Tomcat example source code file (MemoryRealm.java)

This example Tomcat source code file (MemoryRealm.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Tomcat tags/keywords

arraylist, digester, digester, file, genericprincipal, genericprincipal, io, lifecycleexception, lifecycleexception, map, memoryrealm, memoryruleset, principal, security, string, string, util

The Tomcat MemoryRealm.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


package org.apache.catalina.realm;


import java.security.Principal;
import java.io.File;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import org.apache.catalina.LifecycleException;
import org.apache.catalina.util.StringManager;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import org.apache.tomcat.util.digester.Digester;


/**
 * Simple implementation of <b>Realm that reads an XML file to configure
 * the valid users, passwords, and roles.  The file format (and default file
 * location) are identical to those currently supported by Tomcat 3.X.
 * <p>
 * <strong>IMPLEMENTATION NOTE: It is assumed that the in-memory
 * collection representing our defined users (and their roles) is initialized
 * at application startup and never modified again.  Therefore, no thread
 * synchronization is performed around accesses to the principals collection.
 *
 * @author Craig R. McClanahan
 * @version $Revision: 543691 $ $Date: 2007-06-02 03:37:08 +0200 (sam., 02 juin 2007) $
 */

public class MemoryRealm  extends RealmBase {

    private static Log log = LogFactory.getLog(MemoryRealm.class);

    // ----------------------------------------------------- Instance Variables


    /**
     * The Digester we will use to process in-memory database files.
     */
    private static Digester digester = null;


    /**
     * Descriptive information about this Realm implementation.
     */
    protected final String info =
        "org.apache.catalina.realm.MemoryRealm/1.0";


    /**
     * Descriptive information about this Realm implementation.
     */

    protected static final String name = "MemoryRealm";


    /**
     * The pathname (absolute or relative to Catalina's current working
     * directory) of the XML file containing our database information.
     */
    private String pathname = "conf/tomcat-users.xml";


    /**
     * The set of valid Principals for this Realm, keyed by user name.
     */
    private Map<String,GenericPrincipal> principals =
        new HashMap<String,GenericPrincipal>();


    /**
     * The string manager for this package.
     */
    private static StringManager sm =
        StringManager.getManager(Constants.Package);


    // ------------------------------------------------------------- Properties


    /**
     * Return descriptive information about this Realm implementation and
     * the corresponding version number, in the format
     * <code><description>/<version>.
     */
    public String getInfo() {

        return info;

    }


    /**
     * Return the pathname of our XML file containing user definitions.
     */
    public String getPathname() {

        return pathname;

    }


    /**
     * Set the pathname of our XML file containing user definitions.  If a
     * relative pathname is specified, it is resolved against "catalina.base".
     *
     * @param pathname The new pathname
     */
    public void setPathname(String pathname) {

        this.pathname = pathname;

    }


    // --------------------------------------------------------- Public Methods


    /**
     * Return the Principal associated with the specified username and
     * credentials, if there is one; otherwise return <code>null.
     *
     * @param username Username of the Principal to look up
     * @param credentials Password or other credentials to use in
     *  authenticating this username
     */
    public Principal authenticate(String username, String credentials) {

        GenericPrincipal principal =
            (GenericPrincipal) principals.get(username);

        boolean validated = false;
        if (principal != null) {
            if (hasMessageDigest()) {
                // Hex hashes should be compared case-insensitive
                validated = (digest(credentials)
                             .equalsIgnoreCase(principal.getPassword()));
            } else {
                validated =
                    (digest(credentials).equals(principal.getPassword()));
            }
        }

        if (validated) {
            if (log.isDebugEnabled())
                log.debug(sm.getString("memoryRealm.authenticateSuccess", username));
            return (principal);
        } else {
            if (log.isDebugEnabled())
                log.debug(sm.getString("memoryRealm.authenticateFailure", username));
            return (null);
        }

    }


    // -------------------------------------------------------- Package Methods


    /**
     * Add a new user to the in-memory database.
     *
     * @param username User's username
     * @param password User's password (clear text)
     * @param roles Comma-delimited set of roles associated with this user
     */
    void addUser(String username, String password, String roles) {

        // Accumulate the list of roles for this user
        ArrayList<String> list = new ArrayList();
        roles += ",";
        while (true) {
            int comma = roles.indexOf(',');
            if (comma < 0)
                break;
            String role = roles.substring(0, comma).trim();
            list.add(role);
            roles = roles.substring(comma + 1);
        }

        // Construct and cache the Principal for this user
        GenericPrincipal principal =
            new GenericPrincipal(this, username, password, list);
        principals.put(username, principal);

    }


    // ------------------------------------------------------ Protected Methods


    /**
     * Return a configured <code>Digester to use for processing
     * the XML input file, creating a new one if necessary.
     */
    protected synchronized Digester getDigester() {

        if (digester == null) {
            digester = new Digester();
            digester.setValidating(false);
            digester.addRuleSet(new MemoryRuleSet());
        }
        return (digester);

    }


    /**
     * Return a short name for this Realm implementation.
     */
    protected String getName() {

        return (name);

    }


    /**
     * Return the password associated with the given principal's user name.
     */
    protected String getPassword(String username) {

        GenericPrincipal principal =
            (GenericPrincipal) principals.get(username);
        if (principal != null) {
            return (principal.getPassword());
        } else {
            return (null);
        }

    }


    /**
     * Return the Principal associated with the given user name.
     */
    protected Principal getPrincipal(String username) {

        return (Principal) principals.get(username);

    }

    /**
     * Returns the principals for this realm.
     *
     * @return The principals, keyed by user name (a String)
     */
    protected Map getPrincipals() {
        return principals;
    }


    // ------------------------------------------------------ Lifecycle Methods


    /**
     * Prepare for active use of the public methods of this Component.
     *
     * @exception LifecycleException if this component detects a fatal error
     *  that prevents it from being started
     */
    public synchronized void start() throws LifecycleException {

        // Perform normal superclass initialization
        super.start();

        // Validate the existence of our database file
        File file = new File(pathname);
        if (!file.isAbsolute())
            file = new File(System.getProperty("catalina.base"), pathname);
        if (!file.exists() || !file.canRead())
            throw new LifecycleException
                (sm.getString("memoryRealm.loadExist",
                              file.getAbsolutePath()));

        // Load the contents of the database file
        if (log.isDebugEnabled())
            log.debug(sm.getString("memoryRealm.loadPath",
                             file.getAbsolutePath()));
        Digester digester = getDigester();
        try {
            synchronized (digester) {
                digester.push(this);
                digester.parse(file);
            }
        } catch (Exception e) {
            throw new LifecycleException
                (sm.getString("memoryRealm.readXml"), e);
        } finally {
            digester.reset();
        }

    }


    /**
     * Gracefully shut down active use of the public methods of this Component.
     *
     * @exception LifecycleException if this component detects a fatal error
     *  that needs to be reported
     */
    public synchronized void stop() throws LifecycleException {

        // Perform normal superclass finalization
        super.stop();

        // No shutdown activities required

    }


}