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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespa.clustercontroller.core.restapiv2;
import com.yahoo.vespa.clustercontroller.core.RemoteClusterControllerTask;
import com.yahoo.vespa.clustercontroller.utils.staterestapi.errors.DeadlineExceededException;
import com.yahoo.vespa.clustercontroller.utils.staterestapi.errors.InternalFailure;
import com.yahoo.vespa.clustercontroller.utils.staterestapi.errors.StateRestApiException;
import com.yahoo.vespa.clustercontroller.utils.staterestapi.errors.UnknownMasterException;
public abstract class Request<Result> extends RemoteClusterControllerTask {
public enum MasterState {
MUST_BE_MASTER,
NEED_NOT_BE_MASTER
}
// TODO a lot of this logic could be replaced with a CompleteableFuture
private Exception failure = null;
protected boolean resultSet = false;
protected Result result = null;
private final MasterState masterState;
public Request(MasterState state) {
this.masterState = state;
}
public Result getResult() throws StateRestApiException, OtherMasterIndexException {
if (failure != null) {
if (failure instanceof OtherMasterIndexException) {
throw (OtherMasterIndexException) failure;
} else {
throw (StateRestApiException) failure;
}
}
if (!isCompleted()) {
throw new InternalFailure("Attempt to fetch result before it has been calculated");
}
if (!resultSet) {
throw new InternalFailure("Expected result to be set at this point.");
}
return result;
}
@Override
public final void doRemoteFleetControllerTask(Context context) {
try{
if (masterState == MasterState.MUST_BE_MASTER && !context.masterInfo.isMaster()) {
Integer masterIndex = context.masterInfo.getMaster();
if (masterIndex == null) throw new UnknownMasterException();
throw new OtherMasterIndexException(masterIndex);
}
result = calculateResult(context);
resultSet = true;
} catch (OtherMasterIndexException | StateRestApiException e) {
failure = e;
} catch (Exception e) {
failure = new InternalFailure("Caught unexpected exception");
failure.initCause(e);
}
}
private static String failureStringWithPossibleMessage(String prefix, String message) {
if (message != null && !message.isEmpty()) {
return String.format("%s: %s", prefix, message);
}
return prefix;
}
@Override
public void handleFailure(Failure failure) {
if (failure.getCondition() == FailureCondition.LEADERSHIP_LOST) {
this.failure = new UnknownMasterException(failureStringWithPossibleMessage(
"Leadership lost before request could complete", failure.getMessage()));
} else if (failure.getCondition() == FailureCondition.DEADLINE_EXCEEDED) {
this.failure = new DeadlineExceededException(failureStringWithPossibleMessage(
"Task exceeded its version wait deadline", failure.getMessage()));
}
}
@Override
public boolean isFailed() {
return (failure != null);
}
public abstract Result calculateResult(Context context) throws StateRestApiException, OtherMasterIndexException;
}
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