import org.apache.calcite.rel.RelCollationImpl; //导入依赖的package包/类
public static RelNode convert(Order order, ConversionContext context) throws InvalidRelException{

    // if there are compound expressions in the order by, we need to convert into projects on either side.
    RelNode input = context.toRel(order.getInput());
    List<String> fields = input.getRowType().getFieldNames();

    // build a map of field names to indices.
    Map<String, Integer> fieldMap = Maps.newHashMap();
    int i =0;
    for(String field : fields){
      fieldMap.put(field, i);
      i++;
    }

    List<RelFieldCollation> collations = Lists.newArrayList();

    for(Ordering o : order.getOrderings()){
      String fieldName = ExprHelper.getFieldName(o.getExpr());
      int fieldId = fieldMap.get(fieldName);
      RelFieldCollation c = new RelFieldCollation(fieldId, o.getDirection(), o.getNullDirection());
    }
    return new DrillSortRel(context.getCluster(), context.getLogicalTraits(), input, RelCollationImpl.of(collations));
  }
 

import org.apache.calcite.rel.RelCollationImpl; //导入依赖的package包/类
public static RelNode convert(Order order, ConversionContext context) throws InvalidRelException{

    // if there are compound expressions in the order by, we need to convert into projects on either side.
    RelNode input = context.toRel(order.getInput());
    List<String> fields = input.getRowType().getFieldNames();

    // build a map of field names to indices.
    Map<String, Integer> fieldMap = Maps.newHashMap();
    int i =0;
    for(String field : fields){
      fieldMap.put(field, i);
      i++;
    }

    List<RelFieldCollation> collations = Lists.newArrayList();

    for(Ordering o : order.getOrderings()){
      String fieldName = ExprHelper.getFieldName(o.getExpr());
      int fieldId = fieldMap.get(fieldName);
      RelFieldCollation c = new RelFieldCollation(fieldId, o.getDirection(), o.getNullDirection());
    }
    return new SortRel(context.getCluster(), context.getLogicalTraits(), input, RelCollationImpl.of(collations));
  }
 

import org.apache.calcite.rel.RelCollationImpl; //导入依赖的package包/类
private RelCollation getCollation(List<Integer> keys){
  List<RelFieldCollation> fields = Lists.newArrayList();
  for (int key : keys) {
    fields.add(new RelFieldCollation(key));
  }
  return RelCollationImpl.of(fields);
}
 

import org.apache.calcite.rel.RelCollationImpl; //导入依赖的package包/类
private RelCollation getCollation(DrillAggregateRel rel){

    List<RelFieldCollation> fields = Lists.newArrayList();
    for (int group : BitSets.toIter(rel.getGroupSet())) {
      fields.add(new RelFieldCollation(group));
    }
    return RelCollationImpl.of(fields);
  }
 

import org.apache.calcite.rel.RelCollationImpl; //导入依赖的package包/类
private RelCollation convertRelCollation(RelCollation src, Map<Integer, Integer> inToOut) {
  List<RelFieldCollation> newFields = Lists.newArrayList();

  for ( RelFieldCollation field : src.getFieldCollations()) {
    if (inToOut.containsKey(field.getFieldIndex())) {
      newFields.add(new RelFieldCollation(inToOut.get(field.getFieldIndex()), field.getDirection(), field.nullDirection));
    }
  }

  if (newFields.isEmpty()) {
    return RelCollationImpl.of();
  } else {
    return RelCollationImpl.of(newFields);
  }
}
 

import org.apache.calcite.rel.RelCollationImpl; //导入依赖的package包/类
/**
 * Create a RelCollation that has partition-by as the leading keys followed by order-by keys
 * @param window The window specification
 * @return a RelCollation with {partition-by keys, order-by keys}
 */
private RelCollation getCollation(Window.Group window) {
  List<RelFieldCollation> fields = Lists.newArrayList();
  for (int group : BitSets.toIter(window.keys)) {
    fields.add(new RelFieldCollation(group));
  }

  for (RelFieldCollation field : window.orderKeys.getFieldCollations()) {
    fields.add(field);
  }

  return RelCollationImpl.of(fields);
}
 

import org.apache.calcite.rel.RelCollationImpl; //导入依赖的package包/类
private RelCollation getCollation(AggregateRel rel){

    List<RelFieldCollation> fields = Lists.newArrayList();
    for (int group = 0; group < rel.getGroupSet().cardinality(); group++) {
      fields.add(new RelFieldCollation(group));
    }
    return RelCollationImpl.of(fields);
  }
 

import org.apache.calcite.rel.RelCollationImpl; //导入依赖的package包/类
public BeamSortRel(
    RelOptCluster cluster,
    RelTraitSet traits,
    RelNode child,
    RelCollation collation,
    RexNode offset,
    RexNode fetch) {
  super(cluster, traits, child, collation, offset, fetch);

  List<RexNode> fieldExps = getChildExps();
  RelCollationImpl collationImpl = (RelCollationImpl) collation;
  List<RelFieldCollation> collations = collationImpl.getFieldCollations();
  for (int i = 0; i < fieldExps.size(); i++) {
    RexNode fieldExp = fieldExps.get(i);
    RexInputRef inputRef = (RexInputRef) fieldExp;
    fieldIndices.add(inputRef.getIndex());
    orientation.add(collations.get(i).getDirection() == RelFieldCollation.Direction.ASCENDING);

    RelFieldCollation.NullDirection rawNullDirection = collations.get(i).nullDirection;
    if (rawNullDirection == RelFieldCollation.NullDirection.UNSPECIFIED) {
      rawNullDirection = collations.get(i).getDirection().defaultNullDirection();
    }
    nullsFirst.add(rawNullDirection == RelFieldCollation.NullDirection.FIRST);
  }

  if (fetch == null) {
    throw new UnsupportedOperationException("ORDER BY without a LIMIT is not supported!");
  }

  RexLiteral fetchLiteral = (RexLiteral) fetch;
  count = ((BigDecimal) fetchLiteral.getValue()).intValue();

  if (offset != null) {
    RexLiteral offsetLiteral = (RexLiteral) offset;
    startIndex = ((BigDecimal) offsetLiteral.getValue()).intValue();
  }
}
 

import org.apache.calcite.rel.RelCollationImpl; //导入依赖的package包/类
public Object toJson(RelCollationImpl node) {
  final List<Object> list = new ArrayList<Object>();
  for (RelFieldCollation fieldCollation : node.getFieldCollations()) {
    final Map<String, Object> map = jsonBuilder.map();
    map.put("field", fieldCollation.getFieldIndex());
    map.put("direction", fieldCollation.getDirection().name());
    map.put("nulls", fieldCollation.nullDirection.name());
    list.add(map);
  }
  return list;
}