GUACAMOLE-462: Allow individual records to be identified and retrieved directly.

guacamole-ext/src/main/java/org/apache/guacamole/net/auth/ActivityRecord.java

@@ -78,6 +78,21 @@ public interface ActivityRecord extends ReadableAttributes {
      */
     public boolean isActive();
 
+    /**
+     * Returns the unique identifier assigned to this record, if any. If this
+     * record is not uniquely identifiable, this may be null. If provided, this
+     * unique identifier MUST be unique across all {@link ActivityRecord}
+     * objects within the same {@link ActivityRecordSet}.
+     *
+     * @return
+     *     The unique identifier assigned to this record, or null if this
+     *     record has no such identifier.
+     */
+    public default String getIdentifier() {
+        UUID uuid = getUUID();
+        return uuid != null ? uuid.toString() : null;
+    }
+
     /**
      * Returns a UUID that uniquely identifies this record. If provided, this
      * UUID MUST be deterministic and unique across all {@link ActivityRecord}

guacamole-ext/src/main/java/org/apache/guacamole/net/auth/ActivityRecordSet.java

@@ -57,6 +57,30 @@ public interface ActivityRecordSet<RecordType extends ActivityRecord> {
      */
     Collection<RecordType> asCollection() throws GuacamoleException;
 
+    /**
+     * Returns the record having the given unique identifier, if records within
+     * this set have unique identifiers. If records within this set do not have
+     * defined unique identifiers, this function has no effect.
+     *
+     * @param identifier
+     *     The unique identifier of the record to retrieve.
+     *
+     * @return
+     *     The record having the given unique identifier, or null if there is
+     *     no such record.
+     *
+     * @throws GuacamoleException
+     *     If an error occurs while retrieving the record.
+     */
+    default RecordType get(String identifier) throws GuacamoleException {
+        return asCollection().stream()
+                .filter((record) -> {
+                    String recordIdentifier = record.getIdentifier();
+                    return recordIdentifier != null && recordIdentifier.equals(identifier);
+                })
+                .findFirst().orElse(null);
+    }
+
     /**
      * Returns the subset of records which contain the given value. The
      * properties and semantics involved with determining whether a particular

guacamole-ext/src/main/java/org/apache/guacamole/net/auth/DecoratingActivityRecordSet.java

@@ -122,6 +122,17 @@ public abstract class DecoratingActivityRecordSet<RecordType extends ActivityRec
         };
     }
 
+    @Override
+    public RecordType get(String string) throws GuacamoleException {
+
+        RecordType record = super.get(string);
+        if (record != null)
+            return decorate(record);
+
+        return null;
+
+    }
+
     @Override
     public ActivityRecordSet<RecordType> sort(SortableProperty property,
             boolean desc) throws GuacamoleException {

guacamole-ext/src/main/java/org/apache/guacamole/net/auth/DelegatingActivityRecord.java

@@ -81,6 +81,11 @@ public class DelegatingActivityRecord implements ActivityRecord {
         return record.isActive();
     }
 
+    @Override
+    public String getIdentifier() {
+        return record.getIdentifier();
+    }
+
     @Override
     public UUID getUUID() {
         return record.getUUID();

guacamole-ext/src/main/java/org/apache/guacamole/net/auth/DelegatingActivityRecordSet.java

@@ -59,6 +59,11 @@ public class DelegatingActivityRecordSet<RecordType extends ActivityRecord>
         return recordSet;
     }
 
+    @Override
+    public RecordType get(String identifier) throws GuacamoleException {
+        return recordSet.get(identifier);
+    }
+
     @Override
     public Collection<RecordType> asCollection() throws GuacamoleException {
         return recordSet.asCollection();