rdonkin 2003/04/02 11:04:42
Added: digester/src/java/org/apache/commons/digester
SimpleRegexMatcher.java
Log:
Added new Rule implementation based on a pluggable regex implementation. Also test
case and a simple regex matching implementation
Revision Changes Path
1.1
jakarta-commons/digester/src/java/org/apache/commons/digester/SimpleRegexMatcher.java
Index: SimpleRegexMatcher.java
===================================================================
/*
* $Header:
/home/cvs/jakarta-commons/digester/src/java/org/apache/commons/digester/SimpleRegexMatcher.java,v
1.1 2003/04/02 19:04:42 rdonkin Exp $
* $Revision: 1.1 $
* $Date: 2003/04/02 19:04:42 $
*
* ====================================================================
*
* The Apache Software License, Version 1.1
*
* Copyright (c) 1999-2003 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowlegement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The Jakarta Project", "Commons", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact [EMAIL PROTECTED]
*
* 5. Products derived from this software may not be called "Apache"
* nor may "Apache" appear in their names without prior written
* permission of the Apache Group.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/
package org.apache.commons.digester;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* <p>Simple regex pattern matching algorithm.</p>
*
* <p>This uses just two wildcards:
* <ul>
* <li><code>*</code> matches any sequence of none, one or more characters
* <li><code>?</code> matches any one character
* </ul>
* Escaping these wildcards is not supported .</p>
*
* @author Robert Burrell Donkin
* @version $Revision: 1.1 $ $Date: 2003/04/02 19:04:42 $
*/
public class SimpleRegexMatcher extends RegexMatcher {
// --------------------------------------------------------- Fields
/** Default log (class wide) */
private static final Log baseLog = LogFactory.getLog(SimpleRegexMatcher.class);
/** Custom log (can be set per object) */
private Log log = baseLog;
// --------------------------------------------------------- Properties
/**
* Gets the <code>Log</code> implementation.
*/
public Log getLog() {
return log;
}
/**
* Sets the current <code>Log</code> implementation used by this class.
*/
public void setLog(Log log) {
this.log = log;
}
// --------------------------------------------------------- Public Methods
/**
* Matches using simple regex algorithm.
*
*
* @param basePattern the standard digester path representing the element
* @param regexPattern the regex pattern the path will be tested against
* @return true if the given pattern matches the given path
*/
public boolean match(String basePattern, String regexPattern) {
// check for nulls
if (basePattern == null || regexPattern == null) {
return false;
}
return match(basePattern, regexPattern, 0, 0);
}
// --------------------------------------------------------- Implementations
Methods
/**
* Implementation of regex matching algorithm.
* This calls itself recursively.
*/
private boolean match(String basePattern, String regexPattern, int baseAt, int
regexAt) {
if (log.isTraceEnabled()) {
log.trace("Base: " + basePattern);
log.trace("Regex: " + regexPattern);
log.trace("Base@" + baseAt);
log.trace("Regex@" + regexAt);
}
// check bounds
if (regexAt >= regexPattern.length()) {
// maybe we've got a match
if (baseAt >= basePattern.length()) {
// ok!
return true;
}
// run out early
return false;
} else {
if (baseAt >= basePattern.length()) {
// run out early
return false;
}
}
// ok both within bounds
char regexCurrent = regexPattern.charAt(regexAt);
switch (regexCurrent) {
case '*':
// this is the tricky case
// check for terminal
if (++regexAt >= regexPattern.length()) {
// this matches anything let - so return true
return true;
}
// go through every subsequent apperance of the next character
// and so if the rest of the regex matches
char nextRegex = regexPattern.charAt(regexAt);
if (log.isTraceEnabled()) {
log.trace("Searching for next '" + nextRegex + "' char");
}
int nextMatch = basePattern.indexOf(nextRegex, baseAt);
while (nextMatch != -1) {
if (log.isTraceEnabled()) {
log.trace("Trying '*' match@" + nextMatch);
}
if (match(basePattern, regexPattern, nextMatch, regexAt)) {
return true;
}
nextMatch = basePattern.indexOf(nextRegex, nextMatch + 1);
}
log.trace("No matches found.");
return false;
case '?':
// this matches anything
return match(basePattern, regexPattern, ++baseAt, ++regexAt);
default:
if (log.isTraceEnabled()) {
log.trace("Camparing " + regexCurrent + " to " +
basePattern.charAt(baseAt));
}
if (regexCurrent == basePattern.charAt(baseAt)) {
// still got more to go
return match(basePattern, regexPattern, ++baseAt, ++regexAt);
}
return false;
}
}
}
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