private void changeSubscription()

in java/ws-server/src/main/java/com/epam/deltix/tbwg/webapp/websockets/WSHandler.java [456:504]
43 lines of code
19 McCabe index (conditional complexity)

    private void changeSubscription(SubscribeMessage subscribeMessage, TickCursor cursor, PumpTask task) {
        synchronized (object) {
            task.buffer.clear();

            // working with symbols
            if (subscribeMessage.symbols != null) {
                if (subscribeMessage.symbols.subscribeToAll) {
                    cursor.subscribeToAllEntities();
                } else if (!subscribeMessage.symbols.isEmpty()) {
                    if (subscribeMessage.symbols.add != null && !subscribeMessage.symbols.add.isEmpty()) {
                        HashSet<IdentityKey> instruments = new HashSet<>();
                        for (DXTickStream stream : task.selection)
                            Collections.addAll(instruments, match(stream, subscribeMessage.symbols.add));
                        cursor.addEntities(collect(instruments), 0, instruments.size());
                    }
                    if (subscribeMessage.symbols.remove != null && !subscribeMessage.symbols.remove.isEmpty()) {
                        HashSet<IdentityKey> instruments = new HashSet<>();
                        for (DXTickStream stream : task.selection)
                            Collections.addAll(instruments, match(stream, subscribeMessage.symbols.remove));
                        cursor.removeEntities(collect(instruments), 0, instruments.size());
                    }
                }
            }

            // working with types
            if (subscribeMessage.types != null) {
                if (subscribeMessage.types.subscribeToAll) {
                    cursor.subscribeToAllTypes();
                } else if (!subscribeMessage.types.isEmpty()) {
                    if (subscribeMessage.types.add != null && !subscribeMessage.types.add.isEmpty()) {
                        cursor.addTypes(subscribeMessage.types.add.toArray(new String[]{}));
                    }
                    if (subscribeMessage.types.remove != null && !subscribeMessage.types.remove.isEmpty()) {
                        cursor.removeTypes(subscribeMessage.types.remove.toArray(new String[]{}));
                    }
                }
            }

            // working with from timestamp
            Instant instant = subscribeMessage.from;
            if (instant != null) {
                long timestamp = subscribeMessage.from.toEpochMilli();
                if (timestamp != Long.MIN_VALUE) {
                    cursor.reset(timestamp);
                }
            }
        }
        LOGGER.info().append("Changed subscription: ").append(subscribeMessage.toString()).commit();
    }