public void attach(
EventType parentEventType,
StatementContext statementContext,
ViewFactory optionalParentFactory,
List<ViewFactory> parentViewFactories)
throws ViewParameterException {
eventType = parentEventType;
String message =
NAME + " requires a numeric size parameter and a list of expressions providing sort keys";
if (viewParameters.size() < 2) {
throw new ViewParameterException(message);
}
ExprNode[] validated =
ViewFactorySupport.validate(NAME, parentEventType, statementContext, viewParameters, true);
for (int i = 1; i < validated.length; i++) {
ViewFactorySupport.assertReturnsNonConstant(NAME, validated[i], i);
}
ExprEvaluatorContextStatement exprEvaluatorContext =
new ExprEvaluatorContextStatement(statementContext);
Object sortSize =
ViewFactorySupport.evaluateAssertNoProperties(NAME, validated[0], 0, exprEvaluatorContext);
if ((sortSize == null) || (!(sortSize instanceof Number))) {
throw new ViewParameterException(message);
}
sortWindowSize = ((Number) sortSize).intValue();
sortCriteriaExpressions = new ExprNode[validated.length - 1];
isDescendingValues = new boolean[sortCriteriaExpressions.length];
for (int i = 1; i < validated.length; i++) {
if (validated[i] instanceof ExprOrderedExpr) {
isDescendingValues[i - 1] = ((ExprOrderedExpr) validated[i]).isDescending();
sortCriteriaExpressions[i - 1] = validated[i].getChildNodes().get(0);
} else {
sortCriteriaExpressions[i - 1] = validated[i];
}
}
}
