Github user StefanRRichter commented on a diff in the pull request: https://github.com/apache/flink/pull/6196#discussion_r198113448 --- Diff: flink-core/src/main/java/org/apache/flink/api/common/typeutils/CompositeSerializer.java --- @@ -0,0 +1,204 @@ +package org.apache.flink.api.common.typeutils; + +import org.apache.flink.api.java.tuple.Tuple2; +import org.apache.flink.core.memory.DataInputView; +import org.apache.flink.core.memory.DataOutputView; +import org.apache.flink.util.Preconditions; + +import java.io.IOException; +import java.util.ArrayList; +import java.util.List; +import java.util.stream.Collectors; +import java.util.stream.IntStream; + +/** + * Base class for composite serializers. + * + * <p>This class serializes a list of objects + * + * @param <T> type of custom serialized value + */ +@SuppressWarnings("unchecked") +public abstract class CompositeSerializer<T> extends TypeSerializer<T> { + private final List<TypeSerializer> originalSerializers; + + protected CompositeSerializer(List<TypeSerializer> originalSerializers) { + Preconditions.checkNotNull(originalSerializers); + this.originalSerializers = originalSerializers; + } + + protected abstract T composeValue(List values); --- End diff -- Also here, list is just used as raw type. I think also the abstract methods could use some documentation for people that would like to create new subclasses in the future.
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