A simple plug-in in Java
The simple plug-in sample in the samples\correlator_plugin\java directory of your Apama installation is comparable to the similar C and C++ simple plug-in samples.
The Java code for the SimplePlugin class contains the public static test method. (Methods that will be called from EPL code need to be public and static.)
public class SimplePlugin
{
public static final String TEST_STRING = "Hello, World";
public static String test(String arg)
{
System.out.println("SimplePlugin function test called");
System.out.println("arg = "+arg);
System.out.println("return value = "+TEST_STRING);
return TEST_STRING;
}
}
The SimplePlugin.xml file is the deployment descriptor and contains the following <plugin> stanza that illustrates how to specify the plug-in.
The SimplePlugin.mon file contains the EPL code. It imports the plug-in and calls the test method.
monitor SimplePluginTest {
// Load the plugin
import "SimplePlugin" as simple;
// To hold the return value
string ret;
string arg;
action onload {
// Call plugin function
arg := "Hello, Simple Plugin";
ret := simple.test(arg);
// Print out return value
log "simple.test = " + ret at INFO;
log "arg = " + arg at INFO;
}
}