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COBOL Tutorial

COBOL RAISED - Quick Reference

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Overview

The RAISED clause in COBOL is used to check whether an exception has been raised during program execution. It returns a boolean condition that can be used in conditional statements to determine if a specific exception occurred, enabling conditional error handling and program flow control.

Purpose and Usage

  • Exception detection and checking
  • Conditional error handling
  • Program flow control based on exceptions
  • Error recovery decision making
  • Exception status monitoring

Syntax

The RAISED clause follows specific syntax patterns:

Basic Syntax

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* Basic RAISED clause usage
IF exception-name RAISED
    PERFORM exception-handling
END-IF.
 
* RAISED in conditional statements
IF validation-error RAISED
    DISPLAY "Validation error occurred"
    PERFORM validation-error-handling
END-IF.
 
* Multiple exception checking
IF file-error RAISED OR data-error RAISED
    PERFORM general-error-handling
END-IF.
 
* RAISED with NOT
IF NOT business-rule-error RAISED
    PERFORM normal-processing
END-IF.

RAISED is used in conditional statements to check for exceptions.

Exception Checking Patterns

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* Checking for specific exceptions
IF invalid-input RAISED
    DISPLAY "Invalid input detected"
    PERFORM input-error-handling
END-IF.
 
* Checking multiple exceptions
IF file-not-found RAISED OR access-denied RAISED
    DISPLAY "File access problem"
    PERFORM file-error-handling
END-IF.
 
* Checking for no exceptions
IF NOT any-exception RAISED
    DISPLAY "Operation completed successfully"
    PERFORM success-processing
END-IF.
 
* Complex exception checking
EVALUATE TRUE
    WHEN validation-error RAISED
        PERFORM validation-handling
    WHEN system-error RAISED
        PERFORM system-error-handling
    WHEN business-error RAISED
        PERFORM business-error-handling
    WHEN OTHER
        PERFORM general-error-handling
END-EVALUATE.

Practical Examples

Here are some practical uses of the RAISED clause in COBOL:

Data Processing with Exception Checking

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* Data processing with RAISED checking
PROCEDURE DIVISION.
PROCESS-DATA-RECORDS.
    * Process each record
    PERFORM UNTIL end-of-file
        READ data-file
            AT END
                MOVE "Y" TO end-of-file-flag
            NOT AT END
                PERFORM process-record
        END-READ
        
        * Check for processing exceptions
        IF data-validation-error RAISED
            DISPLAY "Data validation failed for record"
            PERFORM validation-error-handling
        END-IF
        
        IF business-rule-violation RAISED
            DISPLAY "Business rule violated for record"
            PERFORM business-error-handling
        END-IF
        
        IF NOT any-error RAISED
            ADD 1 TO records-processed
            DISPLAY "Record processed successfully"
        END-IF
    END-PERFORM.
    
    * Final status check
    IF processing-error RAISED
        DISPLAY "Processing completed with errors"
    ELSE
        DISPLAY "All records processed successfully"
    END-IF.

Using RAISED to check for exceptions during data processing.

File Operations with Exception Handling

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* File operations with RAISED checking
PROCEDURE DIVISION.
FILE-OPERATIONS.
    * Open file with exception checking
    OPEN INPUT data-file.
    IF file-not-found RAISED
        DISPLAY "Data file not found"
        PERFORM file-not-found-handling
        STOP RUN
    END-IF.
    
    IF access-denied RAISED
        DISPLAY "Access denied to data file"
        PERFORM access-denied-handling
        STOP RUN
    END-IF.
    
    * Read file records
    PERFORM UNTIL end-of-file
        READ data-file
            AT END
                MOVE "Y" TO end-of-file-flag
            NOT AT END
                PERFORM process-record
        END-READ
        
        * Check for read exceptions
        IF read-error RAISED
            DISPLAY "Error reading record"
            PERFORM read-error-handling
        END-IF
        
        IF data-corruption RAISED
            DISPLAY "Data corruption detected"
            PERFORM data-corruption-handling
        END-IF
    END-PERFORM.
    
    * Close file
    CLOSE data-file.
    IF close-error RAISED
        DISPLAY "Error closing file"
        PERFORM close-error-handling
    END-IF.

Using RAISED to check for file operation exceptions.

Best Practices

  • Check for exceptions immediately after operations that might raise them.
  • Use specific exception names rather than generic checks when possible.
  • Provide appropriate error handling for each type of exception.
  • Consider the order of exception checking for proper error handling.
  • Use RAISED in combination with other error handling mechanisms.
  • Document the exceptions that each operation might raise.

Common Pitfalls

  • Not checking for exceptions after operations that might raise them.
  • Using generic exception checking instead of specific exception names.
  • Not providing appropriate error handling for checked exceptions.
  • Checking for exceptions in the wrong order.
  • Assuming that no exception means success without proper validation.

Test Your Knowledge

1. What is the primary purpose of the RAISED clause in COBOL?

  • To raise exceptions
  • To check if an exception has been raised
  • To terminate the program
  • To display error messages

2. When is the RAISED clause typically used?

  • Before executing statements
  • After executing statements to check for exceptions
  • During compilation
  • Only in debugging

3. What does RAISED return?

  • A numeric value
  • A boolean condition (true/false)
  • An error message
  • A program status

4. How do you use RAISED in conditional statements?

  • IF RAISED exception-name
  • IF exception-name RAISED
  • CHECK RAISED exception-name
  • TEST RAISED exception-name

5. What is the relationship between RAISE and RAISED?

  • They are the same
  • RAISE creates exceptions, RAISED checks for them
  • RAISED is obsolete
  • They cannot be used together

Frequently Asked Questions

Related Concepts

RAISE Statement

Raising exceptions in COBOL.

Exception Handling

Comprehensive exception handling in COBOL.

ON EXCEPTION

Handling exceptions in COBOL.

Error Handling

Error handling strategies and best practices.

Conditional Logic

Using conditional statements in COBOL.

RAISESAME RECORD AREA