propertyfileresolver.java

iiitAccessServer是一个用Java编写的基于规则的企业鉴别系统。它作为一个服务器工作

/*******************************************************************************
 * Copyright (C) 2002, 2003
 * ingenieurbuero fuer innovative informationstechnik (iiit)
 * Dipl.-Ing. Joerg Beckmann, Dortmund, Germany
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * This program 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 General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * version $Id: PropertyFileResolver.java,v 1.10 2003/04/13 21:09:56 joerg Exp $
 ******************************************************************************/

package de.iiit.access.server.plugins.parser;

import de.iiit.access.common.api.*;

import de.iiit.access.server.*;
import de.iiit.access.server.api.*;

import de.iiit.xmlconfig.*;

import java.util.*;
import java.util.regex.*;
import java.io.*;

import org.apache.log4j.Logger;

/** This is an example implementation of a resolver. This one reads its data from a
 * property file.
 * @version $Revision: 1.10 $ $Date: 2003/04/13 21:09:56 $
 */
public class PropertyFileResolver implements ResolverPluginIf
{
    /** CVS Version Tag */
    private static final String vcid = "$Id: PropertyFileResolver.java,v 1.10 2003/04/13 21:09:56 joerg Exp $";
    
    private static final String FILENAME = "FileName";

    private static Properties expressions = new Properties();

    private Logger logger = Logger.getLogger(this.getClass());

    private Pattern pOperator = Pattern.compile("[&+\\-]");         // + or - or &
    
    private boolean ignoreCase = false;
    
    /** Creates a new instance of PropertyFileResolver */
    public PropertyFileResolver()
    {
    }
    
    /** Creates a new instance of PropertyFileResolver
     * @param filename The name of the property file to read.
     * @throws FileNotFoundException if the file could not be found.
     * @throws IOException if an error occurred when reading from the input file.
     */    
    public PropertyFileResolver(String filename) throws FileNotFoundException, IOException
    {
        expressions.load(new FileInputStream(filename));
    }
    
    /** Initializes the server
     * @param config the configuration of the resolver. Currently the only parameter is
     * <CODE>FileName</CODE> which defines the name of the property file to read.
     */    
    public void initialize(Configuration config)
    {
        try
        {
            AccessServer.setVerifyUser(false);
            ignoreCase = AccessServer.getIgnoreCase();
            
            String filename = config.getAttribute(FILENAME);
            expressions.load(new FileInputStream(filename));
            
            if (ignoreCase)
            {
                Properties e = new Properties();
                
                Enumeration enum = expressions.keys();
                
                while (enum.hasMoreElements())
                {
                    String key = (String) enum.nextElement();
                    
                    e.put(key.toLowerCase(), ((String) expressions.get(key)).toLowerCase());
                }
                
                expressions = e;
            }
        }
        catch(Exception e)
        {
            logger.fatal("Fatal error", e);
            System.exit(1);
        }
    }
    
    /** This method is called by the AccessServer when the background threads should
     * stop because of a shutdown of the AccessServer itself.
     *
     */
    public void shutdown()
    {
        // Do nothing
    }
    
    /** This method is called by the AccessServer when the background thread should
     * start. It is called after the method initialize() is called for all plug-ins.
     *
     */
    public void start()
    {
        // Do nothing
    }
        
    /** Resolves the expression on top of the stack. If the result is also an expression
     * the parser is called to evaluate it.
     * @param argStack This stack includes all expressions and subexpressions of the current tree
     * inside the orginal expression.
     * @throws ParserException if there is something wrong with the expression. The most common cases are syntax
     * errors or circular references within the expression.
     * @return The set of users described by the expression.
     */    
    public Set resolve(ParserStackIf argStack) throws ParserException
    {
        String expression = (String) argStack.peek();
        Set result = null;

        String r = expressions.getProperty(expression);
        
        if (r != null) 
        {
            logger.info("Property = <" + r + ">");
            Matcher mOperator  = pOperator.matcher(r);
            
            if (mOperator.find())
            {
                argStack.pushArgument(r);
                Parser p = new Parser(this);
                result = p.evaluate(argStack);
                argStack.pop();
            }
            else
            {
                result = new HashSet();
                String parts[] = r.split("\\s*,\\s*");
                
                int iMax = parts.length;
                for (int i = 0; i < iMax; i++)
                    result.add(parts[i]);
            }
        }
        
        return result;
    }
    
    /** The evaluation is optimized in such way that
     * it only retrieves information regarding the given user name.
     * @param argStack This stack includes all expressions and subexpressions of the current tree
     * inside the orginal expression.
     * @param name The name of the user for whom the expression should be resolved.
     * @throws ParserException if there is something wrong with the expression. The most common cases are syntax
     * errors or circular references within the expression.
     * @return An optimized set of users. It is guaranteed that it is correct for the given user
     * but it is not guaranteed that it includes all users described by the expression.
     */    
    public Set resolve(ParserStackIf argStack, String name) throws ParserException
    {
        return resolve(argStack);
    }
    
    /** Verifies whether a user exists in the user database.
     * @param uid the user ID.
     * @return true if the user exists or if there is no user database, false if the user
     * doesn't exist.
     */    
    public boolean verifyUser(String uid)
    {
        return true;
    }
    
}

/**
 * $Log: PropertyFileResolver.java,v $
 * Revision 1.10  2003/04/13 21:09:56  joerg
 * Package structure modified
 *
 * Revision 1.9  2003/04/13 20:28:01  joerg
 * Package structure modified
 *
 * Revision 1.8  2003/04/13 20:16:42  joerg
 * Package structure modified
 *
 * Revision 1.7  2003/04/07 20:08:49  joerg
 * Improved JavaDoc.
 *
 * Revision 1.6  2003/01/17 19:56:27  joerg
 * Neue Methode verifyUser()
 *
 * Revision 1.5  2003/01/07 10:57:55  joerg
 * IgnoreCase eingebaut
 *
 * Revision 1.4  2003/01/01 21:04:18  joerg
 * Copyright-Statement aktualisiert
 *
 * Revision 1.3  2002/12/24 21:04:33  joerg
 * Umbau der Paketstruktur
 * iiitLdapPlugin integriert
 * JavaDoc-Kommentare weiter vervollstaendigt.
 *
 * Revision 1.2  2002/12/23 11:26:02  joerg
 * shutdown()-Methode hinzugefuegt.
 *
 * Revision 1.1  2002/12/19 15:24:23  joerg
 * Reparatur des CVS-Repositories
 *
 * Revision 1.4  2002/12/09 19:29:17  joerg
 * Versionsdaten in allen JavaDoc-Klassenbeschreibungen ergaenzt
 *
 * Revision 1.3  2002/12/09 16:32:26  joerg
 * JavaDoc Kommentare ergaenzt
 *
 * Revision 1.2  2002/11/27 16:39:40  joerg
 * Parameteruebergabe geaendert, um circulaere Recursion
 * zu erkennen
 *
 * Revision 1.1  2002/11/26 10:55:36  joerg
 * Package exprparser durch parser erstzt.
 *
 */