FTP/FTPS Adapters custom trigger/poller - spring-integration

Question

First, I have just started looking at Spring Integration today, so I have very little experience. I already have a basic scheduled ftp file parser setup using spring integration:
<int:channel id="ftpIn" />
<int-ftp:inbound-channel-adapter
channel="ftpIn"
session-factory="ftpClientFactory"
filename-pattern="*.xml"
local-directory="${TEMP_DIR}">
<int:poller fixed-rate="${ftp.polling.rate}" />
</int-ftp:inbound-channel-adapter>
<bean id="ftpClientFactory" class="org.springframework.integration.ftp.session.DefaultFtpSessionFactory">
<property name="host" value="${ftp.host}" />
<property name="port" value="${ftp.port}" />
<property name="username" value="${ftp.username}" />
<property name="password" value="${ftp.password}" />
</bean>
<int:service-activator
input-channel="ftpIn"
method="handle"
ref="ftpInHandler" />
<bean id="ftpInHandler" class="thanks.for.looking.FtpInHandler" />
This works; however, I want to add additional functionality that checks (at a fixed-rate) if the system is ready before starting the scheduled (fixed-rate) ftp adapter. I am stuck on the best way to implement this. Any help or guidance is appreciated.
Best Regards,
Jared

Answer 1

<poller> has an option like <advice-chain>.
So you just need to write some custom Advice:
public class CheckSystemInterceptor implements MethodInterceptor {
Object invoke(MethodInvocation invocation) throws Throwable {
return mySystem.isOK() ? invocation.proceed() : null;
}
}
Configure it as a <bean> with your system checker and inject it into that <advice-chain>.
It will be invoked on each poll.