IAF samples

Your distribution contains two complete examples that demonstrate how the IAF can be used in practice – C and Java implementations of a text file adapter, including build scripts and complete source code.

The complete source code of the FileTransport transport layer plug-in and the StringCodec codec plug-in, in the FileTransport.c and StringCodec.c files.

The FileTransport transport layer plug-in can read and write messages from and to a text file. This makes it a useful tool in testing the IAF and the event correlator with files of sample messages.

The StringCodec codec plug-in can decode messages represented as strings containing a list of field names and values. The configuration properties for the plug-in allow customization of the syntactic characters used as field, name, and message separators (e.g. “,”, “=”, “;”).

A Makefile for compiling the plug-in sources with GNU Make on UNIX. This builds libFileTransport.so and libStringCodec.so, the plug-in binaries.

A ‘workspace’ file and dsp folder for compiling the plug-in sources with Microsoft’s Visual Studio .NET on Microsoft Windows. The make.bat batch file can be used to build the Windows plug-in binaries, FileTransport.dll and StringCodec.dll.

A sample configuration file, config.xml. This is an example of an IAF configuration that loads C plug-ins, configures them with plug-in properties, injects a specific EPL file into the event correlator, provides a simple event mapping, and configures the IAF for sending and receiving events to and from the event correlator.

A simple EPL file, simple.mon. This defines a monitor that examines the incoming events and selectively emits some back out to the IAF.

A text file, simple-feed.evt, with some test input messages that can be loaded by the File Transport plug-in, parsed by the String Codec plug-in, translated into Apama events by the Semantic Mapper, and then injected into the event correlator.

In order to run the example please follow the steps outlined in the README.txt file provided in the samples\iaf_plugin\c\simple folder.

On Windows you either need to copy the .dll into the bin folder, or else place it somewhere which is on your ‘path’, that is a location that is referenced by the PATH environment variable.

On UNIX you either need to copy the .so into the lib directory, or else place it somewhere which is on your ‘library path’, that is a directory that is referenced by the LD_LIBRARY_PATH environment variable.

The complete source code of the JFileTransport transport layer plug-in and the JStringCodec codec plug-in, in the src directory.

The JFileTransport transport layer plug-in can read and write messages from and to a text file. This makes it a useful tool in testing the IAF and the event correlator with files of sample messages.

In normal operation, JFileTransport sends String objects on to the codec for decoding; however by setting the upstreamNormalised plug-in property it is possible to use the transport plug-in in a different mode in which it also performs the functionality that the codec usually performs (in this case by calling the JStringCodec class directly). In this mode the transport passes IAF normalised event messages on to the codec plug-in, demonstrating the use of the pass-through JNullCodec plug-in provided with the Apama distribution.

The JStringCodec codec plug-in can convert between normalised events and messages represented as strings containing a list of field names and values. The configuration properties for the plug-in allow customization of the syntactic characters used as field, name, and message separators (e.g. “,”, “=”, “;”).

An Apache Ant build.xml file is included, for compiling the JFileAdapter.jar binary that contains both plug-ins (and works on all platforms).

A sample configuration file, config.xml. This is an example of an IAF configuration that loads Java transport and codec plug-ins, configures them with plug-in properties, provides an event mapping, and configures the IAF for sending and receiving events to and from the event correlator.

This configuration file also includes several optional configuration options for logging, custom JVM options, logging of unmapped events/messages, and use of non-standard correlator event batching.

A second configuration file, config-no-codec.xml that demonstrates how the standard JNullCodec plug-in can be used with a transport plug-in that incorporates codec functionality itself and produces normalised events directly.

A simple EPL file, simple.mon. This is identical to the file included with the C sample, and defines a monitor that examines the incoming events and selectively emits some back out to the IAF.

A text file, simple-feed.evt. This is identical to the file included with the C sample, and contains some test input messages that can be loaded by the File Transport plug-in, parsed by the String Codec plug-in, translated into Apama events by the Semantic Mapper, and then injected into the event correlator.

A reference file, simple-ref.evt, which shows the expected output file generated when the adapter is run. Note that this file is (only trivially) different to the reference file for the C plug-ins.

In order to run the example please follow the steps outlined in the README.txt file provided in the samples\iaf_plugin\java\simple folder.