ConcatAggregator

A ConcatAggregator is an Aggregator that concatenates string values by calling toString on the values, and appending the string values to an internal StringBuilder. It returns its value as a String. Optionally, a separator string may be specified to delimit string values. If no values were encountered, then the returned string is empty (""). This Aggregator does not use floating-point calculations, so it does not override the terminateDoubleDouble method.

Usage

Create and use a ConcatAggregator, with one of the following methods:

  • Aggregator agg = new ConcatAggregator("property");
  • Aggregator agg = new ConcatAggregator("property", ",");
  • Aggregator agg = Aggregator.getAggregator("Concat(property)");
  • Aggregator agg = Aggregator.getAggregator("Concat(property, \",\")");

There is no restriction on the type of property values expected. Any value found will have its "toString()" method called, to append the string to the result.

The string is built by appending the property value strings in the order in which jAgg finds them in the original list of values.