| /* |
| * 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.beam.runners.core; |
| |
| import java.io.IOException; |
| import java.io.Serializable; |
| import org.apache.beam.sdk.coders.Coder; |
| import org.apache.beam.sdk.state.BagState; |
| import org.apache.beam.sdk.state.CombiningState; |
| import org.apache.beam.sdk.state.MapState; |
| import org.apache.beam.sdk.state.OrderedListState; |
| import org.apache.beam.sdk.state.SetState; |
| import org.apache.beam.sdk.state.State; |
| import org.apache.beam.sdk.state.StateSpec; |
| import org.apache.beam.sdk.state.ValueState; |
| import org.apache.beam.sdk.state.WatermarkHoldState; |
| import org.apache.beam.sdk.transforms.Combine.CombineFn; |
| import org.apache.beam.sdk.transforms.CombineWithContext.CombineFnWithContext; |
| import org.apache.beam.sdk.transforms.GroupByKey; |
| import org.apache.beam.sdk.transforms.windowing.TimestampCombiner; |
| |
| /** |
| * An address and specification for a persistent state cell. This includes a unique identifier for |
| * the location, the information necessary to encode the value, and details about the intended |
| * access pattern. |
| * |
| * <p>State can be thought of as a sparse table, with each {@code StateTag} defining a column that |
| * has cells of type {@code StateT}. |
| * |
| * <p>Currently, this can only be used in a step immediately following a {@link GroupByKey}. |
| * |
| * @param <StateT> The type of state being tagged. |
| */ |
| public interface StateTag<StateT extends State> extends Serializable { |
| |
| /** Append the UTF-8 encoding of this tag to the given {@link Appendable}. */ |
| void appendTo(Appendable sb) throws IOException; |
| |
| /** An identifier for the state cell that this tag references. */ |
| String getId(); |
| |
| /** The specification for the state stored in the referenced cell. */ |
| StateSpec<StateT> getSpec(); |
| |
| /** |
| * Bind this state tag. See {@link StateSpec#bind}. |
| * |
| * @deprecated Use the {@link StateSpec#bind} method via {@link #getSpec} for now. |
| */ |
| @Deprecated |
| StateT bind(StateBinder binder); |
| |
| /** |
| * Visitor for binding a {@link StateSpec} and to the associated {@link State}. |
| * |
| * @deprecated for migration only; runners should reference the top level {@link StateBinder} and |
| * move towards {@link StateSpec} rather than {@link StateTag}. |
| */ |
| @Deprecated |
| public interface StateBinder { |
| <T> ValueState<T> bindValue(StateTag<ValueState<T>> spec, Coder<T> coder); |
| |
| <T> BagState<T> bindBag(StateTag<BagState<T>> spec, Coder<T> elemCoder); |
| |
| <T> SetState<T> bindSet(StateTag<SetState<T>> spec, Coder<T> elemCoder); |
| |
| <KeyT, ValueT> MapState<KeyT, ValueT> bindMap( |
| StateTag<MapState<KeyT, ValueT>> spec, |
| Coder<KeyT> mapKeyCoder, |
| Coder<ValueT> mapValueCoder); |
| |
| <T> OrderedListState<T> bindOrderedList(StateTag<OrderedListState<T>> spec, Coder<T> elemCoder); |
| |
| <InputT, AccumT, OutputT> CombiningState<InputT, AccumT, OutputT> bindCombiningValue( |
| StateTag<CombiningState<InputT, AccumT, OutputT>> spec, |
| Coder<AccumT> accumCoder, |
| CombineFn<InputT, AccumT, OutputT> combineFn); |
| |
| <InputT, AccumT, OutputT> CombiningState<InputT, AccumT, OutputT> bindCombiningValueWithContext( |
| StateTag<CombiningState<InputT, AccumT, OutputT>> spec, |
| Coder<AccumT> accumCoder, |
| CombineFnWithContext<InputT, AccumT, OutputT> combineFn); |
| |
| /** |
| * Bind to a watermark {@link StateSpec}. |
| * |
| * <p>This accepts the {@link TimestampCombiner} that dictates how watermark hold timestamps |
| * added to the returned {@link WatermarkHoldState} are to be combined. |
| */ |
| WatermarkHoldState bindWatermark( |
| StateTag<WatermarkHoldState> spec, TimestampCombiner timestampCombiner); |
| } |
| } |