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COBOL Tutorial

COBOL XML GENERATE - Quick Reference

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Overview

XML GENERATE is a COBOL feature that allows you to automatically generate XML documents from COBOL data structures. It converts COBOL records and data items into well-formed XML format, making it easy to create XML output for web services, data exchange, or other XML-based applications.

Purpose and Usage

  • Automatic XML generation from COBOL data
  • Web service integration
  • Data exchange with modern systems
  • XML report generation
  • Legacy system modernization

Syntax

XML GENERATE follows specific syntax patterns for creating XML documents:

Basic XML GENERATE Syntax

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* Basic XML GENERATE syntax
XML GENERATE xml-output FROM data-structure.
 
* XML GENERATE with options
XML GENERATE xml-output FROM data-structure
    COUNT IN xml-length
    ON EXCEPTION
        PERFORM xml-error-handling
END-XML.
 
* XML GENERATE with specific options
XML GENERATE xml-output FROM customer-record
    COUNT IN xml-size
    ON EXCEPTION
        PERFORM handle-xml-error
    NOT ON EXCEPTION
        PERFORM process-generated-xml
END-XML.

XML GENERATE automatically creates XML from COBOL data structures.

Data Structure Definition

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* Data structure for XML generation
01  customer-record.
    05  customer-id PIC X(10).
    05  customer-name PIC X(50).
    05  customer-email PIC X(100).
    05  customer-address.
        10  street PIC X(100).
        10  city PIC X(50).
        10  state PIC X(2).
        10  zip-code PIC X(10).
    05  customer-phone PIC X(15).
 
01  xml-output PIC X(2000).
01  xml-length PIC 9(5).
 
* XML GENERATE usage
XML GENERATE xml-output FROM customer-record
    COUNT IN xml-length
    ON EXCEPTION
        DISPLAY "XML generation failed"
    NOT ON EXCEPTION
        DISPLAY "XML generated successfully"
        DISPLAY "Length: " xml-length
END-XML.

Practical Examples

Here are some practical uses of XML GENERATE in COBOL:

Customer Data Export

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* Exporting customer data to XML
DATA DIVISION.
WORKING-STORAGE SECTION.
01  customer-data.
    05  customer-id PIC X(10).
    05  customer-name PIC X(50).
    05  customer-email PIC X(100).
    05  customer-status PIC X(1).
01  xml-output PIC X(2000).
01  xml-length PIC 9(5).
 
PROCEDURE DIVISION.
EXPORT-CUSTOMER-XML.
    * Load customer data
    MOVE "CUST001" TO customer-id.
    MOVE "John Doe" TO customer-name.
    MOVE "john.doe@email.com" TO customer-email.
    MOVE "A" TO customer-status.
    
    * Generate XML
    XML GENERATE xml-output FROM customer-data
        COUNT IN xml-length
        ON EXCEPTION
            DISPLAY "Error generating XML"
            PERFORM error-handling
        NOT ON EXCEPTION
            DISPLAY "XML generated successfully"
            PERFORM save-xml-to-file
    END-XML.
    
    STOP RUN.
 
SAVE-XML-TO-FILE.
    * Save generated XML to file
    OPEN OUTPUT xml-file.
    WRITE xml-record FROM xml-output.
    CLOSE xml-file.
    DISPLAY "XML saved to file".
 
* Generated XML example:
* 
*   CUST001
*   John Doe
*   john.doe@email.com
*   A
*

Exporting customer data to XML format using XML GENERATE.

Web Service Response

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* Creating web service response XML
DATA DIVISION.
WORKING-STORAGE SECTION.
01  service-response.
    05  response-status PIC X(10).
    05  response-message PIC X(100).
    05  response-data.
        10  data-count PIC 9(4).
        10  data-items OCCURS 10 TIMES.
            15  item-id PIC X(10).
            15  item-name PIC X(50).
            15  item-value PIC 9(8)V99.
01  xml-response PIC X(5000).
01  response-length PIC 9(5).
 
PROCEDURE DIVISION.
CREATE-WEB-SERVICE-RESPONSE.
    * Prepare response data
    MOVE "SUCCESS" TO response-status.
    MOVE "Data retrieved successfully" TO response-message.
    MOVE 3 TO data-count.
    
    * Set data items
    MOVE "ITEM001" TO item-id(1).
    MOVE "Product A" TO item-name(1).
    MOVE 100.50 TO item-value(1).
    
    MOVE "ITEM002" TO item-id(2).
    MOVE "Product B" TO item-name(2).
    MOVE 200.75 TO item-value(2).
    
    MOVE "ITEM003" TO item-id(3).
    MOVE "Product C" TO item-name(3).
    MOVE 150.25 TO item-value(3).
    
    * Generate XML response
    XML GENERATE xml-response FROM service-response
        COUNT IN response-length
        ON EXCEPTION
            PERFORM handle-generation-error
        NOT ON EXCEPTION
            PERFORM send-xml-response
    END-XML.
    
    STOP RUN.
 
SEND-XML-RESPONSE.
    * Send XML response to client
    DISPLAY "Content-Type: application/xml".
    DISPLAY "Content-Length: " response-length.
    DISPLAY xml-response.
 
* Generated XML example:
* 
*   SUCCESS
*   Data retrieved successfully
*   
*     3
*     
*       ITEM001
*       Product A
*       100.50
*     
*     
*   
*

Creating web service response XML using XML GENERATE.

Best Practices

  • Always provide exception handling for XML generation errors.
  • Use meaningful data structure names that will become XML element names.
  • Validate data before generating XML to ensure proper output.
  • Consider the size of the output field to accommodate the generated XML.
  • Test XML generation with various data scenarios.
  • Document the expected XML structure and format.

Common Pitfalls

  • Not providing adequate space for generated XML output.
  • Failing to handle XML generation exceptions.
  • Using inappropriate data types that don\'t convert well to XML.
  • Not considering XML namespace requirements.
  • Creating overly complex data structures that generate confusing XML.

Test Your Knowledge

1. What is XML GENERATE in COBOL?

  • A file operation
  • An XML generation mechanism
  • A data declaration
  • A program structure

2. What does XML GENERATE do?

  • Parses XML data
  • Generates XML from COBOL data
  • Validates XML
  • Transforms XML

3. What type of data can XML GENERATE process?

  • Only numeric data
  • Only alphanumeric data
  • COBOL data structures and records
  • Only file data

4. Where is the generated XML stored?

  • In a file
  • In a COBOL field
  • In memory
  • All of the above

5. What is the primary benefit of using XML GENERATE?

  • Faster processing
  • Automatic XML creation from COBOL data
  • Better error handling
  • Memory efficiency

Frequently Asked Questions

Related Concepts

XML PARSE

Parsing XML data in COBOL.

Web Services

Creating web services with XML.

Data Exchange

Exchanging data with external systems.

Legacy Modernization

Modernizing legacy COBOL applications.

XML Processing

Comprehensive XML processing in COBOL.

XML PARSEALPHANUMERIC-FUNCTION