Converting between Common Base Event primitive types and XML data types

When event attributes are used in expressions that accept input from inbound events or in expressions that populate outbound events, they are converted to XML schema data types. This conversion applies only to events based on Common Base Event definitions. XSD-based event part definitions have attributes and elements that are already defined using XSD types, so no conversion is necessary.

Event attributes that are used in events based on Common Base Event definitions must have one of the following nine primitive types: byte, short, int, long, float, double, string, dateTime, and boolean. These types are converted to XML schema data types when:

Event attributes are read by maps taking input from inbound events
Event attributes are written by maps populating outbound events

The following conversions are applied:

byte <-> xs:integer
short <-> xs:integer
int <-> xs:integer
long <-> xs:integer
float <-> xs:decimal
double <-> xs:decimal
string <-> xs:string
dateTime <-> xs:dateTime
boolean <-> xs:boolean

Integers that are larger than the largest value that can be held in an event attribute of type byte, short, int, or long are right-truncated to the number of bits in the result (that is, if the value is too large to fit in the event attribute, the bits that do not fit are thrown away). For example, if you map the integer 1000 to a (signed) byte attribute, only 8 bits are kept, which results in the number -24. Similarly, the integer 1024 is mapped to 0. If a value assigned to a metric is outside the range that is allowed for its type, the value will not be displayed correctly in the dashboards.

The following range of numbers can be held in an event attribute depending on its type:

Table 1.
Type	Range of Numbers
byte	from -128 to 127, inclusive
short	from -32768 to 32767, inclusive
int	from -2147483648 to 2147483647, inclusive
long	from -9223372036854775808 to 9223372036854775807, inclusive

If a value assigned to a metric is outside the range that is allowed for its type, the value will not be displayed correctly in the dashboards.

The XML schema data type duration has two totally ordered subtypes: yearMonthDuration and dayTimeDuration (see http://www.w3.org/TR/xquery-operators/#duration-subtypes). Only dayTimeDuration values are currently supported for any attributes or expressions with a type of duration.

Many decimal numbers (for example 1.20, which is represented in binary as 1.001100110011 ... ) cannot be represented as a binary floating point number with a finite number of bits. Therefore, rounding errors are inevitable when decimal data is transferred using event attributes of type float or double. To avoid rounding errors, either convert decimal numbers to strings, or convert decimal numbers to large enough integers (such as longs) by multiplying by a power of 10 (10, 100, 1000, or whatever size you need to change the decimal into a whole number).