@Override
    public SharedConnectionDefinition get(String key) {
        
        // There are no null share keys
        if (key == null)
            return null;

        // Update the last access time and return the SharedConnectionDefinition
        return connectionMap.get(key);

    }
Keeps track of the share key to SharedConnectionDefinition mapping.
extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-base/src/main/java/org/apache/guacamole/auth/jdbc/sharing/HashSharedConnectionMap.java