/*------------------------------------------------------------------------------
Name: GnuRegexFilter.java
Project: xmlBlaster.org
Copyright: xmlBlaster.org, see xmlBlaster-LICENSE file
Comment: Support check of message content with regular expressions.
------------------------------------------------------------------------------*/
package org.xmlBlaster.engine.mime.regex;
import java.util.logging.Logger;
import java.util.logging.Level;
import org.xmlBlaster.util.plugin.I_Plugin;
import org.xmlBlaster.util.XmlBlasterException;
import org.xmlBlaster.util.def.ErrorCode;
import org.xmlBlaster.authentication.SessionInfo;
import org.xmlBlaster.util.def.Constants;
import org.xmlBlaster.util.MsgUnit;
import org.xmlBlaster.engine.mime.I_AccessFilter;
import org.xmlBlaster.engine.mime.Query;
import org.xmlBlaster.engine.ServerScope;
import gnu.regexp.RE;
/**
* This regex plugin allows to filter message contents with regular expressions.
* <p />
* Message contents which don't match the regular expression are not send via update()
* or updateOneway() to the subscriber. The same filter may be used
* for the synchronous get() access and for clusters to map messages to master nodes.
* <p />
* Please register this plugin in xmlBlaster.properties:
* <pre>
* MimeAccessPlugin[GnuRegexFilter][1.0]=org.xmlBlaster.engine.mime.regex.GnuRegexFilter
* </pre>
* Plugins must implement the I_Plugin interface to be loadable by the PluginManager
* and must implement the I_AccessFilter interface to be usable as a filter.
* <p />
* <p />
* NOTE: Since JDK 1.4 we have a java.util.regex package, but regrettably this can't be
* used with JDK 1.2 or JDK 1.3. If you want to use Suns package just copy this class
* and code it with suns implementation in our match() method:
* <pre>
* import java.util.regex.Pattern;
* import java.util.regex.Matcher;
* ...
*
* query.setPreparedQuery(Pattern.compile(query.getQuery()));
* ...
* Matcher m = preparedQuery.matcher(msgUnit.getContentStr());
* return m.matches();
* </pre>
* @author xmlBlaster@marcelruff.info
* @see <a href="http://www.cacas.org/java/gnu/regexp/" target="others">The GNU regex package</a>
*/
public class GnuRegexFilter implements I_Plugin, I_AccessFilter
{
private final String ME = "GnuRegexFilter";
private ServerScope glob;
private static Logger log = Logger.getLogger(GnuRegexFilter.class.getName());
/**
* This is called after instantiation of the plugin
* @param glob The Global handle of this xmlBlaster server instance.
*/
public void initialize(ServerScope glob) {
this.glob = glob;
log.info("Filter is initialized, regular expression checks for all mime types");
}
/**
* This method is called by the PluginManager (enforced by I_Plugin).
* @see org.xmlBlaster.util.plugin.I_Plugin#init(org.xmlBlaster.util.Global,org.xmlBlaster.util.plugin.PluginInfo)
*/
public void init(org.xmlBlaster.util.Global glob, org.xmlBlaster.util.plugin.PluginInfo pluginInfo) {
}
/**
* Return plugin type for Plugin loader
* @return "GnuRegexFilter"
*/
public String getType() {
return "GnuRegexFilter";
}
/**
* Return plugin version for Plugin loader
* @return "1.0"
*/
public String getVersion() {
return "1.0";
}
/**
* Get a human readable name of this filter implementation
* @return "GnuRegexFilter"
*/
public String getName() {
return "GnuRegexFilter";
}
/**
* Get the content MIME type for which this plugin applies
* @return "*" This plugin handles all mime types
*/
public String[] getMimeTypes() {
String[] mimeTypes = { "*" };
return mimeTypes;
}
/**
* Get the content MIME version number for which this plugin applies
* @return "1.0" (this is the default version number)
*/
public String[] getMimeExtended() {
String[] mimeExtended = { Constants.DEFAULT_CONTENT_MIME_EXTENDED }; // "1.0"
return mimeExtended;
}
/**
* Check if the filter rule matches for this message.
* @param publisher The subject object describing the publisher
* @param receiver The subject object describing the receiver
* @param msgUnit The message to check
* @param query The Query instance holding the regular expression from your filter.<br />
* @return true The filter regex expression matches the message content.
* @exception see I_AccessFilter#match()
*/
public boolean match(SessionInfo receiver, MsgUnit msgUnit, Query query) throws XmlBlasterException {
if (msgUnit == null) {
Thread.dumpStack();
throw new XmlBlasterException(glob, ErrorCode.INTERNAL_ILLEGALARGUMENT, ME, "Illegal argument in regex match() call");
}
RE expression;
if (query.getPreparedQuery() == null) {
try {
expression = new RE(query.getQuery());
query.setPreparedQuery(expression); // for better performance we remember the regex expression
} catch (gnu.regexp.REException e) {
log.severe("Can't compile regular filter expression '" + query + "':" + e.toString());
throw new XmlBlasterException(glob, ErrorCode.USER_CONFIGURATION, ME, "Can't compile regular filter expression '" + query + "':" + e.toString());
}
}
else
expression = (RE)query.getPreparedQuery();
return expression.isMatch(msgUnit.getContentStr());
}
public void shutdown() {
}
}