org.tuckey.web.filters.urlrewrite.substitution.BackReferenceReplacer Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of urlrewritefilter Show documentation
Show all versions of urlrewritefilter Show documentation
A Java Web Filter for any J2EE compliant web application server (such as Resin, Orion or Tomcat), which
allows you to rewrite URLs before they get to your code. It is a very powerful tool just like Apache's
mod_rewrite.
/**
* Copyright (c) 2005-2007, Paul Tuckey
* All rights reserved.
* ====================================================================
* Licensed under the BSD License. Text as follows.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - 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.
* - Neither the name tuckey.org nor the names of its contributors
* may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS 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
* COPYRIGHT OWNER OR 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.
* ====================================================================
*/
package org.tuckey.web.filters.urlrewrite.substitution;
import org.tuckey.web.filters.urlrewrite.ConditionMatch;
import org.tuckey.web.filters.urlrewrite.utils.Log;
import org.tuckey.web.filters.urlrewrite.utils.StringMatchingMatcher;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* Back references (eg, %1, %2 etc) replacer.
*
* @author Paul Tuckey
* @version $Revision: 1 $ $Date: 2006-08-01 21:40:28 +1200 (Tue, 01 Aug 2006) $
*/
public class BackReferenceReplacer implements SubstitutionFilter {
private static Log log = Log.getLog(BackReferenceReplacer.class);
private static Pattern backRefPattern = Pattern.compile("(? 0) {
Matcher backRefMatcher = backRefPattern.matcher(subjectOfReplacement);
StringBuffer sb = new StringBuffer();
boolean anyMatches = false;
int lastAppendPosition = 0;
while (backRefMatcher.find()) {
anyMatches = true;
int groupCount = backRefMatcher.groupCount();
if (groupCount < 1) {
log.error("group count on backref finder regex is not as expected");
if (log.isDebugEnabled()) {
log.error("backRefMatcher: " + backRefMatcher.toString());
}
continue;
}
String varStr = backRefMatcher.group(1);
boolean validBackref = false;
int varInt = 0;
log.debug("found " + varStr);
// now grab this match from lastConditionMatchMatcher
try {
varInt = Integer.parseInt(varStr);
if (varInt > lastCondMatcherGroupCount) {
log.error("backref %" + varInt + " not found in conditon ");
if (log.isDebugEnabled()) {
log.debug("condition matcher: " + lastConditionMatchMatcher.toString());
}
} else {
validBackref = true;
}
} catch (NumberFormatException nfe) {
log.error("could not parse backref " + varStr + " to number");
}
String conditionMatch = "";
if (validBackref) {
conditionMatch = lastConditionMatchMatcher.group(varInt);
}
String stringBeforeMatch = subjectOfReplacement.substring(lastAppendPosition, backRefMatcher.start());
sb.append(nextFilter.substitute(stringBeforeMatch, ctx));
sb.append(conditionMatch);
lastAppendPosition = backRefMatcher.end();
}
if (anyMatches) {
String stringAfterMatch = subjectOfReplacement.substring(lastAppendPosition);
sb.append(nextFilter.substitute(stringAfterMatch, ctx));
if (log.isDebugEnabled()) log.debug("replaced sb is " + sb);
return sb.toString();
}
}
}
return nextFilter.substitute(subjectOfReplacement, ctx);
}
}