public RetryInvocationHandler(
FailoverProxyProvider proxyProvider, Map<String, RetryPolicy> methodNameToPolicyMap) {
this.proxyProvider = proxyProvider;
this.defaultPolicy = RetryPolicies.TRY_ONCE_THEN_FAIL;
this.methodNameToPolicyMap = methodNameToPolicyMap;
this.currentProxy = proxyProvider.getProxy();
}
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
RetryPolicy policy = methodNameToPolicyMap.get(method.getName());
if (policy == null) {
policy = defaultPolicy;
}
// The number of times this method invocation has been failed over.
int invocationFailoverCount = 0;
int retries = 0;
while (true) {
// The number of times this invocation handler has ever been failed over,
// before this method invocation attempt. Used to prevent concurrent
// failed method invocations from triggering multiple failover attempts.
long invocationAttemptFailoverCount;
synchronized (proxyProvider) {
invocationAttemptFailoverCount = proxyProviderFailoverCount;
}
try {
Object ret = invokeMethod(method, args);
hasMadeASuccessfulCall = true;
return ret;
} catch (Exception e) {
boolean isMethodIdempotent =
proxyProvider
.getInterface()
.getMethod(method.getName(), method.getParameterTypes())
.isAnnotationPresent(Idempotent.class);
RetryAction action =
policy.shouldRetry(e, retries++, invocationFailoverCount, isMethodIdempotent);
if (action.action == RetryAction.RetryDecision.FAIL) {
if (action.reason != null) {
LOG.warn(
"Exception while invoking "
+ currentProxy.getClass()
+ "."
+ method.getName()
+ ". Not retrying because "
+ action.reason,
e);
}
throw e;
} else { // retry or failover
// avoid logging the failover if this is the first call on this
// proxy object, and we successfully achieve the failover without
// any flip-flopping
boolean worthLogging = !(invocationFailoverCount == 0 && !hasMadeASuccessfulCall);
worthLogging |= LOG.isDebugEnabled();
if (action.action == RetryAction.RetryDecision.FAILOVER_AND_RETRY && worthLogging) {
String msg =
"Exception while invoking "
+ method.getName()
+ " of class "
+ currentProxy.getClass().getSimpleName();
if (invocationFailoverCount > 0) {
msg += " after " + invocationFailoverCount + " fail over attempts";
}
msg += ". Trying to fail over " + formatSleepMessage(action.delayMillis);
if (LOG.isDebugEnabled()) {
LOG.debug(msg, e);
} else {
LOG.warn(msg);
}
} else {
if (LOG.isDebugEnabled()) {
LOG.debug(
"Exception while invoking "
+ method.getName()
+ " of class "
+ currentProxy.getClass().getSimpleName()
+ ". Retrying "
+ formatSleepMessage(action.delayMillis),
e);
}
}
if (action.delayMillis > 0) {
ThreadUtil.sleepAtLeastIgnoreInterrupts(action.delayMillis);
}
if (action.action == RetryAction.RetryDecision.FAILOVER_AND_RETRY) {
// Make sure that concurrent failed method invocations only cause a
// single actual fail over.
synchronized (proxyProvider) {
if (invocationAttemptFailoverCount == proxyProviderFailoverCount) {
proxyProvider.performFailover(currentProxy);
proxyProviderFailoverCount++;
currentProxy = proxyProvider.getProxy();
} else {
LOG.warn(
"A failover has occurred since the start of this method"
+ " invocation attempt.");
}
}
invocationFailoverCount++;
}
}
}
}
}
public RetryInvocationHandler(FailoverProxyProvider proxyProvider, RetryPolicy retryPolicy) {
this.proxyProvider = proxyProvider;
this.defaultPolicy = retryPolicy;
this.methodNameToPolicyMap = Collections.emptyMap();
this.currentProxy = proxyProvider.getProxy();
}
@Override
public void close() throws IOException {
proxyProvider.close();
}
