Xiaofei's Computer Knowledge Miscellaneous Shop

Java collections are categorized into several main interfaces:

• List: Ordered collections that allow duplicates.
  • ArrayList: Dynamic array; fast lookups, slow insertions/deletions.
  • LinkedList: Doubly-linked list; slow lookups, fast insertions/deletions.
  • Vector: Thread-safe dynamic array (similar to ArrayList).
• Set: Collections that contain no duplicate elements.
  • HashSet: Hash table based; unordered.
  • LinkedHashSet: Hash table + linked list; maintains insertion order.
  • TreeSet: Red-Black tree based; sorted.
• Queue: Designed for holding elements prior to processing.
  • LinkedList: Implements Queue for FIFO (First-In-First-Out) operations.
  • PriorityQueue: Priority heap; sorted by natural order or a custom comparator.
• Map: Key-value pairs.
  • HashMap: Hash table; unordered; keys must be unique.
  • LinkedHashMap: Hash table + linked list; maintains insertion order.
  • TreeMap: Red-Black tree; sorted by keys; keys cannot be null.
  • ConcurrentHashMap: Thread-safe hash table; neither keys nor values can be null.

The production process for finished cigarettes involves several integrated systems (MES, WMS, and Control Systems) with the following workflow:

1. Production Planning: Users create production plans and import them into the MES system, specifying the quantity of cigarette boxes to be produced per machine.
2. Brand Management: Brand basic information is issued by the China Tobacco master data system. Users maintain process information (quality parameters for silk making and wrapping, and process information) in the MES, which is then sent to the underlying control system for data collection.
3. Instruction Execution: Production instruction orders (including brand info) are sent to the control system via intermediate tables. The control system returns work order details (shift, start/end time, brand, batch, order number) and updates production status (PLC dispatch, started, completed) via APIs.
4. Yield Tracking: Yield is tracked via yield confirmation forms linked to work orders. Data is sourced from both the underlying system (automated collection) and manual user entry, requiring an approval process upon completion.
5. Material Management:
   • Materials are linked to work orders via warehouse entry/exit records.
   • Inbound orders are provided by WMS interfaces; each item in a multi-material document generates a separate record.
   • Material inspection is performed by laboratories, with data transmitted to MES inspection work order details via TCP, UDP, OPC, or serial ports.
6. Consumption Tracking: WMS provides total material usage per machine. Manual entries are used to record material transfers between machines, and the MES automatically aggregates and calculates totals at the end of each shift.