package org.jgroups.protocols.rules;
import org.jgroups.View;
import org.jgroups.protocols.FD;
/**
* Rule which checks if the FD monitor is running when we have more than 1 member. If not, starts it.
* The rule uninstalls itself if no FD protocol is found.
* @author Bela Ban
* @since 3.3
*/
public class CheckFDMonitor extends Rule {
protected FD fd;
public String name() {
return getClass().getSimpleName();
}
public String description() {
return "Starts FD.Monitor if membership > 1 and monitor isn't running";
}
public void init() {
super.init();
fd=(FD)sv.getProtocolStack().findProtocol(FD.class);
if(fd == null) {
log.info("FD was not found, uninstalling myself (" + getClass().getSimpleName() + ")");
sv.uninstallRule(getClass().getSimpleName());
}
}
public boolean eval() {
return sv.getView() != null && sv.getView().size() > 1 && !fd.isMonitorRunning();
}
public String condition() {
View view=sv.getView();
return "Membership is " + (view != null? view.size() : "n/a") + ", FD.Monitor running=" + fd.isMonitorRunning();
}
public void trigger() throws Throwable {
System.out.println(sv.getLocalAddress() + ": starting failure detection");
fd.startFailureDetection();
}
public String toString() {
return CheckFDMonitor.class.getSimpleName() + ": " + condition();
}
}