org.eclipse.jface.text.link.InclusivePositionUpdater Maven / Gradle / Ivy

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AspectJ tools most notably contains the AspectJ compiler (AJC). AJC applies aspects to Java classes during compilation, fully replacing Javac for plain Java classes and also compiling native AspectJ or annotation-based @AspectJ syntax. Furthermore, AJC can weave aspects into existing class files in a post-compile binary weaving step. This library is a superset of AspectJ weaver and hence also of AspectJ runtime.

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/*******************************************************************************
 * Copyright (c) 2000, 2008 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.jface.text.link;

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


/**
 * Position updater that considers any change in
 * [p.offset, p.offset + p.length] of a {@link Position}
 * p as belonging to the position.
 *
 * @since 3.0
 * @noextend This class is not intended to be subclassed by clients.
 */
public class InclusivePositionUpdater implements IPositionUpdater {

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

	/**
	 * Creates a new updater for the given category.
	 *
	 * @param category the new category.
	 */
	public InclusivePositionUpdater(String category) {
		fCategory= category;
	}

	@Override
	public void update(DocumentEvent event) {

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

		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 > eventOffset + eventOldLength)
					// 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 >= eventOffset + eventOldLength) {
					// event completely internal to the position - adjust length
					position.setLength(length + deltaLength);
				} else if (offset < eventOffset) {
					// event extends over end of position - adjust length
					int newEnd= eventOffset + eventNewLength;
					position.setLength(newEnd - offset);
				} else if (end > eventOffset + eventOldLength) {
					// event extends from before position into it - adjust offset
					// and length
					// offset becomes end of event, length adjusted accordingly
					// we want to recycle the overlapping part
					position.setOffset(eventOffset);
					int deleted= eventOffset + eventOldLength - offset;
					position.setLength(length - deleted + eventNewLength);
				} else {
					// event consumes the position - delete it
					position.delete();
				}
			}
		} catch (BadPositionCategoryException e) {
			// ignore and return
		}
	}

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

}