org.apache.nifi.reporting.ReportingTask Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); 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.apache.nifi.reporting;
import org.apache.nifi.annotation.behavior.Stateful;
import org.apache.nifi.annotation.lifecycle.OnConfigurationRestored;
import org.apache.nifi.components.ConfigurableComponent;
/**
* Defines a task that is responsible for reporting status information to
* external destinations. All implementations of this class must have a default
* constructor.
*
*
* ReportingTasks are discovered using Java's
* ServiceLoader mechanism. As a result, all implementations must
* follow these rules:
*
*
* - The implementation must implement this interface.
* - The implementation must have a file named
* org.apache.nifi.reporting.ReportingTask located within the jar's
*
META-INF/services directory. This file contains a list of
* fully-qualified class names of all ReportingTasks in the jar,
* one-per-line.
* - The implementation must support a default constructor.
*
*
*
*
* ReportingTasks are scheduled on a delayed interval with a single thread.
* Therefore, implementations are not required to be thread-safe.
*
*
*
* ReportingTasks may choose to annotate a method with the
* {@link OnConfigurationRestored @OnConfigurationRestored} annotation. If this is done, that method
* will be invoked after all properties have been set for the ReportingTask and
* before it is scheduled to run. If the method throws an Exception, the
* ReportingTask will be Administratively yielded and will not run for the
* configured period of time.
*
*/
public interface ReportingTask extends ConfigurableComponent {
/**
* Provides the Reporting Task with access to objects that may be of use
* throughout the life of the service
*
* @param config of initialization context
* @throws org.apache.nifi.reporting.InitializationException if unable to init
*/
void initialize(ReportingInitializationContext config) throws InitializationException;
/**
* This method is called on a scheduled interval to allow the Reporting Task
* to perform its tasks.
*
* @param context reporting context
*/
void onTrigger(ReportingContext context);
/**
* Indicates whether this reporting task, configured with the given {@link ReportingContext}, stores state.
* @param context provides access to convenience methods for obtaining property values
* @return True if this reporting task stores state
*/
default boolean isStateful(ReportingContext context) {
return this.getClass().isAnnotationPresent(Stateful.class);
}
}