org.apache.flink.runtime.state.memory.MemFoldingState 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.flink.runtime.state.memory;

import org.apache.flink.api.common.functions.FoldFunction;
import org.apache.flink.api.common.state.FoldingState;
import org.apache.flink.api.common.state.FoldingStateDescriptor;
import org.apache.flink.api.common.typeutils.TypeSerializer;
import org.apache.flink.runtime.state.KvState;
import org.apache.flink.runtime.state.KvStateSnapshot;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

/**
 * Heap-backed partitioned {@link FoldingState} that is
 * snapshotted into a serialized memory copy.
 *
 * @param  The type of the key.
 * @param  The type of the namespace.
 * @param  The type of the values that can be folded into the state.
 * @param  The type of the value in the folding state.
 */
public class MemFoldingState
	extends AbstractMemState, FoldingStateDescriptor>
	implements FoldingState {

	private final FoldFunction foldFunction;

	public MemFoldingState(TypeSerializer keySerializer,
		TypeSerializer namespaceSerializer,
		FoldingStateDescriptor stateDesc) {
		super(keySerializer, namespaceSerializer, stateDesc.getSerializer(), stateDesc);
		this.foldFunction = stateDesc.getFoldFunction();
	}

	public MemFoldingState(TypeSerializer keySerializer,
		TypeSerializer namespaceSerializer,
		FoldingStateDescriptor stateDesc,
		HashMap> state) {
		super(keySerializer, namespaceSerializer, stateDesc.getSerializer(), stateDesc, state);
		this.foldFunction = stateDesc.getFoldFunction();
	}

	@Override
	public ACC get() {
		if (currentNSState == null) {
			currentNSState = state.get(currentNamespace);
		}
		return currentNSState != null ?
			currentNSState.get(currentKey) : null;
	}

	@Override
	public void add(T value) throws IOException {
		if (currentKey == null) {
			throw new RuntimeException("No key available.");
		}

		if (currentNSState == null) {
			currentNSState = new HashMap<>();
			state.put(currentNamespace, currentNSState);
		}

		ACC currentValue = currentNSState.get(currentKey);
		try {
			if (currentValue == null) {
				currentNSState.put(currentKey, foldFunction.fold(stateDesc.getDefaultValue(), value));
			} else {
					currentNSState.put(currentKey, foldFunction.fold(currentValue, value));

			}
		} catch (Exception e) {
			throw new RuntimeException("Could not add value to folding state.", e);
		}
	}

	@Override
	public KvStateSnapshot, FoldingStateDescriptor, MemoryStateBackend> createHeapSnapshot(byte[] bytes) {
		return new Snapshot<>(getKeySerializer(), getNamespaceSerializer(), stateSerializer, stateDesc, bytes);
	}

	public static class Snapshot extends AbstractMemStateSnapshot, FoldingStateDescriptor> {
		private static final long serialVersionUID = 1L;

		public Snapshot(TypeSerializer keySerializer,
			TypeSerializer namespaceSerializer,
			TypeSerializer stateSerializer,
			FoldingStateDescriptor stateDescs, byte[] data) {
			super(keySerializer, namespaceSerializer, stateSerializer, stateDescs, data);
		}

		@Override
		public KvState, FoldingStateDescriptor, MemoryStateBackend> createMemState(HashMap> stateMap) {
			return new MemFoldingState<>(keySerializer, namespaceSerializer, stateDesc, stateMap);
		}
	}
}