Github user jmuehlner commented on a diff in the pull request:
https://github.com/apache/incubator-guacamole-client/pull/191#discussion_r140896419
--- Diff:
guacamole-ext/src/main/java/org/apache/guacamole/net/auth/ActivityRecordSet.java
---
@@ -0,0 +1,128 @@
+/*
+ * 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.net.auth;
+
+import java.util.Collection;
+import org.apache.guacamole.GuacamoleException;
+
+/**
+ * A set of all available records related to a type of activity which has a
+ * defined start and end time, such as a user being logged in or
connected, or a
+ * subset of those records.
+ *
+ * @param <RecordType>
+ * The type of ActivityRecord contained within this set.
+ */
+public interface ActivityRecordSet<RecordType extends ActivityRecord> {
+
+ /**
+ * All properties of activity records which can be used as sorting
+ * criteria.
+ */
+ enum SortableProperty {
+
+ /**
+ * The date and time when the activity associated with the record
+ * began.
+ */
+ START_DATE
+
+ };
+
+ /**
+ * Returns all records within this set as a standard Collection.
+ *
+ * @return
+ * A collection containing all records within this set.
+ *
+ * @throws GuacamoleException
+ * If an error occurs while retrieving the records within this
set.
+ */
+ Collection<RecordType> asCollection() throws GuacamoleException;
+
+ /**
+ * Returns the subset of records which contain the given value. The
+ * properties and semantics involved with determining whether a
particular
+ * record "contains" the given value is implementation dependent. This
--- End diff --
It doesn't look like any implementations actually mutate the
`ActivityRecordSet` when `contains()` is called. Do you expect that this will
be the case? If so, why?
---
