org.apache.nifi.components.ConfigurableComponent 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.components;
import java.util.Collection;
import java.util.List;
import org.apache.nifi.annotation.lifecycle.OnConfigurationRestored;
public interface ConfigurableComponent {
/**
* Validates a set of properties, returning ValidationResults for any
* invalid properties. All defined properties will be validated. If they are
* not included in the purposed configuration, the default value will
* be used.
*
* @param context of validation
* @return Collection of validation result objects for any invalid findings
* only. If the collection is empty then the component is valid. Guaranteed
* non-null
*/
Collection validate(ValidationContext context);
/**
* @param name to lookup the descriptor
* @return the PropertyDescriptor with the given name, if it exists;
* otherwise, returns null
*/
PropertyDescriptor getPropertyDescriptor(String name);
/**
* Hook method allowing subclasses to eagerly react to a configuration
* change for the given property descriptor. This method will be invoked
* regardless of property validity. As an alternative to using this method,
* a component may simply get the latest value whenever it needs it and if
* necessary lazily evaluate it. Any throwable that escapes this method will
* simply be ignored.
*
* When NiFi is restarted, this method will be called for each 'dynamic' property that is
* added, as well as for each property that is not set to the default value. I.e., if the
* Properties are modified from the default values. If it is undesirable for your use case
* to react to properties being modified in this situation, you can add the {@link OnConfigurationRestored}
* annotation to a method - this will allow the Processor to know when configuration has
* been restored, so that it can determine whether or not to perform some action in the
* onPropertyModified method.
*
* @param descriptor the descriptor for the property being modified
* @param oldValue the value that was previously set, or null if no value
* was previously set for this property
* @param newValue the new property value or if null indicates the property
* was removed
*/
void onPropertyModified(PropertyDescriptor descriptor, String oldValue, String newValue);
/**
* Returns a {@link List} of all {@link PropertyDescriptor}s that this
* component supports.
*
* @return PropertyDescriptor objects this component currently supports
*/
List getPropertyDescriptors();
/**
* @return the unique identifier that the framework assigned to this
* component
*/
String getIdentifier();
}