collector

ConceptSphere.java

package com.idolz.data.batch.dto;

import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import static java.util.stream.Collectors.toList;
import static java.util.stream.Collectors.mapping;
import static java.util.stream.Collectors.groupingBy;


import com.idolz.data.batch.model.content.Concept;
import com.idolz.data.batch.model.content.DataMapping;

import lombok.Getter;

@Getter
public class ConceptSphere {

  public ConceptSphere(List<DataThumbJsonDTO> dataThumbList, List<DataMapping> dataMappingList) {
    Map<String, List<Concept>> conceptBySeqIndex = dataMappingList.stream()
        .collect(groupingBy(DataMapping::getSeqIndex, mapping(DataMapping::getConcept, toList())));
    this.dataThumbList = dataThumbList.stream()
        .map(dataThumb -> mergeConcept(conceptBySeqIndex, dataThumb))
        .filter(Objects::nonNull)
        .collect(toList());
  }
  private List<DataThumbJsonDTO> dataThumbList;

  private DataThumbJsonDTO mergeConcept(Map<String, List<Concept>> conceptBySeqIndex, DataThumbJsonDTO dataThumbJsonDTO) {
    List<Concept> concepts = conceptBySeqIndex.getOrDefault(String.valueOf(dataThumbJsonDTO.getSeqIndex()), Collections
        .emptyList());
    return dataThumbJsonDTO.mergeWithConcept(concepts);
  }

}