| 1 | Use Case: Reading a Meter |
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| 2 | *********************************************************************** |
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| 3 | |
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| 4 | .. Description of a use case |
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| 5 | .. The description must be formulated as seen from system (not: actors) |
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| 6 | .. Describes those changes an (outside) actor can notice |
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| 7 | .. Short and abstract as possible, as long as necessary. |
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| 8 | .. Each use case must have at least one actor involved |
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| 9 | .. Each use case must have a trigger and a result |
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| 10 | |
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| 11 | |
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| 12 | Short Description |
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| 13 | ----------------------------------------------------------------------- |
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| 14 | |
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| 15 | A meter is read and the read values are stored in system. |
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| 16 | |
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| 17 | |
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| 18 | Actor(s) |
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| 19 | ----------------------------------------------------------------------- |
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| 20 | |
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| 21 | meter reader, web portal |
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| 22 | |
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| 23 | |
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| 24 | Trigger(s) |
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| 25 | ----------------------------------------------------------------------- |
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| 26 | |
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| 27 | a read-meter form is requested from portal |
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| 28 | |
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| 29 | |
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| 30 | Result(s) |
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| 31 | ----------------------------------------------------------------------- |
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| 32 | |
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| 33 | The new meter values are stored in database. |
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| 34 | |
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| 35 | |
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| 36 | Incoming Data |
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| 37 | ----------------------------------------------------------------------- |
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| 38 | |
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| 39 | username, password, meter id, amount, datetime of reading |
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| 40 | |
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| 41 | |
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| 42 | Outgoing Data |
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| 43 | ----------------------------------------------------------------------- |
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| 44 | |
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| 45 | login form, meter form, success message |
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| 46 | |
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| 47 | |
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| 48 | Precondition(s) |
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| 49 | ----------------------------------------------------------------------- |
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| 50 | |
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| 51 | The system is running |
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| 52 | |
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| 53 | |
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| 54 | Postcondition(s) |
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| 55 | ----------------------------------------------------------------------- |
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| 56 | |
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| 57 | The system is running |
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| 58 | |
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| 59 | |
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| 60 | Invariant(s) |
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| 61 | ----------------------------------------------------------------------- |
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| 62 | |
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| 63 | |
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| 64 | |
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| 65 | |
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| 66 | Essential Steps |
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| 67 | ----------------------------------------------------------------------- |
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| 68 | |
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| 69 | * authenticate meter reader |
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| 70 | * get meter id, meter value, datetime |
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| 71 | * check input values: |
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| 72 | |
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| 73 | * does the meter id exist? |
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| 74 | * if not, ask and add a new one |
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| 75 | * value >= old value? |
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| 76 | |
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| 77 | * add new reading in database |
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| 78 | * output success message |
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| 79 | |
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| 80 | |
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| 81 | Open Issues |
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| 82 | ----------------------------------------------------------------------- |
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| 83 | |
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| 84 | Meter data input can also be performed by some automatic system: |
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| 85 | |
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| 86 | - automatic meters send their data automatically (how does these |
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| 87 | data look like and where is it stored?) |
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| 88 | |
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| 89 | - a smartphone/tablet app might deliver the data by photograph/OCR |
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| 90 | |
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| 91 | These input devices need an API to deliver data or they require some |
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| 92 | API to be able to input data into the system. |
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| 93 | |
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| 94 | |
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| 95 | Remarks |
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| 96 | ----------------------------------------------------------------------- |
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| 97 | |
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| 98 | |
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| 99 | .. raw:: latex |
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| 100 | |
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| 101 | \pagebreak[2] |
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