ChangeCorrectionProposal.java

/*******************************************************************************
 * Copyright (c) 2000, 2014 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.ui.text.java.correction;

import org.eclipse.che.jdt.ui.CheActionAcces;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.NullProgressMonitor;
import org.eclipse.core.runtime.Status;
import org.eclipse.jdt.internal.ui.JavaPlugin;
import org.eclipse.jdt.internal.ui.JavaPluginImages;
import org.eclipse.jdt.ui.text.java.IJavaCompletionProposal;
import org.eclipse.jface.text.IDocument;
import org.eclipse.che.jface.text.contentassist.ICompletionProposalExtension5;
import org.eclipse.che.jface.text.contentassist.ICompletionProposalExtension6;
import org.eclipse.che.jface.text.contentassist.IContextInformation;
import org.eclipse.jface.viewers.StyledString;
import org.eclipse.ltk.core.refactoring.Change;
import org.eclipse.ltk.core.refactoring.NullChange;
import org.eclipse.ltk.core.refactoring.RefactoringStatus;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;


/**
 * Implementation of a Java completion proposal to be used for quick fix and quick assist proposals
 * that are based on a {@link Change}. The proposal offers additional proposal information (based on
 * the {@link Change}).
 * 
 * @since 3.8
 */
public class ChangeCorrectionProposal
		implements IJavaCompletionProposal, ICommandAccess, ICompletionProposalExtension5, ICompletionProposalExtension6, CheActionAcces{

	private static final NullChange COMPUTING_CHANGE= new NullChange("ChangeCorrectionProposal computing..."); //$NON-NLS-1$
	
	private Change fChange;
	private String fName;
	private int fRelevance;
	private Image  fImage;
	private String fCommandId;

	/**
	 * Constructs a change correction proposal.
	 *
	 * @param name the name that is displayed in the proposal selection dialog
	 * @param change the change that is executed when the proposal is applied or <code>null</code>
	 *            if the change will be created by implementors of {@link #createChange()}
	 * @param relevance the relevance of this proposal
	 * @param image the image that is displayed for this proposal or <code>null</code> if no image
	 *            is desired
	 */
	public ChangeCorrectionProposal(String name, Change change, int relevance, Image image) {
		if (name == null) {
			throw new IllegalArgumentException("Name must not be null"); //$NON-NLS-1$
		}
		fName = name;
		fChange = change;
		fRelevance = relevance;
		fImage = image;
		fCommandId = null;
	}

	/**
	 * Constructs a change correction proposal. Uses the default image for this proposal.
	 *
	 * @param name The name that is displayed in the proposal selection dialog.
	 * @param change The change that is executed when the proposal is applied or <code>null</code>
	 *            if the change will be created by implementors of {@link #createChange()}.
	 * @param relevance The relevance of this proposal.
	 */
	public ChangeCorrectionProposal(String name, Change change, int relevance) {
		this(name, change, relevance, JavaPluginImages.get(JavaPluginImages.IMG_CORRECTION_CHANGE));
	}

	/*
	 * @see ICompletionProposal#apply(IDocument)
	 */
	public void apply(IDocument document) {
		try {
			performChange(/*JavaPlugin.getActivePage().getActiveEditor(),*/ document);
		} catch (CoreException e) {
//			ExceptionHandler.handle(e, CorrectionMessages.ChangeCorrectionProposal_error_title,
//									CorrectionMessages.ChangeCorrectionProposal_error_message);
			JavaPlugin.log(e);
		}
	}

	/**
	 * Performs the change associated with this proposal.
	 * <p>
	 * Subclasses may extend, but must call the super implementation.
	 *
	 * @param activeEditor the editor currently active or <code>null</code> if no editor is active
	 * @param document the document of the editor currently active or <code>null</code> if no editor
	 *            is visible
	 * @throws CoreException when the invocation of the change failed
	 */
	protected void performChange(/*IEditorPart activeEditor,*/ IDocument document) throws CoreException {
//		StyledText disabledStyledText = null;
//		TraverseListener traverseBlocker = null;

		Change change = null;
//		IRewriteTarget rewriteTarget = null;
		try {
			change = getChange();
			if (change != null) {
//				if (document != null) {
//					LinkedModeModel.closeAllModels(document);
//				}
//				if (activeEditor != null) {
//					rewriteTarget = (IRewriteTarget)activeEditor.getAdapter(IRewriteTarget.class);
//					if (rewriteTarget != null) {
//						rewriteTarget.beginCompoundChange();
//					}
//					/*
//					 * Workaround for https://bugs.eclipse.org/bugs/show_bug.cgi?id=195834#c7 :
//					 * During change execution, an EventLoopProgressMonitor can process the event queue while the text
//					 * widget has focus. When that happens and the user e.g. pressed a key, the event is prematurely
//					 * delivered to the text widget and screws up the document. Change execution fails or performs
//					 * wrong changes.
//					 *
//					 * The fix is to temporarily disable the text widget.
//					 */
//					Object control= activeEditor.getAdapter(Control.class);
//					if (control instanceof StyledText) {
//						disabledStyledText= (StyledText) control;
//						if (disabledStyledText.getEditable()) {
//							disabledStyledText.setEditable(false);
//							traverseBlocker= new TraverseListener() {
//								public void keyTraversed(TraverseEvent e) {
//									e.doit= true;
//									e.detail= SWT.TRAVERSE_NONE;
//								}
//							};
//							disabledStyledText.addTraverseListener(traverseBlocker);
//						} else {
//							disabledStyledText= null;
//						}
//					}
//				}

				change.initializeValidationData(new NullProgressMonitor());
				RefactoringStatus valid= change.isValid(new NullProgressMonitor());
				if (valid.hasFatalError()) {
					IStatus status= new Status(IStatus.ERROR, JavaPlugin.getPluginId(), IStatus.ERROR,
						valid.getMessageMatchingSeverity(RefactoringStatus.FATAL), null);
					throw new CoreException(status);
				} else {
//					IUndoManager manager= RefactoringCore.getUndoManager();
					Change undoChange;
					boolean successful= false;
					try {
//						manager.aboutToPerformChange(change);
						undoChange= change.perform(new NullProgressMonitor());
						successful= true;
					} finally {
//						manager.changePerformed(change, successful);
					}
					if (undoChange != null) {
//						undoChange.initializeValidationData(new NullProgressMonitor());
//						manager.addUndo(getName(), undoChange);
					}
				}
			}
		} finally {
//			if (disabledStyledText != null) {
//				disabledStyledText.setEditable(true);
//				disabledStyledText.removeTraverseListener(traverseBlocker);
//				// Workaround to fix bug 434791 during 4.4 RC2. Will be replaced by official API during 4.5.
//				ITextOperationTarget textOperationTarget= (ITextOperationTarget) activeEditor.getAdapter(ITextOperationTarget.class);
//				if (textOperationTarget != null && textOperationTarget.canDoOperation(-100))
//					textOperationTarget.doOperation(-100);
//			}
//			if (rewriteTarget != null) {
//				rewriteTarget.endCompoundChange();
//			}

			if (change != null) {
				change.dispose();
			}
		}
	}

	/*
	 * @see ICompletionProposal#getAdditionalProposalInfo()
	 */
	public String getAdditionalProposalInfo() {
		Object info= getAdditionalProposalInfo(new NullProgressMonitor());
		return info == null ? null : info.toString();
	}

	/*
	 * @see org.eclipse.jface.text.contentassist.ICompletionProposalExtension5#getAdditionalProposalInfo(org.eclipse.core.runtime.IProgressMonitor)
	 */
	public Object getAdditionalProposalInfo(IProgressMonitor monitor) {
		StringBuffer buf= new StringBuffer();
		buf.append("<p>"); //$NON-NLS-1$
		try {
			Change change= getChange();
			if (change != null) {
				String name= change.getName();
				if (name.length() == 0) {
					return null;
				}
				buf.append(name);
			} else {
				return null;
			}
		} catch (CoreException e) {
			buf.append("Unexpected error when accessing this proposal:<p><pre>"); //$NON-NLS-1$
			buf.append(e.getLocalizedMessage());
			buf.append("</pre>"); //$NON-NLS-1$
		}
		buf.append("</p>"); //$NON-NLS-1$
		return buf.toString();
	}

	/*
	 * @see ICompletionProposal#getContextInformation()
	 */
	public IContextInformation getContextInformation() {
		return null;
	}

	/*
	 * @see ICompletionProposal#getDisplayString()
	 */
	public String getDisplayString() {
//		String shortCutString= CorrectionCommandHandler.getShortCutString(getCommandId());
//		if (shortCutString != null) {
//			return Messages.format(CorrectionMessages.ChangeCorrectionProposal_name_with_shortcut, new String[]{getName(), shortCutString});
//		}
		return getName();
	}

	/* (non-Javadoc)
	 * @see org.eclipse.jface.text.contentassist.ICompletionProposalExtension6#getStyledDisplayString()
	 */
	public StyledString getStyledDisplayString() {
		StyledString str= new StyledString(getName());

//		String shortCutString= CorrectionCommandHandler.getShortCutString(getCommandId());
//		if (shortCutString != null) {
//			String decorated= Messages
//					.format(CorrectionMessages.ChangeCorrectionProposal_name_with_shortcut, new String[]{getName(), shortCutString});
//			return StyledCellLabelProvider.styleDecoratedString(decorated, StyledString.QUALIFIER_STYLER, str);
//		}
		return str;
	}

	/**
	 * Returns the name of the proposal.
	 *
	 * @return the name of the proposal
	 */
	public String getName() {
		return fName;
	}

	/*
	 * @see ICompletionProposal#getImage()
	 */
	public Image getImage() {
		return fImage;
	}

	/*
	 * @see ICompletionProposal#getSelection(IDocument)
	 */
	public Point getSelection(IDocument document) {
		return null;
	}

	/**
	 * Sets the proposal's image or <code>null</code> if no image is desired.
	 *
	 * @param image the desired image.
	 */
	public void setImage(Image image) {
		fImage= image;
	}

	/**
	 * Returns the change that will be executed when the proposal is applied.
	 * This method calls {@link #createChange()} to compute the change.
	 * 
	 * @return the change for this proposal, can be <code>null</code> in rare cases if creation of
	 *         the change failed
	 * @throws CoreException when the change could not be created
	 */
	public final Change getChange() throws CoreException {
//		if (Util.isGtk()) {
//			// workaround for https://bugs.eclipse.org/bugs/show_bug.cgi?id=293995 :
//			// [Widgets] Deadlock while UI thread displaying/computing a change proposal and non-UI thread creating image
//
//			// Solution is to create the change outside a 'synchronized' block.
//			// Synchronization is achieved by polling fChange, using "fChange == COMPUTING_CHANGE" as barrier.
//			// Timeout of 10s for safety reasons (should not be reached).
//			long end= System.currentTimeMillis() + 10000;
//			do {
//				boolean computing;
//				synchronized (this) {
//					computing= fChange == COMPUTING_CHANGE;
//				}
//				if (computing) {
//					try {
//						Display display= Display.getCurrent();
//						if (display != null) {
//							while (! display.isDisposed() && display.readAndDispatch()) {
//								// empty the display loop
//							}
//							display.sleep();
//						} else {
//							Thread.sleep(100);
//						}
//					} catch (InterruptedException e) {
//						//continue
//					}
//				} else {
//					synchronized (this) {
//						if (fChange == COMPUTING_CHANGE) {
//							continue;
//						} else if (fChange != null) {
//							return fChange;
//						} else {
//							fChange= COMPUTING_CHANGE;
//						}
//					}
//					Change change= createChange();
//					synchronized (this) {
//						fChange= change;
//					}
//					return change;
//				}
//			} while (System.currentTimeMillis() < end);
//
//			synchronized (this) {
//				if (fChange == COMPUTING_CHANGE) {
//					return null; //failed
//				}
//			}
//
//		} else {
			synchronized (this) {
				if (fChange == null) {
					fChange= createChange();
				}
			}
//		}
		return fChange;
	}

	/**
	 * Creates the change for this proposal.
	 * This method is only called once and only when no change has been passed in
 	 * {@link #ChangeCorrectionProposal(String, Change, int, Image)}.
 	 *
 	 * Subclasses may override.
 	 * 
	 * @return the created change
	 * @throws CoreException if the creation of the change failed
	 */
	protected Change createChange() throws CoreException {
		return new NullChange();
	}

	/**
	 * Sets the display name.
	 *
	 * @param name the name to set
	 */
	public void setDisplayName(String name) {
		if (name == null) {
			throw new IllegalArgumentException("Name must not be null"); //$NON-NLS-1$
		}
		fName= name;
	}

	/* (non-Javadoc)
	 * @see org.eclipse.jdt.ui.text.java.IJavaCompletionProposal#getRelevance()
	 */
	public int getRelevance() {
		return fRelevance;
	}

	/**
	 * Sets the relevance.
	 * 
	 * @param relevance the relevance to set
	 * 
	 * @see #getRelevance()
	 */
	public void setRelevance(int relevance) {
		fRelevance= relevance;
	}

	/* (non-Javadoc)
	 * @see org.eclipse.jdt.ui.text.java.correction.ICommandAccess#getCommandId()


	 */
	public String getCommandId() {
		return fCommandId;
	}

	/**
	 * Set the proposal id to allow assigning a shortcut to the correction proposal.
	 *
	 * @param commandId The proposal id for this proposal or <code>null</code> if no command
	 * should be assigned to this proposal.
	 */
	public void setCommandId(String commandId) {
		fCommandId= commandId;
	}

	@Override
	public String getActionId() {
		return null;
	}
}