LookaheadMatcher.java

/**
 * This file Copyright (c) 2005-2008 Aptana, Inc. This program is
 * dual-licensed under both the Aptana Public License and the GNU General
 * Public license. You may elect to use one or the other of these licenses.
 * 
 * This program is distributed in the hope that it will be useful, but
 * AS-IS and WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, TITLE, or
 * NONINFRINGEMENT. Redistribution, except as permitted by whichever of
 * the GPL or APL you select, is prohibited.
 *
 * 1. For the GPL license (GPL), you can redistribute and/or modify this
 * program under the terms of the GNU General Public License,
 * Version 3, as published by the Free Software Foundation.  You should
 * have received a copy of the GNU General Public License, Version 3 along
 * with this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 * 
 * Aptana provides a special exception to allow redistribution of this file
 * with certain other free and open source software ("FOSS") code and certain additional terms
 * pursuant to Section 7 of the GPL. You may view the exception and these
 * terms on the web at http://www.aptana.com/legal/gpl/.
 * 
 * 2. For the Aptana Public License (APL), this program and the
 * accompanying materials are made available under the terms of the APL
 * v1.0 which accompanies this distribution, and is available at
 * http://www.aptana.com/legal/apl/.
 * 
 * You may view the GPL, Aptana's exception and additional terms, and the
 * APL in the file titled license.html at the root of the corresponding
 * plugin containing this source file.
 * 
 * Any modifications to this file must keep this entire header intact.
 */
package com.aptana.ide.lexer.matcher;

import com.aptana.ide.lexer.ITokenList;

/**
 * @author Kevin Lindsey
 *
 */
public class LookaheadMatcher extends AbstractTextMatcher
{
	private boolean _negate;
	
	/**
	 * LookaheadMatcher
	 */
	public LookaheadMatcher()
	{
	}
	
	/**
	 * @see com.aptana.ide.lexer.matcher.AbstractTextMatcher#addChildTypes()
	 */
	public void addChildTypes()
	{
		this.addChildType(ITextMatcher.class);
	}
	
	/**
	 * @see com.aptana.ide.lexer.matcher.model.MatcherElement#createChildrenTokens(com.aptana.ide.lexer.ITokenList)
	 */
	protected void createChildrenTokens(ITokenList tokenList)
	{
		// wrap multiple children in an <and> element
		this.wrapChildrenInAndElement();
		
		// process as usual
		super.createChildrenTokens(tokenList);
	}

	/**
	 * @see com.aptana.ide.lexer.matcher.AbstractTextMatcher#match(char[], int, int)
	 */
	public int match(char[] source, int offset, int eofset)
	{
		int result = -1;
		
		if (this.getChildCount() > 0)
		{
			ITextMatcher matcher = (ITextMatcher) this.getChild(0);
			boolean match = (matcher.match(source, offset, eofset) != -1);
			
			if (match != this._negate)
			{
				result = offset;
			}
		}
		else
		{
			if (this._negate)
			{
				result = offset;
			}
		}
		
		if (result != -1)
		{
			this.accept(source, offset, result, this.token);
		}
		
		return result;
	}

	/**
	 * getNegate
	 *
	 * @return boolean
	 */
	public boolean getNegate()
	{
		return this._negate;
	}

	/**
	 * setNegate
	 *
	 * @param negate
	 */
	public void setNegate(boolean negate)
	{
		this._negate = negate;
	}

	/**
	 * @see com.aptana.ide.lexer.matcher.AbstractTextMatcher#toString()
	 */
	public String toString()
	{
		StringBuffer result = new StringBuffer();
		
		result.append("(?"); //$NON-NLS-1$
		
		if (this._negate)
		{
			result.append("!"); //$NON-NLS-1$
		}
		
		result.append(">"); //$NON-NLS-1$
		
		if (this.getChildCount() > 0)
		{
			result.append(this.getChild(0));
		}
		
		result.append(")"); //$NON-NLS-1$
		
		return result.toString();
	}

	/**
	 * @see com.aptana.ide.lexer.matcher.AbstractTextMatcher#validateLocal()
	 */
	protected void validateLocal()
	{
		super.validateLocal();
		
		int count = this.getChildCount();
		
		if (count == 0)
		{
			this.getDocument().sendError(Messages.LookaheadMatcher_No_Children, this);
		}
		else if (count > 1)
		{
			this.getDocument().sendInfo(Messages.LookaheadMatcher_Wrapping_Children, this);
		}
	}
}