wildcardmatcher.java

Mandarax是一个规则引擎的纯Java实现。它支持多类型的事实和基于反映的规则

package org.mandarax.util.regex;

/*
 * Copyright (C) 1999-2004 <A href="http://www-ist.massey.ac.nz/JBDietrich" target="_top">Jens Dietrich</a>
 *
 * This library 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 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.regex.*;


/**
 * An utility to match string containing wild cards.
 * @author <A href="http://www-ist.massey.ac.nz/JBDietrich" target="_top">Jens Dietrich</A>
 * @version 3.4 <7 March 05>
 * @since 3.0
 */

public class WildcardMatcher {
	private char SOME = '%';
	private char ONE = '_';
	private char ESC = '\\';
	
	public static final WildcardMatcher DB_INSTANCE = new WildcardMatcher('%','_','\\');
	public static final WildcardMatcher FILE_INSTANCE = new WildcardMatcher('*','?','\\');
	/**
	 * Constructor.
	 * @param some the character representing a sequence of characters
	 * @param one the character representing one character
	 * @param esc the character used to unmark special characters
	 */
	public WildcardMatcher(char some,char one,char esc) {
		super();
		SOME = some;
		ONE = one;
		ESC = esc;
	}
	
	/**
	 * Matches a string and a pattern containing wildcards.
	 * @param pattern a pattern string
	 * @param string the string to be tested
	 * @return a boolean
	 */
	public boolean matches(String pattern,String string) {
		if (string==null || pattern==null) return true;
		Pattern p = getPattern(pattern);
		Matcher m = p.matcher(string);
		return m.matches();
	}
	/**
	 * Get the RegEx pattern for the respective string with wild cards.
	 * @param pattern a pattern string
	 * @return a RegEx pattern instance
	 */
	public Pattern getPattern(String pattern) {
		String regExDef = replace(pattern,SOME,".*");
		regExDef = replace(regExDef,ONE,".");
		return Pattern.compile(regExDef);
	}
	
	
	/**
	 * Utility to replace sub strings by patterns.
	 * @param text a string
	 * @param old the old text
	 * @param replacement the text replacing the old text
	 * @return the result of the replacement
	 */
	public String replace(String text,char old,String replacement) {
		StringBuffer buf = new StringBuffer();
		for (int i=0;i<text.length();i++) {
			char c = text.charAt(i);
			if (c==old) {
				if (i>0 && buf.charAt(i-1)==ESC) buf.append(c);
				else buf.append(replacement);
			}
			else buf.append(c);
		}
		return buf.toString();
	}
}