Storing and extracting data

Messaging and ESB

Implementing Messaging : Working with messages : Creating, populating, and accessing messages : Storing and extracting data

When writing data to a message, an application uses the name of the data type to specify the Java data type in the message; the ABL name is identical to the Java name. For example, Java uses the writeShort procedure to write a number to a StreamMessage as short. The ABL counterpart is the internal procedure writeShort(INTEGER).

In the context of extracting data from a message, there is an important difference between the ABL model and the Java model with respect to the names of the methods:

In Java, the name of the method determines the data type to which the extracted data is converted. For example, readLongString function extracts a value (for example, an INTEGER value from a StreamMessage) and converts it to a String value.

In ABL, the equivalent function is the readChar function to convert a value (such as an INTEGER value) to an ABL CHARACTER value.

The following table maps the ABL data types to the JMS data types for data storage.

Table 28. JMS and ABL data types for storing data
ABL data type	JMS data type
LOGICAL	boolean
INTEGER	byte
INTEGER	short
INTEGER	int
INT64	long
DECIMAL	long
DECIMAL	float
DECIMAL	double
CHARACTER	String
LONGCHAR	String
A single CHARACTER	char
RAW	byte array
MEMPTR	byte array (only with BytesMessage)
DATE	String
DATETIME	String
DATETIME-TZ	String

The following table maps the available conversions from JMS data types to ABL data types for data extraction.

Table 29. JMS and ABL data types for extracting data
JMS data type	ABL data type
boolean	LOGICAL or CHARACTER
byte	INTEGER, DECIMAL, or CHARACTER
short	INTEGER, DECIMAL, or CHARACTER
int	INTEGER, DECIMAL, or CHARACTER
long	INT64, DECIMAL or CHARACTER
float	DECIMAL or CHARACTER
double	DECIMAL or CHARACTER
String	CHARACTER or LONGCHAR
char	CHARACTER
byte array	RAW or MEMPTR (MEMPTR is available only with BytesMessage)
Java date string	DATE, DATETIME, or DATE-TZ