public class QueryParsing {
  public static final String OP = "q.op";  // the SolrParam used to override the QueryParser "default operator"
  public static final String V = "v";      // value of this parameter
  public static final String F = "f";      // field that a query or command pertains to
  public static final String TYPE = "type";// type of this query or command
  public static final String DEFTYPE = "defType"; // default type for any direct subqueries
  public static final String LOCALPARAM_START = "{!";
  public static final char LOCALPARAM_END = '}';
  public static final String DOCID = "_docid_";
  public static final String SCORE = "score";

  // true if the value was specified by the "v" param (i.e. v=myval, or v=$param)
  public static final String VAL_EXPLICIT = "__VAL_EXPLICIT__";


  /**
   * Returns the "prefered" default operator for use by Query Parsers, 
   * based on the settings in the IndexSchema which may be overridden using 
   * an optional String override value.
   *
   * @see IndexSchema#getQueryParserDefaultOperator()
   * @see #OP
   */
  public static Operator getQueryParserDefaultOperator(final IndexSchema sch, 
                                                       final String override) {
    String val = override;
    if (null == val) val = sch.getQueryParserDefaultOperator();
    return "AND".equals(val) ? Operator.AND : Operator.OR;
  }

  // ...
}