org.apache.kafka.streams.kstream.ValueTransformerSupplier Maven / Gradle / Ivy
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* 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.kafka.streams.kstream;
import org.apache.kafka.streams.processor.ConnectedStoreProvider;
/**
* A {@code ValueTransformerSupplier} interface which can create one or more {@link ValueTransformer} instances.
*
* The supplier should always generate a new instance each time {@link ValueTransformerSupplier#get()} gets called. Creating
* a single {@link ValueTransformer} object and returning the same object reference in {@link ValueTransformerSupplier#get()} would be
* a violation of the supplier pattern and leads to runtime exceptions.
*
* @param value type
* @param transformed value type
* @see ValueTransformer
* @see ValueTransformerWithKey
* @see ValueTransformerWithKeySupplier
* @see KStream#transformValues(ValueTransformerSupplier, String...)
* @see KStream#transformValues(ValueTransformerWithKeySupplier, String...)
* @see Transformer
* @see TransformerSupplier
* @see KStream#transform(TransformerSupplier, String...)
*/
public interface ValueTransformerSupplier extends ConnectedStoreProvider {
/**
* Return a newly constructed {@link ValueTransformer} instance.
* The supplier should always generate a new instance each time {@link ValueTransformerSupplier#get()} gets called.
*
* Creating a single {@link ValueTransformer} object and returning the same object reference in {@link ValueTransformerSupplier#get()}
* is a violation of the supplier pattern and leads to runtime exceptions.
*
* @return a newly constructed {@link ValueTransformer} instance
*/
ValueTransformer get();
}