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CHAPTER 17 ■ BLAZEDS
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and published in December 2007. AMF serializes data into a binary format, which is very useful for
sending large amounts of data and provides a much faster transmission.
BlazeDS vs. LCDS
Built on Java, the BlazeDS messaging service infrastructure contains pull patterns, pull patterns that look
and feel like push, and a couple of push or streaming patterns. It also has a proxy service that allows Flex
applications to access services outside their domains. Using AMF serialization with these patterns
provides speed and performance when sending or receiving messages. BlazeDS does not, however, have
the Real Time Messaging Protocol (RTMP) found in LCDS. This is an important drawback because the
HTTP and AMF streaming that BlazeDS provides is not reliable for many real-world applications. You
need RTMP, and more specifically RTMP tunneling, to make a dependable push pattern work. Hence,
the confusion about whether or not BlazeDS has push technology. It does, but LCDS is superior with
RTMP.
LCDS also scales better than BlazeDS. This capacity is what you pay for when you purchase LCDS.
Depending on the Java Virtual Machine’s (JVM) configuration and memory heap size, you can service a
few hundred clients with BlazeDS. With LCDS, however, you should be able to run that into the
thousands. But before you get discouraged by this, BlazeDS still has a lot of benefits, as you will soon see.
It provides some very useful tools, and, as opposed to LCDS, costs nothing to use.
What’s in a Name?
The names of these products and the fact that they offer similar features also causes confusion. Here’s a
short description of each that should help:
• LiveCycle ES (Enterprise Suite) integrates several products, and includes features
like PDF generation, digital signing, and data services. You can purchase the
various products separately or the entire suite.
• The data services component of LiveCycle ES is naturally called LiveCycle DS
(LCDS). This product used to be named Flex Data Services (FDS), which, of course,
causes still more confusion.
• BlazeDS has remoting, proxy, and messaging services. You will find these same
services in LCDS. However, BlazeDS left several items out, such as RTMP, message
queuing, lazy loading, and data synchronization.
• LiveCycle DS Community Edition is really BlazeDS with a paid Adobe support
subscription.
• Finally, LiveCycle Express is a single-CPU version of LCDS that can be installed
with ColdFusion 8.
Enterprise Service Bus (ESB)
Several people have noted with LCDS and BlazeDS that we are looking at an enterprise service bus
architecture. What is an ESB, what benefits does it bring, and why would we want to use one?
Typically, clients and services communicate directly with each other, as illustrated in Figure 17-1.
