/*

* Copyright (c) 2006 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the License "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description: 

*

*/

package com.nokia.sdt.sourcegen.patcher;

import java.util.regex.Pattern;

/**

 * This implements a subset of IPatchHandler which canonicalizes 

 * lines for comparison. 

 * 

 *

 */

public abstract class BaseSourceGenPatchHandler implements IPatchHandler {

	protected static Pattern WHITESPACE_REMOVAL = Pattern.compile("\\s+"); //$NON-NLS-1$

	/**

	 * Routine to get a line in the canonical format for determining

	 * if it is empty or can match another line in the same format.

	 * Override in subclasses if needed.

	 * @param line

	 * @return line with whitespace removed

	 */

	protected String removeAllWhitespace(String line) {

		return WHITESPACE_REMOVAL.matcher(line).replaceAll(""); //$NON-NLS-1$  

	}

	/* (non-Javadoc)

	 * @see com.nokia.sdt.sourcegen.patcher.IPatchHandler#isLineEmpty(java.lang.String)

	 */

	final public boolean isLineEmpty(String srcLine) {

		return removeAllWhitespace(srcLine).length() == 0;

	}

	/* (non-Javadoc)

	 * @see com.nokia.sdt.sourcegen.patcher.IPatchHandler#matchLines(java.lang.String, java.lang.String)

	 */

	final public boolean matchLines(String from, String to) {

		// we match with no whitespace comparison

		String from0 = removeAllWhitespace(from); //$NON-NLS-1$  

		String to0 = removeAllWhitespace(to); //$NON-NLS-1$  

		if (from0.length() > 0 && to0.length() > 0) {

			return from0.equals(to0);

		} else {

			// must be comments, so just delete surrounding whitespace

			return from.trim().equals(to.trim());

		}

	}

}