SummationGroupBySummaryProvider.java

package org.eclipse.nebula.widgets.nattable.extension.glazedlists.groupBy.summary;

import java.util.List;

import org.eclipse.nebula.widgets.nattable.data.IColumnAccessor;

public class SummationGroupBySummaryProvider<T> implements
        IGroupBySummaryProvider<T> {

    private final IColumnAccessor<T> columnAccessor;

    public SummationGroupBySummaryProvider(IColumnAccessor<T> columnAccessor) {
        this.columnAccessor = columnAccessor;
    }

    @Override
    public Object summarize(int columnIndex, List<T> children) {
        double summaryValue = 0;
        for (T child : children) {
            Object dataValue = this.columnAccessor.getDataValue(child, columnIndex);
            if (dataValue instanceof Number) {
                summaryValue += ((Number) dataValue).doubleValue();
            }
        }

        return summaryValue;
    }

}