samza-api/src/main/java/org/apache/samza/system/descriptors/TransformingInputDescriptorProvider.java

/*
 * 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.samza.system.descriptors;

import org.apache.samza.serializers.Serde;

/**
 * Interface for advanced {@link SystemDescriptor}s that constrain the type of returned {@link InputDescriptor}s to
 * their own {@link InputTransformer} function result types.
 *
 * @param <InputTransformerType> type of the system level {@link InputTransformer} results
 */
public interface TransformingInputDescriptorProvider<InputTransformerType> {

  /**
   * Gets a {@link InputDescriptor} for an input stream on this system. The stream has the provided
   * stream level serde, and the default system level {@link InputTransformer}.
   * <p>
   * The type of messages in the stream is the type of messages returned by the default system level
   * {@link InputTransformer}
   *
   * @param streamId id of the input stream
   * @param serde stream level serde for the input stream
   * @return an {@link InputDescriptor} for the input stream
   */
  InputDescriptor<InputTransformerType, ? extends InputDescriptor> getInputDescriptor(String streamId, Serde serde);
}