org.eclipse.jface.text.DocumentEvent#getLength ( )源码实例Demo

@Override
public boolean validate(IDocument document, int offset, DocumentEvent event) {
	if (event != null) {
		int oldReplaceContextLength = getReplaceContextLength();
		int diff = event.getText().length() - event.getLength();
		setReplaceContextLength(oldReplaceContextLength + diff);
	}
	try {
		String prefix = document.get(replacementOffset, offset - replacementOffset);
		return matcher.isCandidateMatchingPrefix(replacementString, prefix);
	}
	catch (BadLocationException e) {
		log.info(e.getMessage(), e);
		return false;
	}
}
 

/**
 * Update the given position with the given event. The event overlaps with the start of the position.
 * 
 * @param position
 *            The position
 * @param event
 *            The event
 */
private void updateWithOverStartEvent(AttributedPosition position, DocumentEvent event) {
	int eventOffset = event.getOffset();
	int eventEnd = eventOffset + event.getLength();

	String newText = event.getText();
	if (newText == null)
		newText = ""; //$NON-NLS-1$
	int eventNewLength = newText.length();

	int excludedLength = eventNewLength;
	while (excludedLength > 0 && Character.isJavaIdentifierPart(newText.charAt(excludedLength - 1)))
		excludedLength--;
	int deleted = eventEnd - position.getOffset();
	int inserted = eventNewLength - excludedLength;
	position.update(eventOffset + excludedLength, position.getLength() - deleted + inserted);
}
 

public IRegion getDamageRegion(ITypedRegion partition, DocumentEvent event, boolean documentPartitioningChanged) {
    if (!documentPartitioningChanged) {
        try {

            IRegion info= document.getLineInformationOfOffset(event.getOffset());
            int start= Math.max(partition.getOffset(), info.getOffset());

            int end= event.getOffset() + (event.getText() == null ? event.getLength() : event.getText().length());

            if (info.getOffset() <= end && end <= info.getOffset() + info.getLength()) {
                // optimize the case of the same line
                end= info.getOffset() + info.getLength();
            } else
                end= endOfLineOf(end);

            end= Math.min(partition.getOffset() + partition.getLength(), end);
            return new Region(start, end - start);

        } catch (BadLocationException x) {
            logger.logInfo("unable to find location in document to repair a given region",x); //$NON-NLS-1$
        }
    }
    return partition;
}
 

/**
 * Update the given position with the given event. The event overlaps with the start of the position.
 *
 * @param position The position
 * @param event The event
 */
private void updateWithOverStartEvent(HighlightedPosition position, DocumentEvent event) {
	int eventOffset= event.getOffset();
	int eventEnd= eventOffset + event.getLength();

	String newText= event.getText();
	if (newText == null)
		newText= ""; //$NON-NLS-1$
	int eventNewLength= newText.length();

	int excludedLength= eventNewLength;
	while (excludedLength > 0 && Character.isJavaIdentifierPart(newText.charAt(excludedLength - 1)))
		excludedLength--;
	int deleted= eventEnd - position.getOffset();
	int inserted= eventNewLength - excludedLength;
	position.update(eventOffset + excludedLength, position.getLength() - deleted + inserted);
}
 

/**
 * Computes the change abstraction given a text event.
 *
 * @param event the text event to analyze
 * @return a change object describing the event
 */
private Change computeChange(TextEvent event) {
	DocumentEvent e= event.getDocumentEvent();
	if (e == null)
		return new Change(TypingRun.NO_CHANGE, -1);

	int start= e.getOffset();
	int end= e.getOffset() + e.getLength();
	String newText= e.getText();
	if (newText == null)
		newText= new String();

	if (start == end) {
		// no replace / delete / overwrite
		if (newText.length() == 1)
			return new Change(TypingRun.INSERT, end + 1);
	} else if (start == end - 1) {
		if (newText.length() == 1)
			return new Change(TypingRun.OVERTYPE, end);
		if (newText.length() == 0)
			return new Change(TypingRun.DELETE, start);
	}

	return new Change(TypingRun.UNKNOWN, -1);
}
 

/**
 * Determine if a selection is being replaced by non-emacs+ behavior (or YANK), and save the
 * replaced content in the kill ring. This captures the Eclipse (but not emacs) behavior where
 * typing/pasting into a selection replaces the old with the new, so it is appropriate to save
 * the old text to the kill ring.
 * 
 * @param event the DocumentEvent containing the IDocument, offset, and length
 * @return true if the non-zero length region matches the current selection in the editor
 */
private boolean isSelectionReplace(DocumentEvent event) {
	int len = event.getLength();
	// ignore plain insertion or any emacs+ (except YANK) command invocation
	if (selectionReplace &&  len > 0 && shouldSave()) {
		ITextEditor editor = EmacsPlusUtils.getCurrentEditor();
		// otherwise, if we can get the selection, see if it matches the replace region
		if (editor != null && editor.getDocumentProvider().getDocument(editor.getEditorInput()) == event.getDocument()) {
			ISelection isel = editor.getSelectionProvider().getSelection();
			if (isel instanceof ITextSelection) {
				ITextSelection selection = (ITextSelection)isel;
				boolean result = selection.getOffset() == event.getOffset() && selection.getLength() == len;
				return result;
			}
		}
	}
	return false;
}
 

@Override
public void documentChanged(DocumentEvent event) {

	String command = "document.replace(" + event.getOffset() + ", " + event.getLength() + ", \""
			+ toText(event.getText()) + "\");";
	write("\t\t" + command, true);

	//commands.add(new Command(command));
}
 

/**
 * @see IPresentationDamager#getDamageRegion(ITypedRegion, DocumentEvent, boolean)
 */
public IRegion getDamageRegion(
	ITypedRegion partition,
	DocumentEvent event,
	boolean documentPartitioningChanged) {
	if (!documentPartitioningChanged) {
		try {

			IRegion info =
				fDocument.getLineInformationOfOffset(event.getOffset());
			int start = Math.max(partition.getOffset(), info.getOffset());

			int end =
				event.getOffset()
					+ (event.getText() == null
						? event.getLength()
						: event.getText().length());

			if (info.getOffset() <= end
				&& end <= info.getOffset() + info.getLength()) {
				// optimize the case of the same line
				end = info.getOffset() + info.getLength();
			} else
				end = endOfLineOf(end);

			end =
				Math.min(
					partition.getOffset() + partition.getLength(),
					end);
			return new Region(start, end - start);

		} catch (BadLocationException x) {
		}
	}

	return partition;
}
 

/**
 * @see IPresentationDamager#getDamageRegion(ITypedRegion, DocumentEvent, boolean)
 */
public IRegion getDamageRegion(ITypedRegion partition, DocumentEvent event, boolean documentPartitioningChanged)
{
	if (!documentPartitioningChanged)
	{
		try
		{

			IRegion info = fDocument.getLineInformationOfOffset(event.getOffset());
			int start = Math.max(partition.getOffset(), info.getOffset());

			int end = event.getOffset()
					+ ((event.getText() == null) ? event.getLength() : event.getText().length());

			if (info.getOffset() <= end && end <= info.getOffset() + info.getLength())
			{
				// optimize the case of the same line
				end = info.getOffset() + info.getLength();
			}
			else
			{
				end = endOfLineOf(end);
			}
			end = Math.min(partition.getOffset() + partition.getLength(), end);
			return new Region(start, end - start);

		}
		catch (BadLocationException x)
		{
		}
	}

	return partition;
}
 

/**
 * Update the given position with the given event. The event precedes the position.
 *
 * @param position The position
 * @param event The event
 */
private void updateWithPrecedingEvent(HighlightedPosition position, DocumentEvent event) {
	String newText= event.getText();
	int eventNewLength= newText != null ? newText.length() : 0;
	int deltaLength= eventNewLength - event.getLength();

	position.setOffset(position.getOffset() + deltaLength);
}
 

@Override
public IRegion getDamageRegion(
	ITypedRegion partition,
	DocumentEvent event,
	boolean documentPartitioningChanged) {
	if (!documentPartitioningChanged) {
		try {

			IRegion info = fDocument.getLineInformationOfOffset(event.getOffset());
			int start = Math.max(partition.getOffset(), info.getOffset());

			int end =
				event.getOffset()
					+ (event.getText() == null
						? event.getLength()
						: event.getText().length());

			if (info.getOffset() <= end
				&& end <= info.getOffset() + info.getLength()) {
				// optimize the case of the same line
				end = info.getOffset() + info.getLength();
			} else
				end = endOfLineOf(end);

			end =
				Math.min(
					partition.getOffset() + partition.getLength(),
					end);
			return new Region(start, end - start);

		} catch (BadLocationException x) {
		}
	}

	return partition;
}
 

/**
 * @see IPresentationDamager#getDamageRegion(ITypedRegion, DocumentEvent,
 *      boolean)
 */
public IRegion getDamageRegion( ITypedRegion partition,
		DocumentEvent event, boolean documentPartitioningChanged )
{
	if ( !documentPartitioningChanged )
	{
		try
		{
			IRegion info = fDocument.getLineInformationOfOffset( event.getOffset( ) );
			int start = Math.max( partition.getOffset( ), info.getOffset( ) );

			int end = event.getOffset( )
					+ ( event.getText( ) == null ? event.getLength( )
							: event.getText( ).length( ) );

			if ( info.getOffset( ) <= end
					&& end <= info.getOffset( ) + info.getLength( ) )
			{
				// optimize the case of the same line
				end = info.getOffset( ) + info.getLength( );
			}
			else
			{
				end = endOfLineOf( end );
			}

			end = Math.min( partition.getOffset( ) + partition.getLength( ),
					end );

			return new Region( start, end - start );
		}
		catch ( BadLocationException x )
		{
		}
	}

	return partition;
}
 

/**
 * @see IPresentationDamager#getDamageRegion(ITypedRegion, DocumentEvent,
 *      boolean)
 */
public IRegion getDamageRegion( ITypedRegion partition,
		DocumentEvent event, boolean documentPartitioningChanged )
{
	if ( !documentPartitioningChanged )
	{
		try
		{

			IRegion info = fDocument.getLineInformationOfOffset( event.getOffset( ) );
			int start = Math.max( partition.getOffset( ), info.getOffset( ) );

			int end = event.getOffset( )
					+ ( event.getText( ) == null ? event.getLength( )
							: event.getText( ).length( ) );

			if ( info.getOffset( ) <= end
					&& end <= info.getOffset( ) + info.getLength( ) )
			{
				// optimize the case of the same line
				end = info.getOffset( ) + info.getLength( );
			}
			else
				end = endOfLineOf( end );

			end = Math.min( partition.getOffset( ) + partition.getLength( ),
					end );
			return new Region( start, end - start );

		}
		catch ( BadLocationException x )
		{
		}
	}

	return partition;
}
 

/**
 * @see IPresentationDamager#getDamageRegion(ITypedRegion, DocumentEvent,
 *      boolean)
 */
public IRegion getDamageRegion( ITypedRegion partition,
		DocumentEvent event, boolean documentPartitioningChanged )
{
	if ( !documentPartitioningChanged )
	{
		try
		{
			IRegion info = fDocument.getLineInformationOfOffset( event.getOffset( ) );
			int start = Math.max( partition.getOffset( ), info.getOffset( ) );

			int end = event.getOffset( )
					+ ( event.getText( ) == null ? event.getLength( )
							: event.getText( ).length( ) );

			if ( info.getOffset( ) <= end
					&& end <= info.getOffset( ) + info.getLength( ) )
			{
				// optimize the case of the same line
				end = info.getOffset( ) + info.getLength( );
			}
			else
			{
				end = endOfLineOf( end );
			}

			end = Math.min( partition.getOffset( ) + partition.getLength( ),
					end );

			return new Region( start, end - start );
		}
		catch ( BadLocationException x )
		{
		}
	}

	return partition;
}
 

/**
 * {@inheritDoc}
 * <p>
 * This implementation damages entire lines unless clipped by the given partition.
 * </p>
 *
 * @return the full lines containing the document changes described by the document event,
 *         clipped by the given partition. If there was a partitioning change then the whole
 *         partition is returned.
 */
@Override
public IRegion getDamageRegion(ITypedRegion partition, DocumentEvent e, boolean documentPartitioningChanged) {

    if (!documentPartitioningChanged) {
        try {

            IRegion info = fDocument.getLineInformationOfOffset(e.getOffset());
            int start = Math.max(partition.getOffset(), info.getOffset());

            int end = e.getOffset() + (e.getText() == null ? e.getLength() : e.getText().length());

            if (info.getOffset() <= end && end <= info.getOffset() + info.getLength()) {
                // optimize the case of the same line
                end = info.getOffset() + info.getLength();
            } else {
                end = endOfLineOf(end);
            }

            end = Math.min(partition.getOffset() + partition.getLength(), end);
            return new Region(start, end - start);

        } catch (BadLocationException x) {
        }
    }

    return partition;
}
 

/**
 * Gets the damage region.
 *
 * @param partition the partition
 * @param event the event
 * @param documentPartitioningChanged the document partitioning changed
 * @return the damage region
 * @see IPresentationDamager#getDamageRegion(ITypedRegion, DocumentEvent, boolean)
 */
@Override
public IRegion getDamageRegion(ITypedRegion partition, DocumentEvent event,
        boolean documentPartitioningChanged) {
  if (!documentPartitioningChanged) {
    try {

      IRegion info = fDocument.getLineInformationOfOffset(event.getOffset());
      int start = Math.max(partition.getOffset(), info.getOffset());

      int end = event.getOffset()
              + (event.getText() == null ? event.getLength() : event.getText().length());

      if (info.getOffset() <= end && end <= info.getOffset() + info.getLength()) {
        // optimize the case of the same line
        end = info.getOffset() + info.getLength();
      } else
        end = endOfLineOf(end);

      end = Math.min(partition.getOffset() + partition.getLength(), end);
      return new Region(start, end - start);

    } catch (BadLocationException x) {
    }
  }

  return partition;
}
 

public static int getEndLine(DocumentEvent event, boolean documentAboutToBeChanged) throws BadLocationException {
	int length = documentAboutToBeChanged ? event.getLength() : event.getText().length();
	return event.getDocument().getLineOfOffset(event.getOffset() + length);
}
 

public static boolean isInsert(DocumentEvent event) {
	return event.getLength() == 0 && event.getText() != null;
}
 

/**
 * Update the given position with the given event. The event precedes the position.
 * 
 * @param position
 *            The position
 * @param event
 *            The event
 */
private void updateWithPrecedingEvent(AttributedPosition position, DocumentEvent event) {
	String newText = event.getText();
	int eventNewLength = newText != null ? newText.length() : 0;
	int deltaLength = eventNewLength - event.getLength();

	position.setOffset(position.getOffset() + deltaLength);
}