org.apache.nifi.annotation.behavior.RequiresInstanceClassLoading 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.annotation.behavior;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Inherited;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* Marker annotation a component can use to indicate that the framework should create a new ClassLoader
* for each instance of the component, copying all resources from the component's NARClassLoader to a
* new ClassLoader which will only be used by a given instance of the component.
*
* If cloneAncestorResources is set to true, the instance ClassLoader will include ancestor resources up to the
* first ClassLoader containing a controller service API referenced by the component, or up to the Jetty NAR.
*
* Example #1 - PutHDFS has this flag set to true and does not reference any controller services, so it will include
* resources from nifi-hadoop-nar, nifi-hadoop-libraries-nar, and nifi-standard-services-api-nar, stopping at nifi-jetty-nar.
*
* Example #2 - If PutHDFS referenced an SSLContext and has this flag set to true, then it would include
* resources from nifi-hadoop-nar, nifi-hadoop-libraries-nar, and stop before nifi-standard-services-api-nar.
*
* Example #3 - HBaseClientService_1_1_2 does not have this flag set so it defaults to false, and therefore includes
* only resources from the nifi-hbase-client-service-1_1_2-nar.
*
* NOTE: When this annotation is used it is important to note that each added instance of the component will increase
* the overall memory footprint more than that of a component without this annotation.
*/
@Documented
@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Inherited
public @interface RequiresInstanceClassLoading {
boolean cloneAncestorResources() default false;
}