function(sPropertyName) {
			var oResult = null;
			for (var i = -1, oCurrentSorter; (oCurrentSorter = this._aSortCondition[++i]) !== undefined;) {
				if (oCurrentSorter.property.name === sPropertyName) {
					oResult = {
						sorter : oCurrentSorter,
						index : i
					};
					break;
				}
			}
			return oResult;
		}
function(sPropertyName) {
			var oResult = null;
			for (var i = -1, oCurrentSorter; (oCurrentSorter = this._aSortCondition[++i]) !== undefined;) {
				if (oCurrentSorter.property.name === sPropertyName) {
					oResult = {
						sorter : oCurrentSorter,
						index : i
					};
					break;
				}
			}
			return oResult;
		}
function ( sPropertyName ) { var oResult = null ; for ( var i = - 1 , oCurrentSorter ; ( oCurrentSorter = this . _aSortCondition [ ++ i ] ) !== undefined ; ) { if ( oCurrentSorter . property . name === sPropertyName ) { oResult = { sorter : oCurrentSorter , index : i } ; break ; } } return oResult ; }
Checks if an order by expression for the given property is already
defined and returns a reference to an object with property sorter and
index of the object or null if the property is not yet defined in an
order by expression.

@private
Checks if an order by expression for the given property is already defined and returns a reference to an object with property sorter and index of the object or null if the property is not yet defined in an order by expression .
Returns the highest priority sorting condition for the given property name.