Merge pull request #248 from glyptodon/concurrent-policy

GUAC-830: Implement concurrency policy attributes

extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-base/src/main/java/org/glyptodon/guacamole/auth/jdbc/connection/ConnectionModel.java

@@ -42,6 +42,20 @@ public class ConnectionModel extends GroupedObjectModel {
      */
     private String protocol;
 
+    /**
+     * The maximum number of connections that can be established to this
+     * connection concurrently, zero if no restriction applies, or null if the
+     * default restrictions should be applied.
+     */
+    private Integer maxConnections;
+
+    /**
+     * The maximum number of connections that can be established to this
+     * connection concurrently by any one user, zero if no restriction applies,
+     * or null if the default restrictions should be applied.
+     */
+    private Integer maxConnectionsPerUser;
+
     /**
      * Creates a new, empty connection.
      */
@@ -89,6 +103,58 @@ public class ConnectionModel extends GroupedObjectModel {
         this.protocol = protocol;
     }
 
+    /**
+     * Returns the maximum number of connections that can be established to
+     * this connection concurrently.
+     *
+     * @return
+     *     The maximum number of connections that can be established to this
+     *     connection concurrently, zero if no restriction applies, or null if
+     *     the default restrictions should be applied.
+     */
+    public Integer getMaxConnections() {
+        return maxConnections;
+    }
+
+    /**
+     * Sets the maximum number of connections that can be established to this
+     * connection concurrently.
+     *
+     * @param maxConnections
+     *     The maximum number of connections that can be established to this
+     *     connection concurrently, zero if no restriction applies, or null if
+     *     the default restrictions should be applied.
+     */
+    public void setMaxConnections(Integer maxConnections) {
+        this.maxConnections = maxConnections;
+    }
+
+    /**
+     * Returns the maximum number of connections that can be established to
+     * this connection concurrently by any one user.
+     *
+     * @return
+     *     The maximum number of connections that can be established to this
+     *     connection concurrently by any one user, zero if no restriction
+     *     applies, or null if the default restrictions should be applied.
+     */
+    public Integer getMaxConnectionsPerUser() {
+        return maxConnectionsPerUser;
+    }
+
+    /**
+     * Sets the maximum number of connections that can be established to this
+     * connection concurrently by any one user.
+     *
+     * @param maxConnectionsPerUser
+     *     The maximum number of connections that can be established to this
+     *     connection concurrently by any one user, zero if no restriction
+     *     applies, or null if the default restrictions should be applied.
+     */
+    public void setMaxConnectionsPerUser(Integer maxConnectionsPerUser) {
+        this.maxConnectionsPerUser = maxConnectionsPerUser;
+    }
+
     @Override
     public String getIdentifier() {
 

extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-base/src/main/java/org/glyptodon/guacamole/auth/jdbc/connection/ModeledConnection.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2013 Glyptodon LLC
+ * Copyright (C) 2015 Glyptodon LLC
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -24,17 +24,25 @@ package org.glyptodon.guacamole.auth.jdbc.connection;
 
 import com.google.inject.Inject;
 import com.google.inject.Provider;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import org.glyptodon.guacamole.auth.jdbc.tunnel.GuacamoleTunnelService;
 import org.glyptodon.guacamole.GuacamoleException;
 import org.glyptodon.guacamole.auth.jdbc.base.ModeledGroupedDirectoryObject;
+import org.glyptodon.guacamole.form.Field;
+import org.glyptodon.guacamole.form.Form;
+import org.glyptodon.guacamole.form.NumericField;
 import org.glyptodon.guacamole.net.GuacamoleTunnel;
 import org.glyptodon.guacamole.net.auth.Connection;
 import org.glyptodon.guacamole.net.auth.ConnectionRecord;
 import org.glyptodon.guacamole.protocol.GuacamoleClientInformation;
 import org.glyptodon.guacamole.protocol.GuacamoleConfiguration;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * An implementation of the Connection object which is backed by a database
@@ -46,6 +54,40 @@ import org.glyptodon.guacamole.protocol.GuacamoleConfiguration;
 public class ModeledConnection extends ModeledGroupedDirectoryObject<ConnectionModel>
     implements Connection {
 
+    /**
+     * Logger for this class.
+     */
+    private static final Logger logger = LoggerFactory.getLogger(ModeledConnection.class);
+
+    /**
+     * The name of the attribute which controls the maximum number of
+     * concurrent connections.
+     */
+    public static final String MAX_CONNECTIONS_NAME = "max-connections";
+
+    /**
+     * The name of the attribute which controls the maximum number of
+     * concurrent connections per user.
+     */
+    public static final String MAX_CONNECTIONS_PER_USER_NAME = "max-connections-per-user";
+
+    /**
+     * All attributes related to restricting user accounts, within a logical
+     * form.
+     */
+    public static final Form CONCURRENCY_LIMITS = new Form("concurrency", Arrays.<Field>asList(
+        new NumericField(MAX_CONNECTIONS_NAME),
+        new NumericField(MAX_CONNECTIONS_PER_USER_NAME)
+    ));
+
+    /**
+     * All possible attributes of connection objects organized as individual,
+     * logical forms.
+     */
+    public static final Collection<Form> ATTRIBUTES = Collections.unmodifiableCollection(Arrays.asList(
+        CONCURRENCY_LIMITS
+    ));
+
     /**
      * Service for managing connections.
      */
@@ -127,12 +169,35 @@ public class ModeledConnection extends ModeledGroupedDirectoryObject<ConnectionM
 
     @Override
     public Map<String, String> getAttributes() {
-        return Collections.<String, String>emptyMap();
+
+        Map<String, String> attributes = new HashMap<String, String>();
+
+        // Set connection limit attribute
+        attributes.put(MAX_CONNECTIONS_NAME, NumericField.format(getModel().getMaxConnections()));
+
+        // Set per-user connection limit attribute
+        attributes.put(MAX_CONNECTIONS_PER_USER_NAME, NumericField.format(getModel().getMaxConnectionsPerUser()));
+
+        return attributes;
     }
 
     @Override
     public void setAttributes(Map<String, String> attributes) {
-        // Drop all attributes - none currently supported
+
+        // Translate connection limit attribute
+        try { getModel().setMaxConnections(NumericField.parse(attributes.get(MAX_CONNECTIONS_NAME))); }
+        catch (NumberFormatException e) {
+            logger.warn("Not setting maximum connections: {}", e.getMessage());
+            logger.debug("Unable to parse numeric attribute.", e);
+        }
+
+        // Translate per-user connection limit attribute
+        try { getModel().setMaxConnectionsPerUser(NumericField.parse(attributes.get(MAX_CONNECTIONS_PER_USER_NAME))); }
+        catch (NumberFormatException e) {
+            logger.warn("Not setting maximum connections per user: {}", e.getMessage());
+            logger.debug("Unable to parse numeric attribute.", e);
+        }
+
     }
 
 }

extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-base/src/main/java/org/glyptodon/guacamole/auth/jdbc/connectiongroup/ConnectionGroupModel.java

@@ -43,6 +43,20 @@ public class ConnectionGroupModel extends GroupedObjectModel {
      */
     private ConnectionGroup.Type type;
 
+    /**
+     * The maximum number of connections that can be established to this
+     * connection group concurrently, zero if no restriction applies, or
+     * null if the default restrictions should be applied.
+     */
+    private Integer maxConnections;
+
+    /**
+     * The maximum number of connections that can be established to this
+     * connection group concurrently by any one user, zero if no restriction
+     * applies, or null if the default restrictions should be applied.
+     */
+    private Integer maxConnectionsPerUser;
+
     /**
      * Creates a new, empty connection group.
      */
@@ -91,6 +105,60 @@ public class ConnectionGroupModel extends GroupedObjectModel {
         this.type = type;
     }
 
+    /**
+     * Returns the maximum number of connections that can be established to
+     * this connection group concurrently.
+     *
+     * @return
+     *     The maximum number of connections that can be established to this
+     *     connection group concurrently, zero if no restriction applies, or
+     *     null if the default restrictions should be applied.
+     */
+    public Integer getMaxConnections() {
+        return maxConnections;
+    }
+
+    /**
+     * Sets the maximum number of connections that can be established to this
+     * connection group concurrently.
+     *
+     * @param maxConnections
+     *     The maximum number of connections that can be established to this
+     *     connection group concurrently, zero if no restriction applies, or
+     *     null if the default restrictions should be applied.
+     */
+    public void setMaxConnections(Integer maxConnections) {
+        this.maxConnections = maxConnections;
+    }
+
+    /**
+     * Returns the maximum number of connections that can be established to
+     * this connection group concurrently by any one user.
+     *
+     * @return
+     *     The maximum number of connections that can be established to this
+     *     connection group concurrently by any one user, zero if no
+     *     restriction applies, or null if the default restrictions should be
+     *     applied.
+     */
+    public Integer getMaxConnectionsPerUser() {
+        return maxConnectionsPerUser;
+    }
+
+    /**
+     * Sets the maximum number of connections that can be established to this
+     * connection group concurrently by any one user.
+     *
+     * @param maxConnectionsPerUser
+     *     The maximum number of connections that can be established to this
+     *     connection group concurrently by any one user, zero if no
+     *     restriction applies, or null if the default restrictions should be
+     *     applied.
+     */
+    public void setMaxConnectionsPerUser(Integer maxConnectionsPerUser) {
+        this.maxConnectionsPerUser = maxConnectionsPerUser;
+    }
+
     @Override
     public String getIdentifier() {
 

extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-base/src/main/java/org/glyptodon/guacamole/auth/jdbc/connectiongroup/ModeledConnectionGroup.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2013 Glyptodon LLC
+ * Copyright (C) 2015 Glyptodon LLC
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -23,26 +23,69 @@
 package org.glyptodon.guacamole.auth.jdbc.connectiongroup;
 
 import com.google.inject.Inject;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.Map;
 import java.util.Set;
 import org.glyptodon.guacamole.auth.jdbc.connection.ConnectionService;
 import org.glyptodon.guacamole.auth.jdbc.tunnel.GuacamoleTunnelService;
 import org.glyptodon.guacamole.GuacamoleException;
 import org.glyptodon.guacamole.auth.jdbc.base.ModeledGroupedDirectoryObject;
+import org.glyptodon.guacamole.form.Field;
+import org.glyptodon.guacamole.form.Form;
+import org.glyptodon.guacamole.form.NumericField;
 import org.glyptodon.guacamole.net.GuacamoleTunnel;
 import org.glyptodon.guacamole.net.auth.ConnectionGroup;
 import org.glyptodon.guacamole.protocol.GuacamoleClientInformation;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * An implementation of the ConnectionGroup object which is backed by a
  * database model.
  *
  * @author James Muehlner
+ * @author Michael Jumper
  */
 public class ModeledConnectionGroup extends ModeledGroupedDirectoryObject<ConnectionGroupModel>
     implements ConnectionGroup {
 
+    /**
+     * Logger for this class.
+     */
+    private static final Logger logger = LoggerFactory.getLogger(ModeledConnectionGroup.class);
+
+    /**
+     * The name of the attribute which controls the maximum number of
+     * concurrent connections.
+     */
+    public static final String MAX_CONNECTIONS_NAME = "max-connections";
+
+    /**
+     * The name of the attribute which controls the maximum number of
+     * concurrent connections per user.
+     */
+    public static final String MAX_CONNECTIONS_PER_USER_NAME = "max-connections-per-user";
+
+    /**
+     * All attributes related to restricting user accounts, within a logical
+     * form.
+     */
+    public static final Form CONCURRENCY_LIMITS = new Form("concurrency", Arrays.<Field>asList(
+        new NumericField(MAX_CONNECTIONS_NAME),
+        new NumericField(MAX_CONNECTIONS_PER_USER_NAME)
+    ));
+
+    /**
+     * All possible attributes of connection group objects organized as
+     * individual, logical forms.
+     */
+    public static final Collection<Form> ATTRIBUTES = Collections.unmodifiableCollection(Arrays.asList(
+        CONCURRENCY_LIMITS
+    ));
+
     /**
      * Service for managing connections.
      */
@@ -112,12 +155,35 @@ public class ModeledConnectionGroup extends ModeledGroupedDirectoryObject<Connec
 
     @Override
     public Map<String, String> getAttributes() {
-        return Collections.<String, String>emptyMap();
+
+        Map<String, String> attributes = new HashMap<String, String>();
+
+        // Set connection limit attribute
+        attributes.put(MAX_CONNECTIONS_NAME, NumericField.format(getModel().getMaxConnections()));
+
+        // Set per-user connection limit attribute
+        attributes.put(MAX_CONNECTIONS_PER_USER_NAME, NumericField.format(getModel().getMaxConnectionsPerUser()));
+
+        return attributes;
     }
 
     @Override
     public void setAttributes(Map<String, String> attributes) {
-        // Drop all attributes - none currently supported
+
+        // Translate connection limit attribute
+        try { getModel().setMaxConnections(NumericField.parse(attributes.get(MAX_CONNECTIONS_NAME))); }
+        catch (NumberFormatException e) {
+            logger.warn("Not setting maximum connections: {}", e.getMessage());
+            logger.debug("Unable to parse numeric attribute.", e);
+        }
+
+        // Translate per-user connection limit attribute
+        try { getModel().setMaxConnectionsPerUser(NumericField.parse(attributes.get(MAX_CONNECTIONS_PER_USER_NAME))); }
+        catch (NumberFormatException e) {
+            logger.warn("Not setting maximum connections per user: {}", e.getMessage());
+            logger.debug("Unable to parse numeric attribute.", e);
+        }
+
     }
 
 }

extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-base/src/main/java/org/glyptodon/guacamole/auth/jdbc/tunnel/ConfigurableGuacamoleTunnelService.java

@@ -160,7 +160,7 @@ public class ConfigurableGuacamoleTunnelService
             int count = multiset.count(value);
 
             // Bail out if the maximum has already been reached
-            if (count >= max || max == 0)
+            if (count >= max && max != 0)
                 return false;
 
             // Attempt to add one more value
@@ -200,14 +200,23 @@ public class ConfigurableGuacamoleTunnelService
         // Return the first unreserved connection
         for (ModeledConnection connection : sortedConnections) {
 
+            // Determine per-user limits on this connection
+            Integer connectionMaxConnectionsPerUser = connection.getModel().getMaxConnectionsPerUser();
+            if (connectionMaxConnectionsPerUser == null)
+                connectionMaxConnectionsPerUser = connectionDefaultMaxConnectionsPerUser;
+
+            // Determine overall limits on this connection
+            Integer connectionMaxConnections = connection.getModel().getMaxConnections();
+            if (connectionMaxConnections == null)
+                connectionMaxConnections = connectionDefaultMaxConnections;
+
             // Attempt to aquire connection according to per-user limits
             Seat seat = new Seat(username, connection.getIdentifier());
-            if (tryAdd(activeSeats, seat,
+            if (tryAdd(activeSeats, seat, connectionMaxConnectionsPerUser)) {
-                    connectionDefaultMaxConnectionsPerUser)) {
 
                 // Attempt to aquire connection according to overall limits
                 if (tryAdd(activeConnections, connection.getIdentifier(),
-                        connectionDefaultMaxConnections))
+                        connectionMaxConnections))
                     return connection;
 
                 // Acquire failed - retry with next connection
@@ -222,7 +231,7 @@ public class ConfigurableGuacamoleTunnelService
 
         // Too many connections by this user
         if (userSpecificFailure)
-            throw new GuacamoleClientTooManyException("Cannot connect. Connection group already in use by this user.");
+            throw new GuacamoleClientTooManyException("Cannot connect. Connection already in use by this user.");
 
         // Too many connections, but not necessarily due purely to this user
         else
@@ -243,14 +252,24 @@ public class ConfigurableGuacamoleTunnelService
         // Get username
         String username = user.getUser().getIdentifier();
 
+        // Determine per-user limits on this connection group
+        Integer connectionGroupMaxConnectionsPerUser = connectionGroup.getModel().getMaxConnectionsPerUser();
+        if (connectionGroupMaxConnectionsPerUser == null)
+            connectionGroupMaxConnectionsPerUser = connectionGroupDefaultMaxConnectionsPerUser;
+
+        // Determine overall limits on this connection group
+        Integer connectionGroupMaxConnections = connectionGroup.getModel().getMaxConnections();
+        if (connectionGroupMaxConnections == null)
+            connectionGroupMaxConnections = connectionGroupDefaultMaxConnections;
+
         // Attempt to aquire connection group according to per-user limits
         Seat seat = new Seat(username, connectionGroup.getIdentifier());
         if (tryAdd(activeGroupSeats, seat,
-                connectionGroupDefaultMaxConnectionsPerUser)) {
+                connectionGroupMaxConnectionsPerUser)) {
 
             // Attempt to aquire connection group according to overall limits
             if (tryAdd(activeGroups, connectionGroup.getIdentifier(),
-                    connectionGroupDefaultMaxConnections))
+                    connectionGroupMaxConnections))
                 return;
 
             // Acquire failed

extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-base/src/main/java/org/glyptodon/guacamole/auth/jdbc/user/ModeledUser.java

@@ -25,9 +25,7 @@ package org.glyptodon.guacamole.auth.jdbc.user;
 import com.google.inject.Inject;
 import java.sql.Date;
 import java.sql.Time;
-import java.text.DateFormat;
 import java.text.ParseException;
-import java.text.SimpleDateFormat;
 import java.util.Arrays;
 import java.util.Calendar;
 import java.util.Collection;
@@ -268,40 +266,39 @@ public class ModeledUser extends ModeledDirectoryObject<UserModel> implements Us
         return userPermissionService.getPermissionSet(getCurrentUser(), this);
     }
 
-    /**
+    @Override
-     * Converts the given date into a string which follows the format used by
+    public Map<String, String> getAttributes() {
-     * date attributes.
-     *
-     * @param date
-     *     The date value to format, which may be null.
-     *
-     * @return
-     *     The formatted date, or null if the provided time was null.
-     */
-    private String formatDate(Date date) {
-        DateFormat dateFormat = new SimpleDateFormat(DateField.FORMAT);
-        return date == null ? null : dateFormat.format(date);
-    }
 
-    /**
+        Map<String, String> attributes = new HashMap<String, String>();
-     * Converts the given time into a string which follows the format used by
+
-     * time attributes.
+        // Set disabled attribute
-     *
+        attributes.put(DISABLED_ATTRIBUTE_NAME, getModel().isDisabled() ? "true" : null);
-     * @param time
+
-     *     The time value to format, which may be null.
+        // Set password expired attribute
-     *
+        attributes.put(EXPIRED_ATTRIBUTE_NAME, getModel().isExpired() ? "true" : null);
-     * @return
+
-     *     The formatted time, or null if the provided time was null.
+        // Set access window start time
-     */
+        attributes.put(ACCESS_WINDOW_START_ATTRIBUTE_NAME, TimeField.format(getModel().getAccessWindowStart()));
-    private String formatTime(Time time) {
+
-        DateFormat timeFormat = new SimpleDateFormat(TimeField.FORMAT);
+        // Set access window end time
-        return time == null ? null : timeFormat.format(time);
+        attributes.put(ACCESS_WINDOW_END_ATTRIBUTE_NAME, TimeField.format(getModel().getAccessWindowEnd()));
+
+        // Set account validity start date
+        attributes.put(VALID_FROM_ATTRIBUTE_NAME, DateField.format(getModel().getValidFrom()));
+
+        // Set account validity end date
+        attributes.put(VALID_UNTIL_ATTRIBUTE_NAME, DateField.format(getModel().getValidUntil()));
+
+        // Set timezone attribute
+        attributes.put(TIMEZONE_ATTRIBUTE_NAME, getModel().getTimeZone());
+
+        return attributes;
     }
 
     /**
      * Parses the given string into a corresponding date. The string must
      * follow the standard format used by date attributes, as defined by
-     * DATE_FORMAT and as would be produced by formatDate().
+     * DateField.FORMAT and as would be produced by DateField.format().
      *
      * @param dateString
      *     The date string to parse, which may be null.
@@ -318,19 +315,19 @@ public class ModeledUser extends ModeledDirectoryObject<UserModel> implements Us
     throws ParseException {
 
         // Return null if no date provided
-        if (dateString == null || dateString.isEmpty())
+        java.util.Date parsedDate = DateField.parse(dateString);
+        if (parsedDate == null)
             return null;
 
-        // Parse date according to format
+        // Convert to SQL Date
-        DateFormat dateFormat = new SimpleDateFormat(DateField.FORMAT);
+        return new Date(parsedDate.getTime());
-        return new Date(dateFormat.parse(dateString).getTime());
 
     }
 
     /**
      * Parses the given string into a corresponding time. The string must
      * follow the standard format used by time attributes, as defined by
-     * TIME_FORMAT and as would be produced by formatTime().
+     * TimeField.FORMAT and as would be produced by TimeField.format().
      *
      * @param timeString
      *     The time string to parse, which may be null.
@@ -347,67 +344,15 @@ public class ModeledUser extends ModeledDirectoryObject<UserModel> implements Us
     throws ParseException {
 
         // Return null if no time provided
-        if (timeString == null || timeString.isEmpty())
+        java.util.Date parsedDate = TimeField.parse(timeString);
+        if (parsedDate == null)
             return null;
 
-        // Parse time according to format
+        // Convert to SQL Time 
-        DateFormat timeFormat = new SimpleDateFormat(TimeField.FORMAT);
+        return new Time(parsedDate.getTime());
-        return new Time(timeFormat.parse(timeString).getTime());
 
     }
 
-    /**
-     * Parses the given string into a time zone ID string. As these strings are
-     * equivalent, the only transformation currently performed by this function
-     * is to ensure that a blank time zone string is parsed into null.
-     *
-     * @param timeZone
-     *     The time zone string to parse, which may be null.
-     *
-     * @return
-     *     The ID of the time zone corresponding to the given string, or null
-     *     if the given time zone string was null or blank.
-     */
-    private String parseTimeZone(String timeZone) {
-
-        // Return null if no time zone provided
-        if (timeZone == null || timeZone.isEmpty())
-            return null;
-
-        // Otherwise, assume time zone is valid
-        return timeZone;
-
-    }
-
-    @Override
-    public Map<String, String> getAttributes() {
-
-        Map<String, String> attributes = new HashMap<String, String>();
-
-        // Set disabled attribute
-        attributes.put(DISABLED_ATTRIBUTE_NAME, getModel().isDisabled() ? "true" : null);
-
-        // Set password expired attribute
-        attributes.put(EXPIRED_ATTRIBUTE_NAME, getModel().isExpired() ? "true" : null);
-
-        // Set access window start time
-        attributes.put(ACCESS_WINDOW_START_ATTRIBUTE_NAME, formatTime(getModel().getAccessWindowStart()));
-
-        // Set access window end time
-        attributes.put(ACCESS_WINDOW_END_ATTRIBUTE_NAME, formatTime(getModel().getAccessWindowEnd()));
-
-        // Set account validity start date
-        attributes.put(VALID_FROM_ATTRIBUTE_NAME, formatDate(getModel().getValidFrom()));
-
-        // Set account validity end date
-        attributes.put(VALID_UNTIL_ATTRIBUTE_NAME, formatDate(getModel().getValidUntil()));
-
-        // Set timezone attribute
-        attributes.put(TIMEZONE_ATTRIBUTE_NAME, getModel().getTimeZone());
-
-        return attributes;
-    }
-
     @Override
     public void setAttributes(Map<String, String> attributes) {
 
@@ -446,7 +391,7 @@ public class ModeledUser extends ModeledDirectoryObject<UserModel> implements Us
         }
 
         // Translate timezone attribute
-        getModel().setTimeZone(parseTimeZone(attributes.get(TIMEZONE_ATTRIBUTE_NAME)));
+        getModel().setTimeZone(TimeZoneField.parse(attributes.get(TIMEZONE_ATTRIBUTE_NAME)));
 
     }
 

extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-base/src/main/java/org/glyptodon/guacamole/auth/jdbc/user/UserContext.java

@@ -29,10 +29,11 @@ import org.glyptodon.guacamole.auth.jdbc.connection.ConnectionDirectory;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
 import java.util.Collection;
-import java.util.Collections;
 import org.glyptodon.guacamole.GuacamoleException;
 import org.glyptodon.guacamole.auth.jdbc.base.RestrictedObject;
 import org.glyptodon.guacamole.auth.jdbc.activeconnection.ActiveConnectionDirectory;
+import org.glyptodon.guacamole.auth.jdbc.connection.ModeledConnection;
+import org.glyptodon.guacamole.auth.jdbc.connectiongroup.ModeledConnectionGroup;
 import org.glyptodon.guacamole.form.Form;
 import org.glyptodon.guacamole.net.auth.ActiveConnection;
 import org.glyptodon.guacamole.net.auth.Connection;
@@ -140,12 +141,12 @@ public class UserContext extends RestrictedObject
 
     @Override
     public Collection<Form> getConnectionAttributes() {
-        return Collections.<Form>emptyList();
+        return ModeledConnection.ATTRIBUTES;
     }
 
     @Override
     public Collection<Form> getConnectionGroupAttributes() {
-        return Collections.<Form>emptyList();
+        return ModeledConnectionGroup.ATTRIBUTES;
     }
 
 }

extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-base/src/main/resources/translations/en.json

@@ -15,6 +15,24 @@
 
     },
 
+    "CONNECTION_ATTRIBUTES" : {
+
+        "FIELD_HEADER_MAX_CONNECTIONS"          : "Maximum number of connections:",
+        "FIELD_HEADER_MAX_CONNECTIONS_PER_USER" : "Maximum number of connections per user:",
+
+        "SECTION_HEADER_CONCURRENCY" : "Concurrency Limits"
+
+    },
+
+    "CONNECTION_GROUP_ATTRIBUTES" : {
+
+        "FIELD_HEADER_MAX_CONNECTIONS"          : "Maximum number of connections:",
+        "FIELD_HEADER_MAX_CONNECTIONS_PER_USER" : "Maximum number of connections per user:",
+
+        "SECTION_HEADER_CONCURRENCY" : "Concurrency Limits (Balancing Groups)"
+
+    },
+
     "USER_ATTRIBUTES" : {
 
         "FIELD_HEADER_DISABLED"            : "Login disabled:",

extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-mysql/schema/001-create-schema.sql

@@ -32,6 +32,10 @@ CREATE TABLE `guacamole_connection_group` (
   `type`                  enum('ORGANIZATIONAL',
                                'BALANCING') NOT NULL DEFAULT 'ORGANIZATIONAL',
 
+  -- Concurrency limits
+  `max_connections`          int(11),
+  `max_connections_per_user` int(11),
+
   PRIMARY KEY (`connection_group_id`),
   UNIQUE KEY `connection_group_name_parent` (`connection_group_name`, `parent_id`),
 
@@ -54,6 +58,10 @@ CREATE TABLE `guacamole_connection` (
   `parent_id`           int(11),
   `protocol`            varchar(32)  NOT NULL,
   
+  -- Concurrency limits
+  `max_connections`          int(11),
+  `max_connections_per_user` int(11),
+
   PRIMARY KEY (`connection_id`),
   UNIQUE KEY `connection_name_parent` (`connection_name`, `parent_id`),
 

extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-mysql/schema/upgrade/upgrade-pre-0.9.8.sql

@@ -39,3 +39,17 @@ ALTER TABLE guacamole_user ADD COLUMN valid_until DATE;
 --
 
 ALTER TABLE guacamole_user ADD COLUMN timezone VARCHAR(64);
+
+--
+-- Add connection concurrency limits
+--
+
+ALTER TABLE guacamole_connection ADD COLUMN max_connections          INT(11);
+ALTER TABLE guacamole_connection ADD COLUMN max_connections_per_user INT(11);
+
+--
+-- Add connection group concurrency limits
+--
+
+ALTER TABLE guacamole_connection_group ADD COLUMN max_connections          INT(11);
+ALTER TABLE guacamole_connection_group ADD COLUMN max_connections_per_user INT(11);

extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-mysql/src/main/resources/org/glyptodon/guacamole/auth/jdbc/connection/ConnectionMapper.xml

@@ -28,10 +28,12 @@
 
     <!-- Result mapper for connection objects -->
     <resultMap id="ConnectionResultMap" type="org.glyptodon.guacamole.auth.jdbc.connection.ConnectionModel" >
-        <id     column="connection_id"   property="objectID"         jdbcType="INTEGER"/>
+        <id     column="connection_id"            property="objectID"              jdbcType="INTEGER"/>
-        <result column="connection_name" property="name"             jdbcType="VARCHAR"/>
+        <result column="connection_name"          property="name"                  jdbcType="VARCHAR"/>
-        <result column="parent_id"       property="parentIdentifier" jdbcType="INTEGER"/>
+        <result column="parent_id"                property="parentIdentifier"      jdbcType="INTEGER"/>
-        <result column="protocol"        property="protocol"         jdbcType="VARCHAR"/>
+        <result column="protocol"                 property="protocol"              jdbcType="VARCHAR"/>
+        <result column="max_connections"          property="maxConnections"        jdbcType="INTEGER"/>
+        <result column="max_connections_per_user" property="maxConnectionsPerUser" jdbcType="INTEGER"/>
     </resultMap>
 
     <!-- Select all connection identifiers -->
@@ -77,7 +79,9 @@
             connection_id,
             connection_name,
             parent_id,
-            protocol 
+            protocol,
+            max_connections,
+            max_connections_per_user
         FROM guacamole_connection
         WHERE connection_id IN
             <foreach collection="identifiers" item="identifier"
@@ -94,7 +98,9 @@
             guacamole_connection.connection_id,
             connection_name,
             parent_id,
-            protocol 
+            protocol,
+            max_connections,
+            max_connections_per_user
         FROM guacamole_connection
         JOIN guacamole_connection_permission ON guacamole_connection_permission.connection_id = guacamole_connection.connection_id
         WHERE guacamole_connection.connection_id IN
@@ -114,7 +120,9 @@
             connection_id,
             connection_name,
             parent_id,
-            protocol 
+            protocol,
+            max_connections,
+            max_connections_per_user
         FROM guacamole_connection
         WHERE 
             <if test="parentIdentifier != null">parent_id = #{parentIdentifier,jdbcType=VARCHAR}</if>
@@ -136,12 +144,16 @@
         INSERT INTO guacamole_connection (
             connection_name,
             parent_id,
-            protocol 
+            protocol,
+            max_connections,
+            max_connections_per_user
         )
         VALUES (
             #{object.name,jdbcType=VARCHAR},
             #{object.parentIdentifier,jdbcType=VARCHAR},
-            #{object.protocol,jdbcType=VARCHAR}
+            #{object.protocol,jdbcType=VARCHAR},
+            #{object.maxConnections,jdbcType=INTEGER},
+            #{object.maxConnectionsPerUser,jdbcType=INTEGER}
         )
 
     </insert>
@@ -149,9 +161,11 @@
     <!-- Update single connection -->
     <update id="update" parameterType="org.glyptodon.guacamole.auth.jdbc.connection.ConnectionModel">
         UPDATE guacamole_connection
-        SET connection_name = #{object.name,jdbcType=VARCHAR},
+        SET connection_name          = #{object.name,jdbcType=VARCHAR},
-            parent_id       = #{object.parentIdentifier,jdbcType=VARCHAR},
+            parent_id                = #{object.parentIdentifier,jdbcType=VARCHAR},
-            protocol        = #{object.protocol,jdbcType=VARCHAR}
+            protocol                 = #{object.protocol,jdbcType=VARCHAR},
+            max_connections          = #{object.maxConnections,jdbcType=INTEGER},
+            max_connections_per_user = #{object.maxConnectionsPerUser,jdbcType=INTEGER}
         WHERE connection_id = #{object.objectID,jdbcType=INTEGER}
     </update>
 

extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-mysql/src/main/resources/org/glyptodon/guacamole/auth/jdbc/connectiongroup/ConnectionGroupMapper.xml

@@ -28,11 +28,13 @@
 
     <!-- Result mapper for connection objects -->
     <resultMap id="ConnectionGroupResultMap" type="org.glyptodon.guacamole.auth.jdbc.connectiongroup.ConnectionGroupModel" >
-        <id     column="connection_group_id"   property="objectID"         jdbcType="INTEGER"/>
+        <id     column="connection_group_id"      property="objectID"              jdbcType="INTEGER"/>
-        <result column="connection_group_name" property="name"             jdbcType="VARCHAR"/>
+        <result column="connection_group_name"    property="name"                  jdbcType="VARCHAR"/>
-        <result column="parent_id"             property="parentIdentifier" jdbcType="INTEGER"/>
+        <result column="parent_id"                property="parentIdentifier"      jdbcType="INTEGER"/>
-        <result column="type"                  property="type"             jdbcType="VARCHAR"
+        <result column="type"                     property="type"                  jdbcType="VARCHAR"
                 javaType="org.glyptodon.guacamole.net.auth.ConnectionGroup$Type"/>
+        <result column="max_connections"          property="maxConnections"        jdbcType="INTEGER"/>
+        <result column="max_connections_per_user" property="maxConnectionsPerUser" jdbcType="INTEGER"/>
     </resultMap>
 
     <!-- Select all connection group identifiers -->
@@ -78,7 +80,9 @@
             connection_group_id,
             connection_group_name,
             parent_id,
-            type
+            type,
+            max_connections,
+            max_connections_per_user
         FROM guacamole_connection_group
         WHERE connection_group_id IN
             <foreach collection="identifiers" item="identifier"
@@ -95,7 +99,9 @@
             guacamole_connection_group.connection_group_id,
             connection_group_name,
             parent_id,
-            type 
+            type,
+            max_connections,
+            max_connections_per_user
         FROM guacamole_connection_group
         JOIN guacamole_connection_group_permission ON guacamole_connection_group_permission.connection_group_id = guacamole_connection_group.connection_group_id
         WHERE guacamole_connection_group.connection_group_id IN
@@ -115,7 +121,9 @@
             connection_group_id,
             connection_group_name,
             parent_id,
-            type
+            type,
+            max_connections,
+            max_connections_per_user
         FROM guacamole_connection_group
         WHERE 
             <if test="parentIdentifier != null">parent_id = #{parentIdentifier,jdbcType=VARCHAR}</if>
@@ -137,12 +145,16 @@
         INSERT INTO guacamole_connection_group (
             connection_group_name,
             parent_id,
-            type
+            type,
+            max_connections,
+            max_connections_per_user
         )
         VALUES (
             #{object.name,jdbcType=VARCHAR},
             #{object.parentIdentifier,jdbcType=VARCHAR},
-            #{object.type,jdbcType=VARCHAR}
+            #{object.type,jdbcType=VARCHAR},
+            #{object.maxConnections,jdbcType=INTEGER},
+            #{object.maxConnectionsPerUser,jdbcType=INTEGER}
         )
 
     </insert>
@@ -150,9 +162,11 @@
     <!-- Update single connection group -->
     <update id="update" parameterType="org.glyptodon.guacamole.auth.jdbc.connectiongroup.ConnectionGroupModel">
         UPDATE guacamole_connection_group
-        SET connection_group_name = #{object.name,jdbcType=VARCHAR},
+        SET connection_group_name    = #{object.name,jdbcType=VARCHAR},
-            parent_id             = #{object.parentIdentifier,jdbcType=VARCHAR},
+            parent_id                = #{object.parentIdentifier,jdbcType=VARCHAR},
-            type                  = #{object.type,jdbcType=VARCHAR}
+            type                     = #{object.type,jdbcType=VARCHAR},
+            max_connections          = #{object.maxConnections,jdbcType=INTEGER},
+            max_connections_per_user = #{object.maxConnectionsPerUser,jdbcType=INTEGER}
         WHERE connection_group_id = #{object.objectID,jdbcType=INTEGER}
     </update>
 

extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-postgresql/schema/001-create-schema.sql

@@ -63,6 +63,10 @@ CREATE TABLE guacamole_connection_group (
   type                  guacamole_connection_group_type
                         NOT NULL DEFAULT 'ORGANIZATIONAL',
 
+  -- Concurrency limits
+  max_connections          integer,
+  max_connections_per_user integer,
+
   PRIMARY KEY (connection_group_id),
 
   CONSTRAINT connection_group_name_parent
@@ -90,6 +94,10 @@ CREATE TABLE guacamole_connection (
   parent_id           integer,
   protocol            varchar(32)  NOT NULL,
   
+  -- Concurrency limits
+  max_connections          integer,
+  max_connections_per_user integer,
+
   PRIMARY KEY (connection_id),
 
   CONSTRAINT connection_name_parent

extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-postgresql/schema/upgrade/upgrade-pre-0.9.8.sql

@@ -39,3 +39,17 @@ ALTER TABLE guacamole_user ADD COLUMN valid_until date;
 --
 
 ALTER TABLE guacamole_user ADD COLUMN timezone varchar(64);
+
+--
+-- Add connection concurrency limits
+--
+
+ALTER TABLE guacamole_connection ADD COLUMN max_connections          integer;
+ALTER TABLE guacamole_connection ADD COLUMN max_connections_per_user integer;
+
+--
+-- Add connection group concurrency limits
+--
+
+ALTER TABLE guacamole_connection_group ADD COLUMN max_connections          integer;
+ALTER TABLE guacamole_connection_group ADD COLUMN max_connections_per_user integer;

extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-postgresql/src/main/resources/org/glyptodon/guacamole/auth/jdbc/connection/ConnectionMapper.xml

@@ -28,10 +28,12 @@
 
     <!-- Result mapper for connection objects -->
     <resultMap id="ConnectionResultMap" type="org.glyptodon.guacamole.auth.jdbc.connection.ConnectionModel" >
-        <id     column="connection_id"   property="objectID"         jdbcType="INTEGER"/>
+        <id     column="connection_id"            property="objectID"              jdbcType="INTEGER"/>
-        <result column="connection_name" property="name"             jdbcType="VARCHAR"/>
+        <result column="connection_name"          property="name"                  jdbcType="VARCHAR"/>
-        <result column="parent_id"       property="parentIdentifier" jdbcType="INTEGER"/>
+        <result column="parent_id"                property="parentIdentifier"      jdbcType="INTEGER"/>
-        <result column="protocol"        property="protocol"         jdbcType="VARCHAR"/>
+        <result column="protocol"                 property="protocol"              jdbcType="VARCHAR"/>
+        <result column="max_connections"          property="maxConnections"        jdbcType="INTEGER"/>
+        <result column="max_connections_per_user" property="maxConnectionsPerUser" jdbcType="INTEGER"/>
     </resultMap>
 
     <!-- Select all connection identifiers -->
@@ -77,7 +79,9 @@
             connection_id,
             connection_name,
             parent_id,
-            protocol 
+            protocol,
+            max_connections,
+            max_connections_per_user
         FROM guacamole_connection
         WHERE connection_id IN
             <foreach collection="identifiers" item="identifier"
@@ -94,7 +98,9 @@
             guacamole_connection.connection_id,
             connection_name,
             parent_id,
-            protocol 
+            protocol,
+            max_connections,
+            max_connections_per_user
         FROM guacamole_connection
         JOIN guacamole_connection_permission ON guacamole_connection_permission.connection_id = guacamole_connection.connection_id
         WHERE guacamole_connection.connection_id IN
@@ -114,7 +120,9 @@
             connection_id,
             connection_name,
             parent_id,
-            protocol 
+            protocol,
+            max_connections,
+            max_connections_per_user
         FROM guacamole_connection
         WHERE 
             <if test="parentIdentifier != null">parent_id = #{parentIdentifier,jdbcType=INTEGER}::integer</if>
@@ -136,12 +144,16 @@
         INSERT INTO guacamole_connection (
             connection_name,
             parent_id,
-            protocol 
+            protocol,
+            max_connections,
+            max_connections_per_user
         )
         VALUES (
             #{object.name,jdbcType=VARCHAR},
             #{object.parentIdentifier,jdbcType=INTEGER}::integer,
-            #{object.protocol,jdbcType=VARCHAR}
+            #{object.protocol,jdbcType=VARCHAR},
+            #{object.maxConnections,jdbcType=INTEGER},
+            #{object.maxConnectionsPerUser,jdbcType=INTEGER}
         )
 
     </insert>
@@ -149,9 +161,11 @@
     <!-- Update single connection -->
     <update id="update" parameterType="org.glyptodon.guacamole.auth.jdbc.connection.ConnectionModel">
         UPDATE guacamole_connection
-        SET connection_name = #{object.name,jdbcType=VARCHAR},
+        SET connection_name          = #{object.name,jdbcType=VARCHAR},
-            parent_id       = #{object.parentIdentifier,jdbcType=INTEGER}::integer,
+            parent_id                = #{object.parentIdentifier,jdbcType=INTEGER}::integer,
-            protocol        = #{object.protocol,jdbcType=VARCHAR}
+            protocol                 = #{object.protocol,jdbcType=VARCHAR},
+            max_connections          = #{object.maxConnections,jdbcType=INTEGER},
+            max_connections_per_user = #{object.maxConnectionsPerUser,jdbcType=INTEGER}
         WHERE connection_id = #{object.objectID,jdbcType=INTEGER}::integer
     </update>
 

extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-postgresql/src/main/resources/org/glyptodon/guacamole/auth/jdbc/connectiongroup/ConnectionGroupMapper.xml

@@ -28,11 +28,13 @@
 
     <!-- Result mapper for connection objects -->
     <resultMap id="ConnectionGroupResultMap" type="org.glyptodon.guacamole.auth.jdbc.connectiongroup.ConnectionGroupModel" >
-        <id     column="connection_group_id"   property="objectID"         jdbcType="INTEGER"/>
+        <id     column="connection_group_id"      property="objectID"              jdbcType="INTEGER"/>
-        <result column="connection_group_name" property="name"             jdbcType="VARCHAR"/>
+        <result column="connection_group_name"    property="name"                  jdbcType="VARCHAR"/>
-        <result column="parent_id"             property="parentIdentifier" jdbcType="INTEGER"/>
+        <result column="parent_id"                property="parentIdentifier"      jdbcType="INTEGER"/>
-        <result column="type"                  property="type"             jdbcType="VARCHAR"
+        <result column="type"                     property="type"                  jdbcType="VARCHAR"
                 javaType="org.glyptodon.guacamole.net.auth.ConnectionGroup$Type"/>
+        <result column="max_connections"          property="maxConnections"        jdbcType="INTEGER"/>
+        <result column="max_connections_per_user" property="maxConnectionsPerUser" jdbcType="INTEGER"/>
     </resultMap>
 
     <!-- Select all connection group identifiers -->
@@ -78,7 +80,9 @@
             connection_group_id,
             connection_group_name,
             parent_id,
-            type
+            type,
+            max_connections,
+            max_connections_per_user
         FROM guacamole_connection_group
         WHERE connection_group_id IN
             <foreach collection="identifiers" item="identifier"
@@ -95,7 +99,9 @@
             guacamole_connection_group.connection_group_id,
             connection_group_name,
             parent_id,
-            type 
+            type,
+            max_connections,
+            max_connections_per_user
         FROM guacamole_connection_group
         JOIN guacamole_connection_group_permission ON guacamole_connection_group_permission.connection_group_id = guacamole_connection_group.connection_group_id
         WHERE guacamole_connection_group.connection_group_id IN
@@ -115,7 +121,9 @@
             connection_group_id,
             connection_group_name,
             parent_id,
-            type
+            type,
+            max_connections,
+            max_connections_per_user
         FROM guacamole_connection_group
         WHERE 
             <if test="parentIdentifier != null">parent_id = #{parentIdentifier,jdbcType=INTEGER}::integer</if>
@@ -137,12 +145,16 @@
         INSERT INTO guacamole_connection_group (
             connection_group_name,
             parent_id,
-            type
+            type,
+            max_connections,
+            max_connections_per_user
         )
         VALUES (
             #{object.name,jdbcType=VARCHAR},
             #{object.parentIdentifier,jdbcType=INTEGER}::integer,
-            #{object.type,jdbcType=VARCHAR}::guacamole_connection_group_type
+            #{object.type,jdbcType=VARCHAR}::guacamole_connection_group_type,
+            #{object.maxConnections,jdbcType=INTEGER},
+            #{object.maxConnectionsPerUser,jdbcType=INTEGER}
         )
 
     </insert>
@@ -150,9 +162,11 @@
     <!-- Update single connection group -->
     <update id="update" parameterType="org.glyptodon.guacamole.auth.jdbc.connectiongroup.ConnectionGroupModel">
         UPDATE guacamole_connection_group
-        SET connection_group_name = #{object.name,jdbcType=VARCHAR},
+        SET connection_group_name    = #{object.name,jdbcType=VARCHAR},
-            parent_id             = #{object.parentIdentifier,jdbcType=INTEGER}::integer,
+            parent_id                = #{object.parentIdentifier,jdbcType=INTEGER}::integer,
-            type                  = #{object.type,jdbcType=VARCHAR}::guacamole_connection_group_type
+            type                     = #{object.type,jdbcType=VARCHAR}::guacamole_connection_group_type,
+            max_connections          = #{object.maxConnections,jdbcType=INTEGER},
+            max_connections_per_user = #{object.maxConnectionsPerUser,jdbcType=INTEGER}
         WHERE connection_group_id = #{object.objectID,jdbcType=INTEGER}::integer
     </update>
 

guacamole-ext/src/main/java/org/glyptodon/guacamole/form/DateField.java

@@ -22,6 +22,11 @@
 
 package org.glyptodon.guacamole.form;
 
+import java.text.DateFormat;
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.util.Date;
+
 /**
  * Represents a date field. The field may contain only date values which
  * conform to a standard pattern, defined by DateField.FORMAT.
@@ -45,4 +50,48 @@ public class DateField extends Field {
         super(name, Field.Type.DATE);
     }
 
+    /**
+     * Converts the given date into a string which follows the format used by
+     * date fields.
+     *
+     * @param date
+     *     The date value to format, which may be null.
+     *
+     * @return
+     *     The formatted date, or null if the provided time was null.
+     */
+    public static String format(Date date) {
+        DateFormat dateFormat = new SimpleDateFormat(DateField.FORMAT);
+        return date == null ? null : dateFormat.format(date);
+    }
+
+    /**
+     * Parses the given string into a corresponding date. The string must
+     * follow the standard format used by date fields, as defined by FORMAT
+     * and as would be produced by format().
+     *
+     * @param dateString
+     *     The date string to parse, which may be null.
+     *
+     * @return
+     *     The date corresponding to the given date string, or null if the
+     *     provided date string was null or blank.
+     *
+     * @throws ParseException
+     *     If the given date string does not conform to the standard format
+     *     used by date fields.
+     */
+    public static Date parse(String dateString)
+            throws ParseException {
+
+        // Return null if no date provided
+        if (dateString == null || dateString.isEmpty())
+            return null;
+
+        // Parse date according to format
+        DateFormat dateFormat = new SimpleDateFormat(DateField.FORMAT);
+        return dateFormat.parse(dateString);
+
+    }
+
 }

guacamole-ext/src/main/java/org/glyptodon/guacamole/form/NumericField.java

@@ -39,4 +39,50 @@ public class NumericField extends Field {
         super(name, Field.Type.NUMERIC);
     }
 
+    /**
+     * Formats the given integer in the format required by a numeric field.
+     *
+     * @param i
+     *     The integer to format, which may be null.
+     *
+     * @return
+     *     A string representation of the given integer, or null if the given
+     *     integer was null.
+     */
+    public static String format(Integer i) {
+
+        // Return null if no value provided
+        if (i == null)
+            return null;
+
+        // Convert to string
+        return i.toString();
+
+    }
+
+    /**
+     * Parses the given string as an integer, where the given string is in the
+     * format required by a numeric field.
+     *
+     * @param str
+     *     The string to parse as an integer, which may be null.
+     *
+     * @return
+     *     The integer representation of the given string, or null if the given
+     *     string was null.
+     *
+     * @throws NumberFormatException
+     *     If the given string is not in a parseable format.
+     */
+    public static Integer parse(String str) throws NumberFormatException {
+
+        // Return null if no value provided
+        if (str == null || str.isEmpty())
+            return null;
+
+        // Parse as integer
+        return new Integer(str);
+
+    }
+
 }

guacamole-ext/src/main/java/org/glyptodon/guacamole/form/TimeField.java

@@ -22,6 +22,11 @@
 
 package org.glyptodon.guacamole.form;
 
+import java.text.DateFormat;
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.util.Date;
+
 /**
  * Represents a time field. The field may contain only time values which
  * conform to a standard pattern, defined by TimeField.FORMAT.
@@ -45,4 +50,48 @@ public class TimeField extends Field {
         super(name, Field.Type.TIME);
     }
 
+    /**
+     * Parses the given string into a corresponding time. The string must
+     * follow the standard format used by time fields, as defined by
+     * FORMAT and as would be produced by format().
+     *
+     * @param timeString
+     *     The time string to parse, which may be null.
+     *
+     * @return
+     *     The time corresponding to the given time string, or null if the
+     *     provided time string was null or blank.
+     *
+     * @throws ParseException
+     *     If the given time string does not conform to the standard format
+     *     used by time fields.
+     */
+    public static Date parse(String timeString)
+            throws ParseException {
+
+        // Return null if no time provided
+        if (timeString == null || timeString.isEmpty())
+            return null;
+
+        // Parse time according to format
+        DateFormat timeFormat = new SimpleDateFormat(TimeField.FORMAT);
+        return timeFormat.parse(timeString);
+
+    }
+
+    /**
+     * Converts the given time into a string which follows the format used by
+     * time fields.
+     *
+     * @param time
+     *     The time value to format, which may be null.
+     *
+     * @return
+     *     The formatted time, or null if the provided time was null.
+     */
+    public static String format(Date time) {
+        DateFormat timeFormat = new SimpleDateFormat(TimeField.FORMAT);
+        return time == null ? null : timeFormat.format(time);
+    }
+
 }

guacamole-ext/src/main/java/org/glyptodon/guacamole/form/TimeZoneField.java

@@ -40,4 +40,27 @@ public class TimeZoneField extends Field {
         super(name, Field.Type.TIMEZONE);
     }
 
+    /**
+     * Parses the given string into a time zone ID string. As these strings are
+     * equivalent, the only transformation currently performed by this function
+     * is to ensure that a blank time zone string is parsed into null.
+     *
+     * @param timeZone
+     *     The time zone string to parse, which may be null.
+     *
+     * @return
+     *     The ID of the time zone corresponding to the given string, or null
+     *     if the given time zone string was null or blank.
+     */
+    public static String parse(String timeZone) {
+
+        // Return null if no time zone provided
+        if (timeZone == null || timeZone.isEmpty())
+            return null;
+
+        // Otherwise, assume time zone is valid
+        return timeZone;
+
+    }
+
 }

guacamole/src/main/webapp/app/form/controllers/numberFieldController.js

@@ -34,7 +34,7 @@ angular.module('form').controller('numberFieldController', ['$scope',
 
     // Update string value in model when typed value is changed
     $scope.$watch('typedValue', function typedValueChanged(typedValue) {
-        $scope.model = (typedValue ? typedValue.toString() : '');
+        $scope.model = ((typedValue || typedValue === 0) ? typedValue.toString() : '');
     });
 
 }]);