gt: 					if (res == null) {
context: /*******************************************************************************
   * Copyright (c) 2000, 2012 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 API and implementation
   *******************************************************************************/
  
  package org.eclipse.jdt.internal.ui.text.correction;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collection;
  
  import org.eclipse.core.runtime.IConfigurationElement;
  import org.eclipse.core.runtime.ISafeRunnable;
  import org.eclipse.core.runtime.IStatus;
  import org.eclipse.core.runtime.MultiStatus;
  import org.eclipse.core.runtime.Platform;
  import org.eclipse.core.runtime.SafeRunner;
  import org.eclipse.core.runtime.Status;
  
  import org.eclipse.core.resources.IMarker;
  
  import org.eclipse.jface.text.Position;
  import org.eclipse.jface.text.contentassist.ContentAssistEvent;
  import org.eclipse.jface.text.contentassist.ICompletionListener;
  import org.eclipse.jface.text.contentassist.ICompletionProposal;
  import org.eclipse.jface.text.quickassist.IQuickAssistInvocationContext;
  import org.eclipse.jface.text.source.Annotation;
  import org.eclipse.jface.text.source.IAnnotationModel;
  import org.eclipse.jface.text.source.ISourceViewer;
  
  import org.eclipse.ui.IEditorPart;
  import org.eclipse.ui.IMarkerHelpRegistry;
  import org.eclipse.ui.IMarkerResolution;
  import org.eclipse.ui.PlatformUI;
  import org.eclipse.ui.ide.IDE;
  import org.eclipse.ui.keys.IBindingService;
  
  import org.eclipse.ui.texteditor.ITextEditorActionDefinitionIds;
  import org.eclipse.ui.texteditor.SimpleMarkerAnnotation;
  
  import org.eclipse.ltk.core.refactoring.NullChange;
  
  import org.eclipse.jdt.core.ICompilationUnit;
  
  import org.eclipse.jdt.internal.corext.util.Messages;
  
  import org.eclipse.jdt.ui.JavaUI;
  import org.eclipse.jdt.ui.text.java.CompletionProposalComparator;
  import org.eclipse.jdt.ui.text.java.IInvocationContext;
  import org.eclipse.jdt.ui.text.java.IJavaCompletionProposal;
  import org.eclipse.jdt.ui.text.java.IProblemLocation;
  import org.eclipse.jdt.ui.text.java.IQuickAssistProcessor;
  import org.eclipse.jdt.ui.text.java.IQuickFixProcessor;
  import org.eclipse.jdt.ui.text.java.correction.ChangeCorrectionProposal;
  
  import org.eclipse.jdt.internal.ui.JavaPlugin;
  import org.eclipse.jdt.internal.ui.javaeditor.IJavaAnnotation;
  import org.eclipse.jdt.internal.ui.text.correction.proposals.MarkerResolutionProposal;
  
  
  public class JavaCorrectionProcessor implements org.eclipse.jface.text.quickassist.IQuickAssistProcessor {
  
  	private static final String QUICKFIX_PROCESSOR_CONTRIBUTION_ID= "quickFixProcessors"; //$NON-NLS-1$
  	private static final String QUICKASSIST_PROCESSOR_CONTRIBUTION_ID= "quickAssistProcessors"; //$NON-NLS-1$
  
  	private static ContributedProcessorDescriptor[] fgContributedAssistProcessors= null;
  	private static ContributedProcessorDescriptor[] fgContributedCorrectionProcessors= null;
  
  	private static ContributedProcessorDescriptor[] getProcessorDescriptors(String contributionId, boolean testMarkerTypes) {
  		IConfigurationElement[] elements= Platform.getExtensionRegistry().getConfigurationElementsFor(JavaUI.ID_PLUGIN, contributionId);
  		ArrayList<ContributedProcessorDescriptor> res= new ArrayList<>(elements.length);
  
  		for (int i= 0; i < elements.length; i++) {
  			ContributedProcessorDescriptor desc= new ContributedProcessorDescriptor(elements[i], testMarkerTypes);
  			IStatus status= desc.checkSyntax();
  			if (status.isOK()) {
  				res.add(desc);
  			} else {
  				JavaPlugin.log(status);
  			}
  		}
  		return res.toArray(new ContributedProcessorDescriptor[res.size()]);
  	}
  
  	private static ContributedProcessorDescriptor[] getCorrectionProcessors() {
  		if (fgContributedCorrectionProcessors == null) {
  			fgContributedCorrectionProcessors= getProcessorDescriptors(QUICKFIX_PROCESSOR_CONTRIBUTION_ID, true);
  		}
  		return fgContributedCorrectionProcessors;
  	}
  
  	private static ContributedProcessorDescriptor[] getAssistProcessors() {
  		if (fgContributedAssistProcessors == null) {
  			fgContributedAssistProcessors= getProcessorDescriptors(QUICKASSIST_PROCESSOR_CONTRIBUTION_ID, false);
  		}
  		return fgContributedAssistProcessors;
  	}
  
  	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 boolean isQuickFixableType(Annotation annotation) {
  		return (annotation instanceof IJavaAnnotation || annotation instanceof SimpleMarkerAnnotation) && !annotation.isMarkedDeleted();
  	}
  
  
  	public static boolean hasCorrections(Annotation annotation) {
  		if (annotation instanceof IJavaAnnotation) {
  			IJavaAnnotation javaAnnotation= (IJavaAnnotation) annotation;
  			int problemId= javaAnnotation.getId();
  			if (problemId != -1) {
  				ICompilationUnit cu= javaAnnotation.getCompilationUnit();
  				if (cu != null) {
  					return hasCorrections(cu, problemId, javaAnnotation.getMarkerType());
  				}
  			}
  		}
  		if (annotation instanceof SimpleMarkerAnnotation) {
  			return hasCorrections(((SimpleMarkerAnnotation) annotation).getMarker());
  		}
  		return false;
  	}
  
  	private static boolean hasCorrections(IMarker marker) {
  		if (marker == null || !marker.exists())
  			return false;
  
  		IMarkerHelpRegistry registry= IDE.getMarkerHelpRegistry();
  		return registry != null && registry.hasResolutions(marker);
  	}
  
  	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 JavaCorrectionAssistant fAssistant;
  	private String fErrorMessage;
  
  	/*
  	 * Constructor for JavaCorrectionProcessor.
  	 */
  	public JavaCorrectionProcessor(JavaCorrectionAssistant assistant) {
  		fAssistant= assistant;
  		fAssistant.addCompletionListener(new ICompletionListener() {
  
  			@Override
  			public void assistSessionEnded(ContentAssistEvent event) {
  				fAssistant.setStatusLineVisible(false);
  			}
  
  			@Override
  			public void assistSessionStarted(ContentAssistEvent event) {
  				fAssistant.setStatusLineVisible(true);
  				fAssistant.setStatusMessage(getJumpHintStatusLineMessage());
  			}
  
  			@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());
  			}
  
  			private String getJumpHintStatusLineMessage() {
  				if (fAssistant.isUpdatedOffset()) {
  					String key= getQuickAssistBinding();
  					if (key == null)
  						return CorrectionMessages.JavaCorrectionProcessor_go_to_original_using_menu;
  					else
  						return Messages.format(CorrectionMessages.JavaCorrectionProcessor_go_to_original_using_key, key);
  				} else if (fAssistant.isProblemLocationAvailable()) {
  					String key= getQuickAssistBinding();
  					if (key == null)
  						return CorrectionMessages.JavaCorrectionProcessor_go_to_closest_using_menu;
  					else
  						return Messages.format(CorrectionMessages.JavaCorrectionProcessor_go_to_closest_using_key, key);
  				} else
  					return ""; //$NON-NLS-1$
  			}
  
  			private String getQuickAssistBinding() {
  				final IBindingService bindingSvc= PlatformUI.getWorkbench().getAdapter(IBindingService.class);
  				return bindingSvc.getBestActiveBindingFormattedFor(ITextEditorActionDefinitionIds.QUICK_ASSIST);
  			}
  		});
  	}
  
  	/*
  	 * @see IContentAssistProcessor#computeCompletionProposals(ITextViewer, int)
  	 */
  	@Override
  	public ICompletionProposal[] computeQuickAssistProposals(IQuickAssistInvocationContext quickAssistContext) {
  		ISourceViewer viewer= quickAssistContext.getSourceViewer();
  		int documentOffset= quickAssistContext.getOffset();
  
  		IEditorPart part= fAssistant.getEditor();
  
  		ICompilationUnit cu= JavaUI.getWorkingCopyManager().getWorkingCopy(part.getEditorInput());
  		IAnnotationModel model= JavaUI.getDocumentProvider().getAnnotationModel(part.getEditorInput());
  
  		AssistContext context= null;
  		if (cu != null) {
  			int length= viewer != null ? viewer.getSelectedRange().y : 0;
  			context= new AssistContext(cu, viewer, part, documentOffset, length);
  		}
  		
  		Annotation[] annotations= fAssistant.getAnnotationsAtOffset();
  
  		fErrorMessage= null;
  
  		ICompletionProposal[] res= null;
  		if (model != null && context != null && annotations != null) {
  			ArrayList<IJavaCompletionProposal> proposals= new ArrayList<>(10);
  			IStatus status= collectProposals(context, model, annotations, true, !fAssistant.isUpdatedOffset(), proposals);
  			res= proposals.toArray(new ICompletionProposal[proposals.size()]);
  			if (!status.isOK()) {
  				fErrorMessage= status.getMessage();
  				JavaPlugin.log(status);
  			}
  		}
  
  		if (res == null || res.length == 0) {
  			return new ICompletionProposal[] { new ChangeCorrectionProposal(CorrectionMessages.NoCorrectionProposal_description, new NullChange(""), IProposalRelevance.NO_SUGGESSTIONS_AVAILABLE, null) }; //$NON-NLS-1$
  		}
  		if (res.length > 1) {
  			Arrays.sort(res, new CompletionProposalComparator());
  		}
  		return res;
  	}
  
  	public static IStatus collectProposals(IInvocationContext context, IAnnotationModel model, Annotation[] annotations, boolean addQuickFixes, boolean addQuickAssists, Collection<IJavaCompletionProposal> proposals) {
  		ArrayList<ProblemLocation> problems= new ArrayList<>();
  
  		// collect problem locations and corrections from marker annotations
  		for (int i= 0; i < annotations.length; i++) {
  			Annotation curr= annotations[i];
  			ProblemLocation problemLocation= null;
  			if (curr instanceof IJavaAnnotation) {
  				problemLocation= getProblemLocation((IJavaAnnotation) curr, model);
  				if (problemLocation != null) {
  					problems.add(problemLocation);
  				}
  			}
  			if (problemLocation == null && addQuickFixes && curr instanceof SimpleMarkerAnnotation) {
  				collectMarkerProposals((SimpleMarkerAnnotation) curr, proposals);
  			}
  		}
  		MultiStatus resStatus= null;
  
  		IProblemLocation[] problemLocations= problems.toArray(new IProblemLocation[problems.size()]);
  		if (addQuickFixes) {
  			IStatus status= collectCorrections(context, problemLocations, proposals);
  			if (!status.isOK()) {
  				resStatus= new MultiStatus(JavaUI.ID_PLUGIN, IStatus.ERROR, CorrectionMessages.JavaCorrectionProcessor_error_quickfix_message, null);
  				resStatus.add(status);
  			}
  		}
  		if (addQuickAssists) {
  			IStatus status= collectAssists(context, problemLocations, proposals);
  			if (!status.isOK()) {
  				if (resStatus == null) {
  					resStatus= new MultiStatus(JavaUI.ID_PLUGIN, IStatus.ERROR, CorrectionMessages.JavaCorrectionProcessor_error_quickassist_message, null);
  				}
  				resStatus.add(status);
  			}
  		}
  		if (resStatus != null) {
  			return resStatus;
  		}
  		return Status.OK_STATUS;
  	}
  
  	private static ProblemLocation getProblemLocation(IJavaAnnotation javaAnnotation, IAnnotationModel model) {
  		int problemId= javaAnnotation.getId();
  		if (problemId != -1) {
  			Position pos= model.getPosition((Annotation) javaAnnotation);
  			if (pos != null) {
  				return new ProblemLocation(pos.getOffset(), pos.getLength(), javaAnnotation); // java problems all handled by the quick assist processors
  			}
  		}
  		return null;
  	}
  
  	private static void collectMarkerProposals(SimpleMarkerAnnotation annotation, Collection<IJavaCompletionProposal> proposals) {
  		IMarker marker= annotation.getMarker();
  		IMarkerResolution[] res= IDE.getMarkerHelpRegistry().getResolutions(marker);
  		if (res.length > 0) {
  			for (int i= 0; i < res.length; i++) {
  				proposals.add(new MarkerResolutionProposal(res[i], marker));
  			}
  		}
  	}
  
  	private static abstract class SafeCorrectionProcessorAccess implements ISafeRunnable {
  		private MultiStatus fMulti= null;
  		private ContributedProcessorDescriptor fDescriptor;
  
  		public void process(ContributedProcessorDescriptor[] desc) {
  			for (int i= 0; i < desc.length; i++) {
  				fDescriptor= desc[i];
  				SafeRunner.run(this);
  			}
  		}
  
  		public void process(ContributedProcessorDescriptor desc) {
  			fDescriptor= desc;
  			SafeRunner.run(this);
  		}
  
  		@Override
  		public void run() throws Exception {
  			safeRun(fDescriptor);
  		}
  
  		protected abstract void safeRun(ContributedProcessorDescriptor processor) throws Exception;
  
  		@Override
  		public void handleException(Throwable exception) {
  			if (fMulti == null) {
  				fMulti= new MultiStatus(JavaUI.ID_PLUGIN, IStatus.OK, CorrectionMessages.JavaCorrectionProcessor_error_status, null);
  			}
  			fMulti.merge(new Status(IStatus.ERROR, JavaUI.ID_PLUGIN, IStatus.ERROR, CorrectionMessages.JavaCorrectionProcessor_error_status, exception));
  		}
  
  		public IStatus getStatus() {
  			if (fMulti == null) {
  				return Status.OK_STATUS;
  			}
  			return fMulti;
  		}
  
  	}
  
  	private static class SafeCorrectionCollector extends SafeCorrectionProcessorAccess {
  		private final IInvocationContext fContext;
  		private final Collection<IJavaCompletionProposal> fProposals;
  		private IProblemLocation[] fLocations;
  
  		public SafeCorrectionCollector(IInvocationContext context, Collection<IJavaCompletionProposal> proposals) {
  			fContext= context;
  			fProposals= proposals;
  		}
  
  		public void setProblemLocations(IProblemLocation[] locations) {
  			fLocations= locations;
  		}
  
  		@Override
  		public void safeRun(ContributedProcessorDescriptor desc) throws Exception {
  			IQuickFixProcessor curr= (IQuickFixProcessor) desc.getProcessor(fContext.getCompilationUnit(), IQuickFixProcessor.class);
  			if (curr != null) {
  				IJavaCompletionProposal[] res= curr.getCorrections(fContext, fLocations);
  				if (res != null) {
  					for (int k= 0; k < res.length; k++) {
  						fProposals.add(res[k]);
  					}
  				}
  			}
  		}
  	}
  
  	private static class SafeAssistCollector extends SafeCorrectionProcessorAccess {
  		private final IInvocationContext fContext;
  		private final IProblemLocation[] fLocations;
  		private final Collection<IJavaCompletionProposal> fProposals;
  
  		public SafeAssistCollector(IInvocationContext context, IProblemLocation[] locations, Collection<IJavaCompletionProposal> proposals) {
  			fContext= context;
  			fLocations= locations;
  			fProposals= proposals;
  		}
  
  		@Override
  		public void safeRun(ContributedProcessorDescriptor desc) throws Exception {
  			IQuickAssistProcessor curr= (IQuickAssistProcessor) desc.getProcessor(fContext.getCompilationUnit(), IQuickAssistProcessor.class);
  			if (curr != null) {
  				IJavaCompletionProposal[] res= curr.getAssists(fContext, fLocations);
  				if (res != null) {
  					for (int k= 0; k < res.length; k++) {
  						fProposals.add(res[k]);
  					}
  				}
  			}
  		}
  	}
  
  	private static class SafeHasAssist extends SafeCorrectionProcessorAccess {
  		private final IInvocationContext fContext;
  		private boolean fHasAssists;
  
  		public SafeHasAssist(IInvocationContext context) {
  			fContext= context;
  			fHasAssists= false;
  		}
  
  		public boolean hasAssists() {
  			return fHasAssists;
  		}
  
  		@Override
  		public void safeRun(ContributedProcessorDescriptor desc) throws Exception {
  			IQuickAssistProcessor processor= (IQuickAssistProcessor) desc.getProcessor(fContext.getCompilationUnit(), IQuickAssistProcessor.class);
  			if (processor != null && processor.hasAssists(fContext)) {
  				fHasAssists= true;
  			}
  		}
  	}
  
  	private static class SafeHasCorrections extends SafeCorrectionProcessorAccess {
  		private final ICompilationUnit fCu;
  		private final int fProblemId;
  		private boolean fHasCorrections;
  
  		public SafeHasCorrections(ICompilationUnit cu, int problemId) {
  			fCu= cu;
  			fProblemId= problemId;
  			fHasCorrections= false;
  		}
  
  		public boolean hasCorrections() {
  			return fHasCorrections;
  		}
  
  		@Override
  		public void safeRun(ContributedProcessorDescriptor desc) throws Exception {
  			IQuickFixProcessor processor= (IQuickFixProcessor) desc.getProcessor(fCu, IQuickFixProcessor.class);
  			if (processor != null && processor.hasCorrections(fCu, fProblemId)) {
  				fHasCorrections= true;
  			}
  		}
  	}
  
  
  	public static IStatus collectCorrections(IInvocationContext context, IProblemLocation[] locations, Collection<IJavaCompletionProposal> 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();
  	}
  
  	private static IProblemLocation[] getHandledProblems(IProblemLocation[] locations, ContributedProcessorDescriptor processor) {
  		// implementation tries to avoid creating a new array
  		boolean allHandled= true;
  		ArrayList<IProblemLocation> res= null;
  		for (int i= 0; i < locations.length; i++) {
  			IProblemLocation curr= locations[i];
  			if (processor.canHandleMarkerType(curr.getMarkerType())) {
  				if (!allHandled) { // first handled problem
  