package net.sourceforge.sqlexplorer.sqleditor;

/*
 * Copyright (C) 2002-2004 Andrea Mazzolini
 * andreamazzolini@users.sourceforge.net
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */


import java.util.ArrayList;
import java.util.List;

import net.sourceforge.sqlexplorer.IConstants;

import org.eclipse.jface.text.rules.EndOfLineRule;
import org.eclipse.jface.text.rules.IPredicateRule;
import org.eclipse.jface.text.rules.IToken;
import org.eclipse.jface.text.rules.IWordDetector;
import org.eclipse.jface.text.rules.MultiLineRule;
import org.eclipse.jface.text.rules.RuleBasedPartitionScanner;
import org.eclipse.jface.text.rules.SingleLineRule;
import org.eclipse.jface.text.rules.Token;
import org.eclipse.jface.text.rules.WordRule;

public class SQLPartitionScanner extends RuleBasedPartitionScanner {

	//private final static String SKIP= "__skip"; //$NON-NLS-1$


	/**
	 * Detector for empty comments.
	 */
	static class EmptyCommentDetector implements IWordDetector {

		public boolean isWordStart(char c) {
			return (c == '/');
		}

		public boolean isWordPart(char c) {
			return (c == '*' || c == '/');
		}
	};
	
		static class EmptyCommentRule extends WordRule implements IPredicateRule {
		
		private IToken fSuccessToken;
		/**
		 * Constructor for EmptyCommentRule.
		 * @param defaultToken
		 */
		public EmptyCommentRule(IToken successToken) {
			super(new EmptyCommentDetector());
			fSuccessToken= successToken;
			addWord("/**/", fSuccessToken); //$NON-NLS-1$
		}
		
		/*
		 * @see IPredicateRule#evaluate(ICharacterScanner, boolean)
		 */
		public IToken evaluate(org.eclipse.jface.text.rules.ICharacterScanner scanner, boolean resume) {
			return evaluate(scanner);
		}

		/*
		 * @see IPredicateRule#getSuccessToken()
		 */
		public IToken getSuccessToken() {
			return fSuccessToken;
		}
	};



	/**
	 * Creates the partitioner and sets up the appropriate rules.
	 */
	public SQLPartitionScanner() {
		super();

		//IToken skip= new Token(SKIP);
		IToken string= new Token(IConstants.SQL_STRING);
		IToken multiLineComment= new Token(IConstants.SQL_MULTILINE_COMMENT);
		IToken singleLineComment= new Token(IConstants.SQL_SINGLE_LINE_COMMENT);

		List rules= new ArrayList();

		// Add rule for single line comments.
		rules.add(new EndOfLineRule("--", singleLineComment)); //$NON-NLS-1$

		// Add rule for strings.		
		rules.add(new SingleLineRule("'", "'", string)); //$NON-NLS-2$ //$NON-NLS-1$
		
		// Add special case word rule.
		EmptyCommentRule wordRule= new EmptyCommentRule(multiLineComment);
		rules.add(wordRule);

		// Add rules for multi-line comments and javadoc.
		rules.add(new MultiLineRule("/*", "*/", multiLineComment)); //$NON-NLS-1$ //$NON-NLS-2$

		IPredicateRule[] result= new IPredicateRule[rules.size()];
		rules.toArray(result);
		setPredicateRules(result);

	}
}