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NEW( ) Function |
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NEW(class$)
The NEW( ) function is used to create a reference to, or instance of, an object based on a specified class name (class$). If the class name already exists, then its definition is used. If the class has not been defined previously, the system attempts to load the program class$ .pvc and execute/define the DEF CLASS within it.
For example, Comp=NEW("Company") would create a new instance of a Company class. If the class definition for Company does not already exist in memory, then the system attempts to load the program Company.pvc. If this is successful, the NEW( ) function will return the object identifier assigned to the object.
If the label ON_CREATE exists in the class definition, it will be called to perform initialization logic. You can pass parameters to the NEW( ) function following the class name as well. These parameters will be passed to the ON_CREATE entry point.
Example:
C = NEW("Customer", File_number)
In Customer.pvx:
0010 ON_CREATE: ENTER File_no
See On Create/On Delete Logic.
Internally, each instance of an object sets a hidden reference count property, which is used for handling multiple accesses to the same object by different aspects of an application. Logically, when an object instance is first created, its reference count is set to 1 (one).
When an object is dropped, the system reduces the reference count by 1 (one). Once the count goes to 0 (zero), the object and all its contents are discarded. This reference count (number of instances) may be increased/decreased using the REF( ) function.
NEW( ) Function
REF( ) Function