;
    }
  }
  return false;
}