fun.mike.flapjack.pipeline.lab.GroupOutputContext Maven / Gradle / Ivy

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package fun.mike.flapjack.pipeline.lab;

import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.function.Function;

import fun.mike.record.alpha.Record;

public class GroupOutputContext implements OutputContext>> {
    private final Function groupBy;

    public GroupOutputContext(Function groupBy) {
        this.groupBy = groupBy;
    }

    @Override
    public OutputChannel>> buildChannel() {
        return new GroupOutputChannel<>(groupBy);
    }

    @Override
    public void accept(OutputContextVisitor visitor) {
        visitor.accept(this);
    }

    private final class GroupOutputChannel implements OutputChannel>> {
        private final Function groupBy;
        private final Map> values;

        public GroupOutputChannel(Function groupBy) {
            this.values = new HashMap<>();
            this.groupBy = groupBy;
        }

        @Override
        public Optional put(int number, String line, Record value) {
            try {
                G group = groupBy.apply(value);
                if (values.containsKey(group)) {
                    values.get(group).add(value);
                } else {
                    List groupValues = new LinkedList<>();
                    groupValues.add(value);
                    values.put(group, groupValues);
                }
                return Optional.empty();
            } catch (Exception ex) {
                return Optional.of(OutputFailure.build(number, line, value, ex));
            }
        }

        @Override
        public Map> getValue() {
            return values;
        }

        @Override
        public void close() {
        }
    }

}