afedulov commented on code in PR #23777: URL: https://github.com/apache/flink/pull/23777#discussion_r1403378092
########## flink-connectors/flink-connector-datagen/src/main/java/org/apache/flink/connector/datagen/functions/IndexLookupGeneratorFunction.java: ########## @@ -0,0 +1,180 @@ +/* + * 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.connector.datagen.functions; + +import org.apache.flink.annotation.Internal; +import org.apache.flink.annotation.VisibleForTesting; +import org.apache.flink.api.common.ExecutionConfig; +import org.apache.flink.api.common.typeinfo.TypeInformation; +import org.apache.flink.api.common.typeutils.TypeSerializer; +import org.apache.flink.api.connector.source.SourceReaderContext; +import org.apache.flink.connector.datagen.source.GeneratorFunction; +import org.apache.flink.core.memory.DataInputView; +import org.apache.flink.core.memory.DataInputViewStreamWrapper; +import org.apache.flink.core.memory.DataOutputViewStreamWrapper; +import org.apache.flink.util.Preconditions; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import javax.annotation.Nullable; + +import java.io.ByteArrayInputStream; +import java.io.ByteArrayOutputStream; +import java.io.EOFException; +import java.io.IOException; +import java.util.HashMap; +import java.util.Map; +import java.util.NoSuchElementException; + +/** + * A stream generator function that returns elements from the collection based on their index. + * + * <p>This generator function serializes the elements using Flink's type information. That way, any + * object transport using Java serialization will not be affected by the serializability of the + * elements. + * + * @param <OUT> The type of elements returned by this function. + */ +@Internal +public class IndexLookupGeneratorFunction<OUT> implements GeneratorFunction<Long, OUT> { + + private static final long serialVersionUID = 1L; + + private static final Logger LOG = LoggerFactory.getLogger(IndexLookupGeneratorFunction.class); + + /** The (de)serializer to be used for the data elements. */ + private final TypeSerializer<OUT> serializer; + + /** The actual data elements, in serialized form. */ + private byte[] elementsSerialized; + + private int numElements; + + private transient DataInputView input; + + private transient Map<Long, OUT> lookupMap; + + public IndexLookupGeneratorFunction(TypeInformation<OUT> typeInfo, Iterable<OUT> elements) { + this(typeInfo, new ExecutionConfig(), elements); + } + + public IndexLookupGeneratorFunction( + TypeInformation<OUT> typeInfo, ExecutionConfig config, Iterable<OUT> elements) { + // must not have null elements and mixed elements + checkIterable(elements, typeInfo.getTypeClass()); + this.serializer = typeInfo.createSerializer(config); + trySerialize(elements); + } + + @VisibleForTesting + @Nullable + public TypeSerializer<OUT> getSerializer() { + return serializer; + } + + private void serializeElements(Iterable<OUT> elements) throws IOException { + Preconditions.checkState(serializer != null, "serializer not set"); + LOG.info("Serializing elements using " + serializer); + ByteArrayOutputStream baos = new ByteArrayOutputStream(); + DataOutputViewStreamWrapper wrapper = new DataOutputViewStreamWrapper(baos); + + try { + for (OUT element : elements) { + serializer.serialize(element, wrapper); + } + } catch (Exception e) { + throw new IOException("Serializing the source elements failed: " + e.getMessage(), e); + } + this.elementsSerialized = baos.toByteArray(); + } Review Comment: After https://github.com/apache/flink/pull/23553 finally get's merged I will most likely simply extend FromElementsGeneratorFunction - it contains the same functionality. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
