001 /*-----------------------------------------------------------------------
002 * Copyright (C) 2006
003 * Associated Universities, Inc. Washington DC, USA.
004 * This program is free software; you can redistribute it and/or
005 * modify it under the terms of the GNU General Public License as
006 * published by the Free Software Foundation; either version 2 of
007 * the License, or (at your option) any later version.
008 *
009 * This program is distributed in the hope that it will be useful,
010 * but WITHOUT ANY WARRANTY; without even the implied warranty of
011 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
012 * GNU General Public License for more details.
013 *
014 * Correspondence concerning this software should be addressed as follows:
015 * Internet email: switz@nrao.edu
016 * Postal address: SSS Software
017 * National Radio Astronomy Observatory
018 * Post Office Box 0
019 * Socorro, NM 87801 USA
020 *-----------------------------------------------------------------------*/
021
022 package edu.nrao.sss.model.user;
023
024 import edu.nrao.sss.util.Filter;
025
026 /**
027 * A filter that operates on parameters.
028 * <p>
029 * <b>Revision Info:</b> <table style="margin-left:2em">
030 * <tr>
031 * <td>$Revision: 230 $</td>
032 * </tr>
033 * <tr>
034 * <td>$Date: 2007-01-02 14:37:07 -0700 (Tue, 02 Jan 2007) $</td>
035 * </tr>
036 * <tr>
037 * <td>$Author: dharland $</td>
038 * </tr>
039 * </table>
040 * </p>
041 *
042 * @author David M. Harland
043 * @since 2006-06-27
044 */
045 public class UserFilter implements Filter<User> {
046 private static final String ANY_PATTERN = null;
047
048 private String lastNamePattern;
049
050
051 /**
052 * Creates a new wide-open filter that allows all parameters to pass.
053 */
054 public UserFilter() {
055 clearAll();
056 }
057
058 // ============================================================================
059 // CLEARING THE FILTERING CRITERIA
060 // ============================================================================
061
062 /**
063 * Returns <i>true</i> if this filter allows the given parameter to pass
064 * through it. <i>Null</i> parameters are always blocked.
065 * <p>
066 * The logic for allowing or blocking a parameter is somewhat complex. See
067 * {@link #blocks(User)} for details.
068 * </p>
069 *
070 * @param param
071 * the parameter to be filtered.
072 *
073 * @return <i>true</i> if this filter allows {@code param} to pass through
074 * it.
075 */
076 public boolean allows(User param) {
077 return !blocks(param);
078 }
079
080 /**
081 * Returns <i>true</i> if this filter blocks the given parameter. <i>Null</i>
082 * parameters are always blocked.
083 *
084 * @param user
085 * the parameter to be filtered.
086 *
087 * @return <i>true</i> if this filter blocks {@code user}.
088 */
089 public boolean blocks(User user) {
090 // Filter blocks all null users
091 if (user == null)
092 return true;
093
094 if ((lastNamePattern != ANY_PATTERN) &&
095 (user.getLastName() == null ||
096 !user.getLastName().matches(lastNamePattern)))
097 return true;
098
099 return false;
100 }
101
102 /**
103 * Sets this filter to a wide-open state. After this call all filtering
104 * criteria will be in their wide-open states and this filter will allow all
105 * parameters to pass.
106 */
107 public void clearAll() {
108 clearLastNamePattern();
109 }
110
111 /**
112 * Sets the band criterion to its wide-open state.
113 *
114 * @see #setLastNamePattern(String)
115 */
116 public void clearLastNamePattern() {
117 lastNamePattern = ANY_PATTERN;
118 }
119
120
121 /**
122 * Sets a regular expression for matching the bandss of parameters. Only
123 * parameters whose bands are matched by {@code regex} are allowed to pass
124 * through this filter. If parameters should not be filtered based on their
125 * bands, call {@link #clearLastNamePattern()}.
126 *
127 * @param regex
128 * a regular expression for matching the bandss of parameters.
129 */
130 public void setLastNamePattern(String regex) {
131 lastNamePattern = (regex == null) ? ANY_PATTERN : regex;
132 }
133
134 }