query/plugins/org.eclipse.acceleo.query.ide.ui/src/org/eclipse/acceleo/query/ide/ui/viewer/AQLDoubleClickStrategy.java

/*******************************************************************************
 * Copyright (c) 2017 Obeo.
 * 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:
 *     Obeo - initial API and implementation
 *******************************************************************************/
package org.eclipse.acceleo.query.ide.ui.viewer;

import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.ITextDoubleClickStrategy;
import org.eclipse.jface.text.ITextViewer;

/**
 * AQL {@link ITextDoubleClickStrategy}.
 * 
 * @author <a href="mailto:yvan.lussaud@obeo.fr">Yvan Lussaud</a>
 */
public class AQLDoubleClickStrategy implements ITextDoubleClickStrategy {

	/**
	 * {@inheritDoc}
	 *
	 * @see org.eclipse.jface.text.ITextDoubleClickStrategy#doubleClicked(org.eclipse.jface.text.ITextViewer)
	 */
	public void doubleClicked(ITextViewer part) {
		final int pos = part.getSelectedRange().x;
		if (pos >= 0) {
			selectWord(part, pos);
		}
	}

	/**
	 * Selects a word in the given {@link ITextViewer} at the given caret position.
	 * 
	 * @param text
	 *            the {@link ITextViewer}
	 * @param caretPos
	 *            the caret position
	 * @return <code>true</code> if the selection has been made, <code>false</code> otherwise
	 */
	protected boolean selectWord(ITextViewer text, int caretPos) {
		boolean res;

		IDocument doc = text.getDocument();
		int startPos;
		int endPos;

		try {
			int pos = caretPos;
			char c;

			while (pos >= 0) {
				c = doc.getChar(pos);
				if (!Character.isJavaIdentifierPart(c)) {
					break;
				}
				pos--;
			}

			startPos = pos;

			pos = caretPos;
			int length = doc.getLength();

			while (pos < length) {
				c = doc.getChar(pos);
				if (!Character.isJavaIdentifierPart(c)) {
					break;
				}
				pos++;
			}

			endPos = pos;
			selectRange(text, startPos, endPos);
			res = true;

		} catch (BadLocationException x) {
			res = false;
		}

		return res;
	}

	/**
	 * Selects the given range.
	 * 
	 * @param text
	 *            the {@link ITextViewer}
	 * @param start
	 *            the start position
	 * @param stop
	 *            the end position
	 */
	private void selectRange(ITextViewer text, int start, int stop) {
		int offset = start + 1;
		int length = stop - offset;
		text.setSelectedRange(offset, length);
	}
}