org.camunda.bpm.client.backoff.ErrorAwareBackoffStrategy Maven / Gradle / Ivy
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* Copyright Camunda Services GmbH and/or licensed to Camunda Services GmbH
* under one or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information regarding copyright
* ownership. Camunda licenses this file to you under the Apache License,
* Version 2.0; you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.camunda.bpm.client.backoff;
import org.camunda.bpm.client.exception.BadRequestException;
import org.camunda.bpm.client.exception.ConnectionLostException;
import org.camunda.bpm.client.exception.EngineException;
import org.camunda.bpm.client.exception.ExternalTaskClientException;
import org.camunda.bpm.client.exception.NotFoundException;
import org.camunda.bpm.client.exception.UnknownHttpErrorException;
import org.camunda.bpm.client.task.ExternalTask;
import java.util.List;
/**
* Provides a way to define a back off between fetch and lock requests.
*
*
Note: Since an implementation of this interface may be executed by multiple threads,
* it is recommended to implement the custom backoff strategy in a thread-safe manner.
*/
public interface ErrorAwareBackoffStrategy extends BackoffStrategy {
/**
* This is to provide compatibility with existing BackoffStrategy configurations.
* Do not override. Implementations of ErrorAwareBackoffStrategy should override
* {@link #reconfigure(List, ExternalTaskClientException)} instead.
*
* @param externalTasks which have been fetched
*/
@Override
default void reconfigure(List externalTasks) {
reconfigure(externalTasks, null);
}
/**
* Reconfigures the back off strategy based on the fetched external tasks and any error that
* might have occurred. It is invoked before {@link #calculateBackoffTime}.
*
*
The implementation might count the amount of invocations and realize a strategy reset.
*
* @param externalTasks which have been fetched
* @param exception can be of the following types:
* - {@link EngineException} if something went wrong during the engine execution (e.g., a persistence exception occurred).
*
- {@link BadRequestException} if an illegal operation was performed or the given data is invalid.
*
- {@link ConnectionLostException} if the connection could not be established.
*
- {@link UnknownHttpErrorException} if the HTTP status code is not known by the client.
*/
void reconfigure(List
externalTasks, ExternalTaskClientException exception);
/**
* Calculates the back off time and is invoked after {@link #reconfigure(List, ExternalTaskClientException)}.
*
* @return the back off time between fetch and lock requests in milliseconds
*/
long calculateBackoffTime();
}