Method Selection Logic

Control-O/COSMOS compares attributes of the object whose status is to be changed with rows in the Method database. Control-O/COSMOS attempts to match current status, desired status, object name, and object class with information specified for the various methods in the Method database.

• Each row in the Method database is assigned a score.
• Exact matches of object and method attributes are assigned the highest score.
• Partial matches (for example, matches with a generic status) are assigned an intermediate score.
• In certain columns, null can be specified. If an attribute of the object is compared with a method attribute specified as a null value, it is assigned a low score.
• Mismatches (for example, a comparison of status UP and status DOWN) result in rejection of the current method. Control-O/COSMOS continues with the next row in the Method database.

Below is a list of the columns in the Method database and how they are compared with attributes of the object under consideration. All columns listed below are analyzed. Control-O/COSMOS decides which method to invoke only after analyzing all rows in the Method database.

Each row in the Method database is assigned a score depending on how well it matches the description of the object to be modified. The Method rule specified in the row with the highest score is invoked. If no method matches the object under consideration, no action is performed.

The Method database columns are listed below in order of importance. For example, the first column (CURRENT) is assigned a more significant score than the second (DESIRED).

The following Method database columns are analyzed:

• CURRENT
  Compared with the current status of the object under consideration.
  • If the current status of the object matches the CURRENT column of the Method database row, the row is assigned a high score.
  • If the current status of the object matches a generic status specified in the CURRENT column in the Method database row, the row is assigned an intermediate score.
  • If the current status of the object does not match the CURRENT column, the row is rejected, and Control-O/COSMOS continues with the next row in the Method database.
• DESIRED
  Compared with the desired status of the object under consideration.
  • If the desired status of the object matches the DESIRED column of the Method database row, the row is assigned a high score.
  • If the desired status of the object matches a generic status specified in the DESIRED column in the Method database row, the row is assigned an intermediate score.
  • If a null value is specified in the Method database row, the row is assigned a low score.
  • If the desired status of the object does not match the DESIRED column, the row is rejected, and Control-O/COSMOS continues with the next row in the Method database.
• OBJDB
  Compared with the name of the Working Object database containing the object under consideration.
  • If the value in this column matches the name of the Working Object database, the row is assigned a high score.
  • If a null value is specified in this column, a low score is assigned.
  • If a value is specified in this column and it does not match the name of the object database, the row is rejected, and Control-O/COSMOS continues with the next row in the Method database.
• METCLASS
  Compared with the name and class of the object under consideration.
  • If the name of the object matches the value in this column, the row is assigned a high score.
  • If the name of the object does not match the METCLASS column but the name of the object class does match, the row is assigned an intermediate score.
  • If a null value is specified in this column, the row is assigned a low score.
  • If a value is specified in this column and it does not match the name of the object or the object class, the row is rejected, and Control-O/COSMOS continues with the next row in the Method database.

The scores assigned to matches in each column of a row are added together to determine its total score.

The rule named in the METHOD column of the row with the highest total score is invoked to process the object.

If more than one row is assigned the highest total score (that is, if there is a tie), the first- appearing row with the highest total score is chosen.

As already mentioned, if no row match was found (meaning, all rows were rejected), no action is performed on the object being considered.

Note: Rows rejected at any stage in the comparison are not considered candidates for processing the object.

The following table shows the possible combinations of matches of information that can invoke a Method rule. These combinations are listed in order of their scores (that is, row number 1 is the highest score, 2 the second highest, and so on).

Table 18 Method Rule Invocations