Copyright (c) 2005 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation
/*******************************************************************************
 * Copyright (c) 2005 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.ltk.internal.core.refactoring;

import org.eclipse.jface.text.BadPositionCategoryException;
import org.eclipse.jface.text.DocumentEvent;
import org.eclipse.jface.text.IPositionUpdater;
import org.eclipse.jface.text.Position;

Copied from org.eclipse.jface.text /** Copied from org.eclipse.jface.text */
public final class NonDeletingPositionUpdater implements IPositionUpdater {

	
The position category. /** The position category. */
	private final String fCategory;

	
Creates a new updater for the given category.
Params:
category – the new category./**
	 * Creates a new updater for the given <code>category</code>.
	 *
	 * @param category the new category.
	 */
	public NonDeletingPositionUpdater(String category) {
		fCategory= category;
	}

	/*
	 * @see org.eclipse.jface.text.IPositionUpdater#update(org.eclipse.jface.text.DocumentEvent)
	 */
	@Override
	public void update(DocumentEvent event) {

		int eventOffset= event.getOffset();
		int eventOldEndOffset= eventOffset + event.getLength();
		int eventNewLength= event.getText() == null ? 0 : event.getText().length();
		int eventNewEndOffset= eventOffset + eventNewLength;
		int deltaLength= eventNewLength - event.getLength();

		try {
			Position[] positions= event.getDocument().getPositions(fCategory);

			for (int i= 0; i != positions.length; i++) {

				Position position= positions[i];

				if (position.isDeleted())
					continue;

				int offset= position.getOffset();
				int length= position.getLength();
				int end= offset + length;

				if (offset > eventOldEndOffset) {
					// position comes way after change - shift
					position.setOffset(offset + deltaLength);
				} else if (end < eventOffset) {
					// position comes way before change - leave alone
				} else if (offset <= eventOffset && end >= eventOldEndOffset) {
					// event completely internal to the position - adjust length
					position.setLength(length + deltaLength);
				} else if (offset < eventOffset) {
					// event extends over end of position - include the
					// replacement text into the position
					position.setLength(eventNewEndOffset - offset);
				} else if (end > eventOldEndOffset) {
					// event extends from before position into it - adjust
					// offset and length, including the replacement text into
					// the position
					position.setOffset(eventOffset);
					int deleted= eventOldEndOffset - offset;
					position.setLength(length - deleted + eventNewLength);
				} else {
					// event comprises the position - keep it at the same
					// position, but always inside the replacement text
					int newOffset= Math.min(offset, eventNewEndOffset);
					int newEndOffset= Math.min(end, eventNewEndOffset);
					position.setOffset(newOffset);
					position.setLength(newEndOffset - newOffset);
				}
			}
		} catch (BadPositionCategoryException e) {
			// ignore and return
		}
	}

	
Returns the position category.
Returns:
the position category/**
	 * Returns the position category.
	 *
	 * @return the position category
	 */
	public String getCategory() {
		return fCategory;
	}
}