GUACAMOLE-1006: Merge support for reading any property value as a Collection.

extensions/guacamole-auth-json/src/main/java/org/apache/guacamole/auth/json/ConfigurationService.java

@@ -25,7 +25,7 @@ import java.util.Collections;
 import org.apache.guacamole.GuacamoleException;
 import org.apache.guacamole.environment.Environment;
 import org.apache.guacamole.properties.ByteArrayProperty;
-import org.apache.guacamole.properties.StringListProperty;
+import org.apache.guacamole.properties.StringGuacamoleProperty;
 
 /**
  * Service for retrieving configuration information regarding the JSON
@@ -56,7 +56,7 @@ public class ConfigurationService {
      * be allowed to perform authentication. If not specified, ALL address will
      * be allowed.
      */
-    private static final StringListProperty JSON_TRUSTED_NETWORKS = new StringListProperty() {
+    private static final StringGuacamoleProperty JSON_TRUSTED_NETWORKS = new StringGuacamoleProperty() {
 
         @Override
         public String getName() {
@@ -95,7 +95,7 @@ public class ConfigurationService {
      *     If guacamole.properties cannot be parsed.
      */
     public Collection<String> getTrustedNetworks() throws GuacamoleException {
-        return environment.getProperty(JSON_TRUSTED_NETWORKS, Collections.<String>emptyList());
+        return environment.getPropertyCollection(JSON_TRUSTED_NETWORKS, Collections.<String>emptyList());
     }
 
 }

extensions/guacamole-auth-ldap/src/main/java/org/apache/guacamole/auth/ldap/AuthenticationProviderService.java

@@ -401,7 +401,7 @@ public class AuthenticationProviderService {
             throws GuacamoleException {
 
         // Get attributes from configuration information
-        List<String> attrList = config.getAttributes();
+        Collection<String> attrList = config.getAttributes();
 
         // If there are no attributes there is no reason to search LDAP
         if (attrList.isEmpty())

extensions/guacamole-auth-ldap/src/main/java/org/apache/guacamole/auth/ldap/ConnectedLDAPConfiguration.java

@@ -19,6 +19,7 @@
 
 package org.apache.guacamole.auth.ldap;
 
+import java.util.Collection;
 import java.util.List;
 import org.apache.directory.api.ldap.model.filter.ExprNode;
 import org.apache.directory.api.ldap.model.message.AliasDerefMode;
@@ -124,7 +125,7 @@ public class ConnectedLDAPConfiguration implements LDAPConfiguration, AutoClosea
     }
 
     @Override
-    public List<String> getUsernameAttributes() throws GuacamoleException {
+    public Collection<String> getUsernameAttributes() throws GuacamoleException {
         return config.getUsernameAttributes();
     }
 
@@ -139,7 +140,7 @@ public class ConnectedLDAPConfiguration implements LDAPConfiguration, AutoClosea
     }
 
     @Override
-    public List<String> getGroupNameAttributes() throws GuacamoleException {
+    public Collection<String> getGroupNameAttributes() throws GuacamoleException {
         return config.getGroupNameAttributes();
     }
 
@@ -209,7 +210,7 @@ public class ConnectedLDAPConfiguration implements LDAPConfiguration, AutoClosea
     }
 
     @Override
-    public List<String> getAttributes() throws GuacamoleException {
+    public Collection<String> getAttributes() throws GuacamoleException {
         return config.getAttributes();
     }
 

extensions/guacamole-auth-ldap/src/main/java/org/apache/guacamole/auth/ldap/conf/EnvironmentLDAPConfiguration.java

@@ -19,7 +19,7 @@
 
 package org.apache.guacamole.auth.ldap.conf;
 
-import java.util.List;
+import java.util.Collection;
 import org.apache.directory.api.ldap.model.filter.ExprNode;
 import org.apache.directory.api.ldap.model.message.AliasDerefMode;
 import org.apache.directory.api.ldap.model.name.Dn;
@@ -75,8 +75,8 @@ public class EnvironmentLDAPConfiguration implements LDAPConfiguration {
     }
 
     @Override
-    public List<String> getUsernameAttributes() throws GuacamoleException {
+    public Collection<String> getUsernameAttributes() throws GuacamoleException {
-        return environment.getProperty(
+        return environment.getPropertyCollection(
             LDAPGuacamoleProperties.LDAP_USERNAME_ATTRIBUTE,
             DEFAULT.getUsernameAttributes()
         );
@@ -98,8 +98,8 @@ public class EnvironmentLDAPConfiguration implements LDAPConfiguration {
     }
 
     @Override
-    public List<String> getGroupNameAttributes() throws GuacamoleException {
+    public Collection<String> getGroupNameAttributes() throws GuacamoleException {
-        return environment.getProperty(
+        return environment.getPropertyCollection(
             LDAPGuacamoleProperties.LDAP_GROUP_NAME_ATTRIBUTE,
             DEFAULT.getGroupNameAttributes()
         );
@@ -210,8 +210,8 @@ public class EnvironmentLDAPConfiguration implements LDAPConfiguration {
     }
 
     @Override
-    public List<String> getAttributes() throws GuacamoleException {
+    public Collection<String> getAttributes() throws GuacamoleException {
-        return environment.getProperty(
+        return environment.getPropertyCollection(
             LDAPGuacamoleProperties.LDAP_USER_ATTRIBUTES,
             DEFAULT.getAttributes()
         );

extensions/guacamole-auth-ldap/src/main/java/org/apache/guacamole/auth/ldap/conf/JacksonLDAPConfiguration.java

@@ -22,6 +22,7 @@ package org.apache.guacamole.auth.ldap.conf;
 import com.fasterxml.jackson.annotation.JsonFormat;
 import static com.fasterxml.jackson.annotation.JsonFormat.Feature.ACCEPT_SINGLE_VALUE_AS_ARRAY;
 import com.fasterxml.jackson.annotation.JsonProperty;
+import java.util.Collection;
 import java.util.List;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -331,7 +332,7 @@ public class JacksonLDAPConfiguration implements LDAPConfiguration {
     }
 
     @Override
-    public List<String> getUsernameAttributes() throws GuacamoleException {
+    public Collection<String> getUsernameAttributes() throws GuacamoleException {
         return withDefault(usernameAttributes, defaultConfig::getUsernameAttributes);
     }
 
@@ -348,7 +349,7 @@ public class JacksonLDAPConfiguration implements LDAPConfiguration {
     }
 
     @Override
-    public List<String> getGroupNameAttributes() throws GuacamoleException {
+    public Collection<String> getGroupNameAttributes() throws GuacamoleException {
         return withDefault(groupNameAttributes, defaultConfig::getGroupNameAttributes);
     }
 
@@ -424,7 +425,7 @@ public class JacksonLDAPConfiguration implements LDAPConfiguration {
     }
 
     @Override
-    public List<String> getAttributes() throws GuacamoleException {
+    public Collection<String> getAttributes() throws GuacamoleException {
         return withDefault(userAttributes, defaultConfig::getAttributes);
     }
     

extensions/guacamole-auth-ldap/src/main/java/org/apache/guacamole/auth/ldap/conf/LDAPConfiguration.java

@@ -19,6 +19,7 @@
 
 package org.apache.guacamole.auth.ldap.conf;
 
+import java.util.Collection;
 import java.util.List;
 import org.apache.directory.api.ldap.model.filter.ExprNode;
 import org.apache.directory.api.ldap.model.message.AliasDerefMode;
@@ -84,7 +85,7 @@ public interface LDAPConfiguration {
      * @throws GuacamoleException
      *     If the username attributes cannot be retrieved.
      */
-    List<String> getUsernameAttributes() throws GuacamoleException;
+    Collection<String> getUsernameAttributes() throws GuacamoleException;
 
     /**
      * Returns the base DN under which all Guacamole users will be stored
@@ -125,7 +126,7 @@ public interface LDAPConfiguration {
      * @throws GuacamoleException
      *     If the group name attributes cannot be retrieved.
      */
-    List<String> getGroupNameAttributes() throws GuacamoleException;
+    Collection<String> getGroupNameAttributes() throws GuacamoleException;
 
     /**
      * Returns the base DN under which all Guacamole role based access control
@@ -305,7 +306,7 @@ public interface LDAPConfiguration {
      *     If the names of the LDAP user attributes to be exposed as parameter
      *     tokens cannot be retrieved.
      */
-    List<String> getAttributes() throws GuacamoleException;
+    Collection<String> getAttributes() throws GuacamoleException;
     
     /**
      * Returns the name of the LDAP attribute used to enumerate members in a

extensions/guacamole-auth-ldap/src/main/java/org/apache/guacamole/auth/ldap/conf/LDAPGuacamoleProperties.java

@@ -84,8 +84,8 @@ public class LDAPGuacamoleProperties {
      * one attribute, and the concatenation of that attribute and the value of
      * LDAP_USER_BASE_DN must equal the user's full DN.
      */
-    public static final StringListProperty LDAP_USERNAME_ATTRIBUTE =
+    public static final StringGuacamoleProperty LDAP_USERNAME_ATTRIBUTE =
-            new StringListProperty() {
+            new StringGuacamoleProperty() {
 
         @Override
         public String getName() { return "ldap-username-attribute"; }
@@ -97,8 +97,8 @@ public class LDAPGuacamoleProperties {
      * attributes must be present within each Guacamole user group's record in
      * the LDAP directory for that group to be visible.
      */
-    public static final StringListProperty LDAP_GROUP_NAME_ATTRIBUTE =
+    public static final StringGuacamoleProperty LDAP_GROUP_NAME_ATTRIBUTE =
-            new StringListProperty() {
+            new StringGuacamoleProperty() {
 
         @Override
         public String getName() { return "ldap-group-name-attribute"; }
@@ -277,8 +277,8 @@ public class LDAPGuacamoleProperties {
      * Custom attribute or attributes to query from Guacamole user's record in
      * the LDAP directory.
      */
-    public static final StringListProperty LDAP_USER_ATTRIBUTES =
+    public static final StringGuacamoleProperty LDAP_USER_ATTRIBUTES =
-            new StringListProperty() {
+            new StringGuacamoleProperty() {
 
         @Override
         public String getName() { return "ldap-user-attributes"; }

extensions/guacamole-auth-ldap/src/main/java/org/apache/guacamole/auth/ldap/conf/StringListProperty.java

@@ -1,62 +0,0 @@
-/*
- * 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.guacamole.auth.ldap.conf;
-
-import java.util.Arrays;
-import java.util.List;
-import java.util.regex.Pattern;
-import org.apache.guacamole.GuacamoleException;
-import org.apache.guacamole.properties.GuacamoleProperty;
-
-/**
- * A GuacamoleProperty whose value is a List of Strings. The string value
- * parsed to produce this list is a comma-delimited list. Duplicate values are
- * ignored, as is any whitespace following delimiters. To maintain
- * compatibility with the behavior of Java properties in general, only
- * whitespace at the beginning of each value is ignored; trailing whitespace
- * becomes part of the value.
- */
-public abstract class StringListProperty implements GuacamoleProperty<List<String>> {
-
-    /**
-     * A pattern which matches against the delimiters between values. This is
-     * currently simply a comma and any following whitespace. Parts of the
-     * input string which match this pattern will not be included in the parsed
-     * result.
-     */
-    private static final Pattern DELIMITER_PATTERN = Pattern.compile(",\\s*");
-
-    @Override
-    public List<String> parseValue(String values) throws GuacamoleException {
-
-        // If no property provided, return null.
-        if (values == null)
-            return null;
-
-        // Split string into a list of individual values
-        List<String> stringValues = Arrays.asList(DELIMITER_PATTERN.split(values));
-        if (stringValues.isEmpty())
-            return null;
-
-        return stringValues;
-
-    }
-
-}

extensions/guacamole-auth-ldap/src/main/java/org/apache/guacamole/auth/ldap/user/UserService.java

@@ -183,7 +183,7 @@ public class UserService {
             throws GuacamoleException {
 
         // Pull username attributes from properties
-        List<String> usernameAttributes = config.getUsernameAttributes();
+        List<String> usernameAttributes = new ArrayList<>(config.getUsernameAttributes());
 
         // We need exactly one base DN to derive the user DN
         if (usernameAttributes.size() != 1) {

extensions/guacamole-auth-quickconnect/src/main/java/org/apache/guacamole/auth/quickconnect/conf/ConfigurationService.java

@@ -20,10 +20,11 @@
 package org.apache.guacamole.auth.quickconnect.conf;
 
 import com.google.inject.Inject;
+import java.util.Collection;
 import java.util.List;
 import org.apache.guacamole.GuacamoleException;
 import org.apache.guacamole.environment.Environment;
-import org.apache.guacamole.properties.StringListProperty;
+import org.apache.guacamole.properties.StringGuacamoleProperty;
 
 /**
  * Configuration options to control the QuickConnect module.
@@ -42,7 +43,7 @@ public class ConfigurationService {
      * the parameters defined in this list.  Defaults to null (all parameters
      * are allowed).
      */
-    public static final StringListProperty QUICKCONNECT_ALLOWED_PARAMETERS = new StringListProperty() {
+    public static final StringGuacamoleProperty QUICKCONNECT_ALLOWED_PARAMETERS = new StringGuacamoleProperty() {
         
         @Override
         public String getName() { return "quickconnect-allowed-parameters"; }
@@ -55,7 +56,7 @@ public class ConfigurationService {
      * except the ones defined in this list.  Defaults to null (all parameters
      * are allowed).
      */
-    public static final StringListProperty QUICKCONNECT_DENIED_PARAMETERS = new StringListProperty() {
+    public static final StringGuacamoleProperty QUICKCONNECT_DENIED_PARAMETERS = new StringGuacamoleProperty() {
         
         @Override
         public String getName() { return "quickconnect-denied-parameters"; }
@@ -74,8 +75,8 @@ public class ConfigurationService {
      * @throws GuacamoleException
      *    If guacamole.properties cannot be parsed.
      */
-    public List<String> getAllowedParameters() throws GuacamoleException {
+    public Collection<String> getAllowedParameters() throws GuacamoleException {
-        return environment.getProperty(QUICKCONNECT_ALLOWED_PARAMETERS);
+        return environment.getPropertyCollection(QUICKCONNECT_ALLOWED_PARAMETERS);
     }
     
     /**
@@ -90,8 +91,8 @@ public class ConfigurationService {
      * @throws GuacamoleException 
      *     If guacamole.properties cannot be parsed.
      */
-    public List<String> getDeniedParameters() throws GuacamoleException {
+    public Collection<String> getDeniedParameters() throws GuacamoleException {
-        return environment.getProperty(QUICKCONNECT_DENIED_PARAMETERS);
+        return environment.getPropertyCollection(QUICKCONNECT_DENIED_PARAMETERS);
     }
     
 }

extensions/guacamole-auth-quickconnect/src/main/java/org/apache/guacamole/auth/quickconnect/utility/QCParser.java

@@ -25,6 +25,7 @@ import java.net.URI;
 import java.net.URISyntaxException;
 import java.net.URLDecoder;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.regex.Matcher;
@@ -60,13 +61,13 @@ public class QCParser {
      * by this parser. If not defined, all parameters will be allowed unless
      * explicitly denied.
      */
-    private final List<String> allowedParams;
+    private final Collection<String> allowedParams;
     
     /**
      * The list of parameters that are explicitly denied from being placed into
      * a configuration by this parser.
      */
-    private final List<String> deniedParams;
+    private final Collection<String> deniedParams;
     
     /**
      * Create a new instance of the QCParser class, with the provided allowed
@@ -81,7 +82,7 @@ public class QCParser {
      *     A list of parameters, if any, that should be explicitly denied from
      *     being placed into a connection configuration.
      */
-    public QCParser(List<String> allowedParams, List<String> deniedParams) {
+    public QCParser(Collection<String> allowedParams, Collection<String> deniedParams) {
         this.allowedParams = allowedParams;
         this.deniedParams = deniedParams;
     }

extensions/guacamole-auth-sso/modules/guacamole-auth-sso-openid/src/main/java/org/apache/guacamole/auth/openid/conf/ConfigurationService.java

@@ -21,13 +21,13 @@ package org.apache.guacamole.auth.openid.conf;
 
 import com.google.inject.Inject;
 import java.net.URI;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import org.apache.guacamole.GuacamoleException;
 import org.apache.guacamole.environment.Environment;
 import org.apache.guacamole.properties.IntegerGuacamoleProperty;
 import org.apache.guacamole.properties.StringGuacamoleProperty;
-import org.apache.guacamole.properties.StringListProperty;
 import org.apache.guacamole.properties.URIGuacamoleProperty;
 
 /**
@@ -138,8 +138,8 @@ public class ConfigurationService {
      * The claims within any valid JWT that should be mapped to
      * the authenticated user's tokens, as configured with guacamole.properties.
      */
-    private static final StringListProperty OPENID_ATTRIBUTES_CLAIM_TYPE =
+    private static final StringGuacamoleProperty OPENID_ATTRIBUTES_CLAIM_TYPE =
-            new StringListProperty() {
+            new StringGuacamoleProperty() {
                 @Override
                 public String getName() { return "openid-attributes-claim-type"; }
             };
@@ -356,8 +356,8 @@ public class ConfigurationService {
      * @throws GuacamoleException
      *     If guacamole.properties cannot be parsed.
      */
-    public List<String> getAttributesClaimType() throws GuacamoleException {
+    public Collection<String> getAttributesClaimType() throws GuacamoleException {
-        return environment.getProperty(OPENID_ATTRIBUTES_CLAIM_TYPE, DEFAULT_ATTRIBUTES_CLAIM_TYPE);
+        return environment.getPropertyCollection(OPENID_ATTRIBUTES_CLAIM_TYPE, DEFAULT_ATTRIBUTES_CLAIM_TYPE);
     }
 
     /**

extensions/guacamole-auth-sso/modules/guacamole-auth-sso-openid/src/main/java/org/apache/guacamole/auth/openid/token/TokenValidationService.java

@@ -20,6 +20,7 @@
 package org.apache.guacamole.auth.openid.token;
 
 import com.google.inject.Inject;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -229,7 +230,7 @@ public class TokenValidationService {
      *     If guacamole.properties could not be parsed.
      */
     public Map<String, String> processAttributes(JwtClaims claims) throws GuacamoleException {
-        List<String> attributesClaim = confService.getAttributesClaimType();
+        Collection<String> attributesClaim = confService.getAttributesClaimType();
 
         if (claims != null && !attributesClaim.isEmpty()) {
             try {

extensions/guacamole-auth-sso/modules/guacamole-auth-sso-ssl/src/main/java/org/apache/guacamole/auth/ssl/SSLClientAuthenticationResource.java

@@ -26,6 +26,7 @@ import java.io.UnsupportedEncodingException;
 import java.net.URI;
 import java.net.URLDecoder;
 import java.nio.charset.StandardCharsets;
+import java.util.Collection;
 import java.util.Date;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
@@ -214,7 +215,7 @@ public class SSLClientAuthenticationResource extends SSOResource {
 
         // Verify that the username is specified with one of the allowed
         // attributes
-        List<String> usernameAttributes = confService.getSubjectUsernameAttributes();
+        Collection<String> usernameAttributes = confService.getSubjectUsernameAttributes();
         if (usernameAttributes != null && !usernameAttributes.stream().anyMatch(nameRdn.getType()::equalsIgnoreCase))
             throw new GuacamoleClientException("Subject DN \"" + dn + "\" "
                     + "does not contain an acceptable username attribute.");

extensions/guacamole-auth-sso/modules/guacamole-auth-sso-ssl/src/main/java/org/apache/guacamole/auth/ssl/conf/ConfigurationService.java

@@ -22,7 +22,7 @@ package org.apache.guacamole.auth.ssl.conf;
 import com.google.inject.Inject;
 import java.net.URI;
 import java.net.URISyntaxException;
-import java.util.List;
+import java.util.Collection;
 import javax.naming.ldap.LdapName;
 import javax.ws.rs.core.UriBuilder;
 import org.apache.guacamole.GuacamoleException;
@@ -30,7 +30,6 @@ import org.apache.guacamole.GuacamoleServerException;
 import org.apache.guacamole.environment.Environment;
 import org.apache.guacamole.properties.IntegerGuacamoleProperty;
 import org.apache.guacamole.properties.StringGuacamoleProperty;
-import org.apache.guacamole.properties.StringListProperty;
 import org.apache.guacamole.properties.URIGuacamoleProperty;
 
 /**
@@ -146,8 +145,8 @@ public class ConfigurationService {
      * one of these attributes, the certificate will be rejected. By default,
      * any attribute is accepted.
      */
-    private static final StringListProperty SSL_SUBJECT_USERNAME_ATTRIBUTE =
+    private static final StringGuacamoleProperty SSL_SUBJECT_USERNAME_ATTRIBUTE =
-            new StringListProperty () {
+            new StringGuacamoleProperty () {
 
         @Override
         public String getName() { return "ssl-subject-username-attribute"; }
@@ -433,8 +432,8 @@ public class ConfigurationService {
      * @throws GuacamoleException
      *     If the configured set of username attributes cannot be read.
      */
-    public List<String> getSubjectUsernameAttributes() throws GuacamoleException {
+    public Collection<String> getSubjectUsernameAttributes() throws GuacamoleException {
-        return environment.getProperty(SSL_SUBJECT_USERNAME_ATTRIBUTE);
+        return environment.getPropertyCollection(SSL_SUBJECT_USERNAME_ATTRIBUTE);
     }
 
 }

guacamole-ext/src/main/java/org/apache/guacamole/environment/DelegatingEnvironment.java

@@ -20,6 +20,7 @@
 package org.apache.guacamole.environment;
 
 import java.io.File;
+import java.util.Collection;
 import java.util.Map;
 import org.apache.guacamole.GuacamoleException;
 import org.apache.guacamole.net.auth.GuacamoleProxyConfiguration;
@@ -74,11 +75,35 @@ public class DelegatingEnvironment implements Environment {
         return environment.getProperty(property, defaultValue);
     }
     
+    @Override
+    public <Type> Collection<Type> getPropertyCollection(GuacamoleProperty<Type> property)
+            throws GuacamoleException {
+        return environment.getPropertyCollection(property);
+    }
+    
+    @Override
+    public <Type> Collection<Type> getPropertyCollection(GuacamoleProperty<Type> property,
+            Type defaultValue) throws GuacamoleException {
+        return environment.getPropertyCollection(property, defaultValue);
+    }
+    
+    @Override
+    public <Type> Collection<Type> getPropertyCollection(GuacamoleProperty<Type> property,
+            Collection<Type> defaultValue) throws GuacamoleException {
+        return environment.getPropertyCollection(property, defaultValue);
+    }
+
     @Override
     public <Type> Type getRequiredProperty(GuacamoleProperty<Type> property) throws GuacamoleException {
         return environment.getRequiredProperty(property);
     }
     
+    @Override
+    public <Type> Collection<Type> getRequiredPropertyCollection(GuacamoleProperty<Type> property)
+            throws GuacamoleException {
+        return environment.getRequiredPropertyCollection(property);
+    }
+
     @Override
     public GuacamoleProxyConfiguration getDefaultGuacamoleProxyConfiguration() throws GuacamoleException {
         return environment.getDefaultGuacamoleProxyConfiguration();

guacamole-ext/src/main/java/org/apache/guacamole/environment/Environment.java

@@ -21,6 +21,8 @@ package org.apache.guacamole.environment;
 
 import org.apache.guacamole.properties.GuacamoleProperties;
 import java.io.File;
+import java.util.Collection;
+import java.util.Collections;
 import java.util.Map;
 import org.apache.guacamole.GuacamoleException;
 import org.apache.guacamole.GuacamoleUnsupportedException;
@@ -102,13 +104,18 @@ public interface Environment {
      * Given a GuacamoleProperty, parses and returns the value set for that
      * property in guacamole.properties, if any.
      *
-     * @param <Type> The type that the given property is parsed into.
+     * @param <Type>
-     * @param property The property to read from guacamole.properties.
+     *     The type that the given property is parsed into.
-     * @return The parsed value of the property as read from
+     * 
-     *         guacamole.properties.
+     * @param property
-     * @throws GuacamoleException If an error occurs while parsing the value
+     *     The property to read from guacamole.properties.
-     *                            for the given property in
+     * 
-     *                            guacamole.properties.
+     * @return
+     *     The parsed value of the property as read from guacamole.properties.
+     * 
+     * @throws GuacamoleException
+     *     If an error occurs while parsing the value for the given property in
+     *     guacamole.properties.
      */
     public <Type> Type getProperty(GuacamoleProperty<Type> property)
             throws GuacamoleException;
@@ -118,20 +125,161 @@ public interface Environment {
      * property in guacamole.properties, if any. If no value is found, the
      * provided default value is returned.
      *
-     * @param <Type> The type that the given property is parsed into.
+     * @param <Type>
-     * @param property The property to read from guacamole.properties.
+     *     The type that the given property is parsed into.
-     * @param defaultValue The value to return if no value was given in
+     * 
-     *                     guacamole.properties.
+     * @param property
-     * @return The parsed value of the property as read from
+     *     The property to read from guacamole.properties.
-     *         guacamole.properties, or the provided default value if no value
+     * 
-     *         was found.
+     * @param defaultValue
-     * @throws GuacamoleException If an error occurs while parsing the value
+     *     The value to return if no value was given in guacamole.properties.
-     *                            for the given property in
+     * 
-     *                            guacamole.properties.
+     * @return
+     *     The parsed value of the property as read from guacamole.properties,
+     *     or the provided default value if no value was found.
+     * 
+     * @throws GuacamoleException
+     *     If an error occurs while parsing the value for the given property in
+     *     guacamole.properties.
      */
     public <Type> Type getProperty(GuacamoleProperty<Type> property,
             Type defaultValue) throws GuacamoleException;
 
+    /**
+     * Given a GuacamoleProperty, parses and returns a sorted Collection of the
+     * value set for that property in guacamole.properties, if any. The
+     * implementation of parsing and returning a collection of multiple
+     * values is up to the individual property implementations, and not all
+     * implementations will support reading and returning multiple values.
+     *
+     * @param <Type>
+     *     The type that the given property is parsed into.
+     * 
+     * @param property
+     *     The property to read from guacamole.properties.
+     * 
+     * @return
+     *     A sorted collection of the the parsed values of the property as read
+     *     from guacamole.properties.
+     * 
+     * @throws GuacamoleException
+     *     If an error occurs while parsing the value for the given property in
+     *     guacamole.properties.
+     */
+    public default <Type> Collection<Type> getPropertyCollection(
+            GuacamoleProperty<Type> property) throws GuacamoleException {
+        
+        /* Pull the given property as a string. */
+        StringGuacamoleProperty stringProperty = new StringGuacamoleProperty() {
+            
+            @Override
+            public String getName() { return property.getName(); }
+            
+        };
+        
+        /* Parse the string to a Collection of the desired type. */
+        return property.parseValueCollection(getProperty(stringProperty));
+        
+    }
+    
+    /**
+     * Given a GuacamoleProperty, parses and returns the value set for that
+     * property in guacamole.properties, if any. If no value is found, a
+     * Collection is returned with the provided default value. The
+     * implementation of parsing and returning a collection of multiple
+     * values is up to the individual property implementations, and not all
+     * implementations will support reading and returning multiple values.
+     *
+     * @param <Type>
+     *     The type that the given property is parsed into.
+     * 
+     * @param property
+     *     The property to read from guacamole.properties.
+     * 
+     * @param defaultValue
+     *     The single value to return in the Collection if no value was given
+     *     in guacamole.properties.
+     * 
+     * @return
+     *     A sorted collection of the the parsed values of the property as read
+     *     from guacamole.properties, or a Collection with the single default
+     *     value provided.
+     * 
+     * @throws GuacamoleException
+     *     If an error occurs while parsing the value for the given property in
+     *     guacamole.properties.
+     */
+    public default <Type> Collection<Type> getPropertyCollection(
+            GuacamoleProperty<Type> property, Type defaultValue)
+            throws GuacamoleException {
+        
+        /* Pull the given property as a string. */
+        StringGuacamoleProperty stringProperty = new StringGuacamoleProperty() {
+            
+            @Override
+            public String getName() { return property.getName(); }
+            
+        };
+        
+        /* Check the value and return the default if null. */
+        String stringValue = getProperty(stringProperty);
+        if (stringValue == null)
+            return Collections.singletonList(defaultValue);
+        
+        /* Parse the string and return the collection. */
+        return property.parseValueCollection(stringValue);
+        
+    }
+    
+    /**
+     * Given a GuacamoleProperty, parses and returns the value set for that
+     * property in guacamole.properties, if any. If no value is found, the
+     * provided Collection of default values is returned. The
+     * implementation of parsing and returning a collection of multiple
+     * values is up to the individual property implementations, and not all
+     * implementations will support reading and returning multiple values.
+     *
+     * @param <Type>
+     *     The type that the given property is parsed into.
+     * 
+     * @param property
+     *     The property to read from guacamole.properties.
+     * 
+     * @param defaultValue
+     *     The Collection of values to return in the Collection if no value was
+     *     given in guacamole.properties.
+     * 
+     * @return
+     *     A sorted collection of the the parsed values of the property as read
+     *     from guacamole.properties, or a Collection with the single default
+     *     value provided.
+     * 
+     * @throws GuacamoleException
+     *     If an error occurs while parsing the value for the given property in
+     *     guacamole.properties.
+     */
+    public default <Type> Collection<Type> getPropertyCollection(
+            GuacamoleProperty<Type> property, Collection<Type> defaultValue)
+            throws GuacamoleException {
+        
+        /* Pull the given property as a string. */
+        StringGuacamoleProperty stringProperty = new StringGuacamoleProperty() {
+            
+            @Override
+            public String getName() { return property.getName(); }
+            
+        };
+        
+        /* Check the value and return the default if null. */
+        String stringValue = getProperty(stringProperty);
+        if (stringValue == null)
+            return defaultValue;
+        
+        /* Parse the string and return the collection. */
+        return property.parseValueCollection(stringValue);
+        
+    }
+    
     /**
      * Given a GuacamoleProperty, parses and returns the value set for that
      * property in guacamole.properties. An exception is thrown if the value
@@ -149,6 +297,43 @@ public interface Environment {
     public <Type> Type getRequiredProperty(GuacamoleProperty<Type> property)
             throws GuacamoleException;
     
+    /**
+     * Given a GuacamoleProperty, parses and returns a sorted Collection of
+     * values for that property in guacamole.properties. An exception is thrown
+     * if the value is not provided. The implementation of parsing and returning
+     * a collection of multiple values is up to the individual property
+     * implementations, and not all implementations will support reading and
+     * returning multiple values.
+     * 
+     * @param <Type>
+     *     The type that the given property is parsed into.
+     * 
+     * @param property
+     *     The property to read from guacamole.properties.
+     * 
+     * @return
+     *     A sorted Collection of the property as read from guacamole.properties.
+     * 
+     * @throws GuacamoleException 
+     *     If an error occurs while parsing the value for the given property in
+     *     guacamole.properties, or if the property is not specified.
+     */
+    public default <Type> Collection<Type> getRequiredPropertyCollection(
+            GuacamoleProperty<Type> property) throws GuacamoleException {
+        
+        /* Pull the given property as a string. */
+        StringGuacamoleProperty stringProperty = new StringGuacamoleProperty() {
+            
+            @Override
+            public String getName() { return property.getName(); }
+            
+        };
+        
+        /* Parse the string to a Collection of the desired type. */
+        return property.parseValueCollection(getRequiredProperty(stringProperty));
+        
+    }
+
     /**
      * Returns the connection information which should be used, by default, to
      * connect to guacd when establishing a remote desktop connection.

guacamole-ext/src/main/java/org/apache/guacamole/environment/LocalEnvironment.java

@@ -25,6 +25,8 @@ import java.io.FileInputStream;
 import java.io.FilenameFilter;
 import java.io.IOException;
 import java.io.InputStream;
+import java.util.Collection;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -354,6 +356,38 @@ public class LocalEnvironment implements Environment {
 
     }
     
+    @Override
+    public <Type> Collection<Type> getPropertyCollection(GuacamoleProperty<Type> property)
+            throws GuacamoleException {
+        
+        return property.parseValueCollection(getPropertyValue(property.getName()));
+        
+    }
+    
+    @Override
+    public <Type> Collection<Type> getPropertyCollection(GuacamoleProperty<Type> property,
+            Type defaultValue) throws GuacamoleException {
+        
+        Collection<Type> value = getPropertyCollection(property);
+        if (value == null)
+            return Collections.singletonList(defaultValue);
+        
+        return value;
+        
+    }
+    
+    @Override
+    public <Type> Collection<Type> getPropertyCollection(GuacamoleProperty<Type> property,
+            Collection<Type> defaultValue) throws GuacamoleException {
+        
+        Collection<Type> value = getPropertyCollection(property);
+        if (value == null)
+            return defaultValue;
+        
+        return value;
+        
+    }
+
     @Override
     public <Type> Type getRequiredProperty(GuacamoleProperty<Type> property)
             throws GuacamoleException {
@@ -366,6 +400,18 @@ public class LocalEnvironment implements Environment {
 
     }
     
+    @Override
+    public <Type> Collection<Type> getRequiredPropertyCollection(GuacamoleProperty<Type> property)
+            throws GuacamoleException {
+        
+        Collection<Type> value = getPropertyCollection(property);
+        if (value == null)
+            throw new GuacamoleServerException("Property " + property.getName() + " is required.");
+        
+        return value;
+        
+    }
+
     @Override
     public Map<String, ProtocolInfo> getProtocols() {
         return availableProtocols;

guacamole-ext/src/main/java/org/apache/guacamole/properties/FileGuacamoleProperty.java

@@ -20,6 +20,9 @@
 package org.apache.guacamole.properties;
 
 import java.io.File;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
 import org.apache.guacamole.GuacamoleException;
 
 /**
@@ -38,4 +41,26 @@ public abstract class FileGuacamoleProperty implements GuacamoleProperty<File> {
 
     }
     
+    @Override
+    public List<File> parseValueCollection(String value) throws GuacamoleException {
+        
+        // If no property is provided, return null.
+        if (value == null)
+            return null;
+        
+        // Split string into a list of individual values
+        List<String> stringValues = Arrays.asList(DELIMITER_PATTERN.split(value));
+        if (stringValues.isEmpty())
+            return null;
+        
+        // Translate values to Files and add to result array.
+        List<File> fileValues = new ArrayList<>();
+        for (String stringFile : stringValues) {
+            fileValues.add(new File(stringFile));
+        }
+
+        return fileValues;
+        
+    }
+
 }

guacamole-ext/src/main/java/org/apache/guacamole/properties/GuacamoleProperty.java

@@ -19,6 +19,9 @@
 
 package org.apache.guacamole.properties;
 
+import java.util.Collection;
+import java.util.Collections;
+import java.util.regex.Pattern;
 import org.apache.guacamole.GuacamoleException;
 
 /**
@@ -30,12 +33,21 @@ import org.apache.guacamole.GuacamoleException;
  */
 public interface GuacamoleProperty<Type> {
 
+    /**
+     * A pattern which matches against the delimiters between values. This is
+     * currently simply a semicolon and any following whitespace. Parts of the
+     * input string which match this pattern will not be included in the parsed
+     * result.
+     */
+    static final Pattern DELIMITER_PATTERN = Pattern.compile(";\\s*");
+    
     /**
      * Returns the name of the property in guacamole.properties that this
      * GuacamoleProperty will parse.
      *
-     * @return The name of the property in guacamole.properties that this
+     * @return
-     *         GuacamoleProperty will parse.
+     *     The name of the property in guacamole.properties that this
+     *     GuacamoleProperty will parse.
      */
     public String getName();
 
@@ -43,11 +55,37 @@ public interface GuacamoleProperty<Type> {
      * Parses the given string value into the type associated with this
      * GuacamoleProperty.
      *
-     * @param value The string value to parse.
+     * @param value
-     * @return The parsed value.
+     *     The string value to parse.
-     * @throws GuacamoleException If an error occurs while parsing the
+     * 
-     *                            provided value.
+     * @return
+     *     The parsed value.
+     * 
+     * @throws GuacamoleException
+     *     If an error occurs while parsing the provided value.
      */
     public Type parseValue(String value) throws GuacamoleException;
     
+    /**
+     * Parses the given string value into a Collection of values of the type
+     * associated with this GuacamoleProperty. The default implementation
+     * simply returns a list containing a single item as parsed by the
+     * parseValue method.
+     * 
+     * @param value
+     *     The string value to parse.
+     * 
+     * @return
+     *     A sorted Collection of the parsed values.
+     * 
+     * @throws GuacamoleException 
+     *     If an error occurs while parsing the provided value.
+     */
+    default public Collection<Type> parseValueCollection(String value)
+            throws GuacamoleException {
+        
+        return Collections.singletonList(parseValue(value));
+        
+    }
+
 }

guacamole-ext/src/main/java/org/apache/guacamole/properties/IntegerGuacamoleProperty.java

@@ -19,6 +19,9 @@
 
 package org.apache.guacamole.properties;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
 import org.apache.guacamole.GuacamoleException;
 import org.apache.guacamole.GuacamoleServerException;
 
@@ -43,4 +46,25 @@ public abstract class IntegerGuacamoleProperty implements GuacamoleProperty<Inte
 
     }
     
+    @Override
+    public List<Integer> parseValueCollection(String value) throws GuacamoleException {
+        
+        if (value == null)
+            return null;
+        
+        // Split string into a list of individual values
+        List<String> stringValues = Arrays.asList(DELIMITER_PATTERN.split(value));
+        if (stringValues.isEmpty())
+            return null;
+        
+        // Translate values to Integers, validating along the way.
+        List<Integer> intValues = new ArrayList<>();
+        for (String stringInt : stringValues) {
+            intValues.add(parseValue(stringInt));
+        }
+
+        return intValues;
+        
+    }
+
 }

guacamole-ext/src/main/java/org/apache/guacamole/properties/LongGuacamoleProperty.java

@@ -19,6 +19,9 @@
 
 package org.apache.guacamole.properties;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
 import org.apache.guacamole.GuacamoleException;
 import org.apache.guacamole.GuacamoleServerException;
 
@@ -43,4 +46,25 @@ public abstract class LongGuacamoleProperty implements GuacamoleProperty<Long> {
 
     }
     
+    @Override
+    public List<Long> parseValueCollection(String value) throws GuacamoleException {
+        
+        if (value == null)
+            return null;
+        
+        // Split string into a list of individual values
+        List<String> stringValues = Arrays.asList(DELIMITER_PATTERN.split(value));
+        if (stringValues.isEmpty())
+            return null;
+        
+        // Translate values to Longs, validating along the way.
+        List<Long> longValues = new ArrayList<>();
+        for (String stringLong : stringValues) {
+            longValues.add(parseValue(stringLong));
+        }
+
+        return longValues;
+        
+    }
+
 }

guacamole-ext/src/main/java/org/apache/guacamole/properties/StringGuacamoleProperty.java

@@ -19,6 +19,8 @@
 
 package org.apache.guacamole.properties;
 
+import java.util.Arrays;
+import java.util.List;
 import org.apache.guacamole.GuacamoleException;
 
 /**
@@ -31,4 +33,19 @@ public abstract class StringGuacamoleProperty implements GuacamoleProperty<Strin
         return value;
     }
     
+    @Override
+    public List<String> parseValueCollection(String value) throws GuacamoleException {
+        
+        if (value == null)
+            return null;
+        
+        // Split string into a list of individual values
+        List<String> stringValues = Arrays.asList(DELIMITER_PATTERN.split(value));
+        if (stringValues.isEmpty())
+            return null;
+        
+        return stringValues;
+        
+    }
+
 }

guacamole-ext/src/main/java/org/apache/guacamole/properties/StringListProperty.java

@@ -31,17 +31,14 @@ import org.apache.guacamole.GuacamoleException;
  * compatibility with the behavior of Java properties in general, only
  * whitespace at the beginning of each value is ignored; trailing whitespace
  * becomes part of the value.
+ * 
+ * @deprecated 
+ *     This class is now deprecated in favor of using the StringGuacamoleProperty
+ *     class with the parseValueCollection method.
  */
+@Deprecated
 public abstract class StringListProperty implements GuacamoleProperty<List<String>> {
 
-    /**
-     * A pattern which matches against the delimiters between values. This is
-     * currently simply a comma and any following whitespace. Parts of the
-     * input string which match this pattern will not be included in the parsed
-     * result.
-     */
-    private static final Pattern DELIMITER_PATTERN = Pattern.compile(",\\s*");
-
     @Override
     public List<String> parseValue(String values) throws GuacamoleException {
 

guacamole-ext/src/main/java/org/apache/guacamole/properties/TimeZoneGuacamoleProperty.java

@@ -19,6 +19,9 @@
 
 package org.apache.guacamole.properties;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
 import java.util.TimeZone;
 import java.util.regex.Pattern;
 import org.apache.guacamole.GuacamoleException;
@@ -57,4 +60,25 @@ public abstract class TimeZoneGuacamoleProperty
         
     }
     
+    @Override
+    public List<TimeZone> parseValueCollection(String value) throws GuacamoleException {
+        
+        if (value == null)
+            return null;
+        
+        // Split string into a list of individual values
+        List<String> stringValues = Arrays.asList(DELIMITER_PATTERN.split(value));
+        if (stringValues.isEmpty())
+            return null;
+        
+        // Translate values to Integers, validating along the way.
+        List<TimeZone> tzValues = new ArrayList<>();
+        for (String stringTz : stringValues) {
+            tzValues.add(parseValue(stringTz));
+        }
+
+        return tzValues;
+        
+    }
+    
 }

guacamole-ext/src/main/java/org/apache/guacamole/properties/URIGuacamoleProperty.java

@@ -21,6 +21,9 @@ package org.apache.guacamole.properties;
 
 import java.net.URI;
 import java.net.URISyntaxException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
 import org.apache.guacamole.GuacamoleException;
 import org.apache.guacamole.GuacamoleServerException;
 
@@ -46,4 +49,26 @@ public abstract class URIGuacamoleProperty implements GuacamoleProperty<URI> {
         
     }
     
+    @Override
+    public List<URI> parseValueCollection(String value) throws GuacamoleException {
+        
+        // Nothing provided, return nothing.
+        if (value == null)
+            return null;
+        
+        // Split string into a list of individual values
+        List<String> stringValues = Arrays.asList(DELIMITER_PATTERN.split(value));
+        if (stringValues.isEmpty())
+            return null;
+        
+        // Translate values to URIs, validating along the way.
+        List<URI> uriValues = new ArrayList<>();
+        for (String stringUri : stringValues) {
+            uriValues.add(parseValue(stringUri));
+        }
+
+        return uriValues;
+        
+    }
+    
 }