Bug 189706 Enhance computed column aggregation function handling in UI.
Due to the issue discussed in 189705, current computed column aggregation builder in data set editor has bugs to extend: 1.When new a computed column, the aggregation argument field cannot be correctly set. 2.The argument field cannot be correct grayed out when user select a aggregation function without arguments 3.The available aggregation function list is incomprehensive 4.Some aggregation function cannot be set to model(say, weightedAve).
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/executor/transform/pass/DataSetProcessUtil.java
import org.eclipse.birt.data.engine.aggregation.AggregationFactory;
import org.eclipse.birt.data.engine.api.IBaseExpression;
import org.eclipse.birt.data.engine.api.aggregation.IAggregation;
import org.eclipse.birt.data.engine.api.querydefn.ComputedColumn;
import org.eclipse.birt.data.engine.core.DataException;
import org.eclipse.birt.data.engine.executor.aggregation.AggrDefnManager;
import org.eclipse.birt.data.engine.executor.aggregation.AggrInfo;
import org.eclipse.birt.data.engine.executor.aggregation.AggregationHelper;
import org.eclipse.birt.data.engine.executor.transform.OdiResultSetWrapper;
import org.eclipse.birt.data.engine.executor.transform.ResultSetPopulator;
import org.eclipse.birt.data.engine.executor.transform.TransformationConstants;
import org.eclipse.birt.data.engine.expression.ExpressionCompiler;
import org.eclipse.birt.data.engine.impl.ComputedColumnHelper;
import org.eclipse.birt.data.engine.impl.DataEngineSession;
import org.eclipse.birt.data.engine.impl.FilterByRow;
import org.eclipse.birt.data.engine.odi.IAggrInfo;
import org.mozilla.javascript.Context;
/**
 * The class used to populate DataSet data.
 * 
 */
class DataSetProcessUtil extends RowProcessUtil
{
	/**
	 * 
	 * @param populator
	 * @param iccState
	 * @param computedColumnHelper
	 * @param filterByRow
	 * @param psController