protected RexNode register(RexNode expr) {
final String key = expr.toString();
final RexNode previous = mapDigestToExpr.put(key, expr);
if (!allowDups && (previous != null)) {
throw new SubExprExistsException(expr);
}
return expr;
}
/**
* Creates a key for {@link RexNode} which is the same as another key of another RexNode only if
* the two have both the same type and textual representation. For example, "10" integer and "10"
* bigint result in different keys.
*/
public static String makeKey(RexNode expr) {
String type = expr.getType().getFullTypeString();
String separator = ";";
String node = expr.toString();
StringBuilder keyBuilder =
new StringBuilder(type.length() + separator.length() + node.length());
keyBuilder.append(type).append(separator).append(node);
return keyBuilder.toString();
}
protected RexNode lookup(RexNode expr) {
return mapDigestToExpr.get(expr.toString());
}