this.sourceColumn = sourceColumn; this.resultColumn = resultColumn; this.requiredDeclarations = requiredDeclarations; this.accumulator = accumulator;
this( sourceColumn, resultColumn, new Declaration[0], new Declaration[0], null);
    public Accumulate(final Column sourceColumn,                      final Column resultColumn,                      final Declaration[] requiredDeclarations,                      final Accumulator accumulator) {        this.sourceColumn = sourceColumn;        this.resultColumn = resultColumn;        this.requiredDeclarations = requiredDeclarations;        this.accumulator = accumulator;    }