Download PDF (1.3 MB) - IBM Redbooks

Also, avoid constructing trace messages outside of conditional guard statement. For example,
the code in Example 3-1 creates a large string object even if tracing is disabled.
Example 3-1 Creating a large string object
String boTrace = bo.toString();
Although this pattern is always inefficient, it impacts performance even more if the BO size is
large. To avoid unnecessarily creating a BO when tracing is disabled, move the string
construction inside an if statement, as shown here:
if (tracing_on) System.out.println(bo.toString());
Avoiding buffer-doubling code
Study the memory implications of using Java data structures that expand their capacity based
on input (for example, StringBuffer and ByteArrayOutputStream). Such data structures
usually double their capacity when they run out of space. This doubling can produce
significant memory pressure when processing large objects. If possible, always assign an
initial size to such data structures.
3.2.12 Mediation Flow Component considerations
This section describes Mediation Flow Component (MFC) considerations for performance.
Using Extensible Stylesheet Language Transformation (XSLT) primitives
versus business object maps
The XSLT primitive offers two alternate transformation approaches in a mediation flow. If no
XSLT-specific function is required, then it is generally better to use the Business Object Map
primitive, which can be faster. The exception is when a Mediation Flow Component is trivial in
nature and the transformation is taking place at the /body level of the service message object
(SMO). In this case, XSLT is faster because the native XML bytes can be passed straight to
the XSLT engine. Native XML bytes are available if the XSLT transform primitive is the first in
the flow or only preceded by one or more of the following primitives:
► Route on Message Header (Message Filter primitive)
► XSLT primitive (Transforming on /body as the root)
► EndpointLookup without Xpath user properties.
► Event emitter (event header only)
In Business Process Manager 8.0, the Integration Designer enhances the XML Mapper to
use Business Object Maps for more cases, which results in better runtime performance. This
enhancement is described further in the presentation at the following location:
http://publib.boulder.ibm.com/infocenter/ieduasst/v1r1m0/topic/com.ibm.iea.iid/iid
/8.0/EnhancementsOverview/BPM80_IID_Enhancements.pdf
Chapter 3. Development best practices 43