Class SlotRef

fe/src/main/java/org/apache/impala/analysis/SlotRef.java:45–498

import com.google.common.collect.Iterables;

public class SlotRef extends Expr {
  protected List<String> rawPath_;
  protected final String label_;  // printed in toSql()

  // Results of analysis.
  protected SlotDescriptor desc_;

  // The resolved path after resolving 'rawPath_'.
  protected Path resolvedPath_ = null;

  // Indicates if this SlotRef is coming from zipping unnest where the unnest is given in
  // the FROM clause. Note, when the unnest is in the select list then an UnnestExpr
  // would be used instead of a SlotRef.
  protected boolean isZippingUnnest_ = false;

  public SlotRef(List<String> rawPath) {
    super();
    rawPath_ = rawPath;
    label_ = ToSqlUtils.getPathSql(rawPath_);
  }

  /**
   * C'tor for a "dummy" SlotRef used in substitution maps.
   */
  public SlotRef(String alias) {
    super();
    rawPath_ = null;
    // Relies on the label_ being compared in equals().
    label_ = ToSqlUtils.getIdentSql(alias.toLowerCase());
  }

  /**
   * C'tor for a "pre-analyzed" ref to a slot.
   */
  public SlotRef(SlotDescriptor desc) {
    super();
    if (desc.isScanSlot()) {
      resolvedPath_ = desc.getPath();
      rawPath_ = resolvedPath_.getRawPath();
    } else {
      rawPath_ = null;
    }
    desc_ = desc;
    type_ = desc.getType();
    evalCost_ = SLOT_REF_COST;
    String alias = desc.getParent().getAlias();
    label_ = (alias != null ? alias + "." : "") + desc.getLabel();
    numDistinctValues_ = adjustNumDistinctValues();

    if (type_.isStructType()) addStructChildrenAsSlotRefs();

    analysisDone();
  }

  /**
   * C'tor for cloning.
   */
  protected SlotRef(SlotRef other) {