# 1. Goal
A mobile crane hire company checks a lift plan before it dispatches a crane. The
dispatch office calls one check class for each lift plan. If the check fails, the
check class raises a class-based exception. The exception carries a message from a
new message class.

Create the message class, the exception class, and the check class.

# 2. Open questions
None.

# 3. Context
- All objects are in package $TMP.
- The dispatch office already exists. It calls the check class and shows the
  message text of the exception.
- No message class for lift plans exists yet.

# 4. Contract

## Message class {{P}}MSG_CRANE
Messages 001, 002, 003, 004 and 005 must exist. The Business rules give the
number, the type and the exact text of each message.

## Exception class {{P}}CX_CRANE_ERROR
- Public and final. It inherits from CX_STATIC_CHECK.
- Public constructor with these parameters:
  - iv_msgno, TYPE symsgno
  - iv_attr1, TYPE string, optional
  - iv_attr2, TYPE string, optional
- Public method get_message_text, returning VALUE rv_text TYPE string. The method
  returns the text of the message that the constructor received, with &1
  replaced by iv_attr1 and &2 replaced by iv_attr2.

## Check class {{P}}LIFT_CHECK
- Public and final.
- Public type ty_lift_plan with these components:
  - plan_id, TYPE string
  - crane_id, TYPE string
  - load_kg, TYPE decfloat34
  - capacity_kg, TYPE decfloat34
  - wind_kmh, TYPE decfloat34
- Public method check_lift_plan with the importing parameter iv_plan of type
  ty_lift_plan. The method raises {{P}}CX_CRANE_ERROR.

# 5. Business rules

## 5.1 Messages of {{P}}MSG_CRANE

| Number | Type | Text |
| ------ | ---- | ---- |
| 001 | E | Lift plan &1 has no crane |
| 002 | E | Lift plan &1 is too heavy for crane &2 |
| 003 | E | Lift plan &1 is blocked because of wind |
| 004 | W | Lift plan &1 is near the load limit |
| 005 | I | Lift plan &1 is approved |

Messages 001, 002 and 003 are errors. Message 004 is a warning. Message 005 is an
information message. The dispatch list shows messages 004 and 005.

## 5.2 Check of a lift plan
The method check_lift_plan checks the lift plan in this order:

1. If crane_id is initial, raise {{P}}CX_CRANE_ERROR with message 001 and
   attribute 1 = plan_id.
2. Else if load_kg is greater than capacity_kg, raise {{P}}CX_CRANE_ERROR with
   message 002, attribute 1 = plan_id, attribute 2 = crane_id.
3. Else if wind_kmh is greater than 60, raise {{P}}CX_CRANE_ERROR with message
   003 and attribute 1 = plan_id.
4. Else the method ends without an exception.

# 6. Constraints
- Release target: ABAP Platform 2025 (SAP_BASIS 816).
- Clean ABAP. Keep every method below 40 statements.
- Out of scope: no database table, no CDS view, no report. Do not change other
  objects in package $TMP.

# 7. Acceptance
- All objects are active and have no syntax error.
- The hidden tests pass.
- Write ABAP Unit tests: a global test class for the message class and the
  exception class, and local test classes for {{P}}LIFT_CHECK.