Examples with QueryFunction org.structr.core.function.QueryFunction used on opensource projects

Example 1 with QueryFunction

use of org.structr.core.function.QueryFunction in project structr by structr.

the class SliceExpression method evaluate.

@Override
public Object evaluate(final ActionContext ctx, final GraphObject entity) throws FrameworkException, UnlicensedException {
    if (listExpression == null || startExpression == null || endExpression == null) {
        return ERROR_MESSAGE_SLICE;
    }
    // evaluate start and end bounds
    final Object startObject = startExpression.evaluate(ctx, entity);
    final Object endObject = endExpression.evaluate(ctx, entity);
    if (startObject == null) {
        throw new FrameworkException(422, "Error in slice(): invalid start of range: null");
    }
    if (endObject == null) {
        throw new FrameworkException(422, "Error in slice(): invalid end of range: null");
    }
    final Integer start = toNumber(startObject);
    Integer end = toNumber(endObject);
    boolean valid = true;
    // null => number format parsing error or invalid source data
    if (start == null || end == null) {
        return null;
    }
    // check bounds BEFORE evaluating list expression
    if (start < 0) {
        valid = false;
        logger.warn("Error in slice(): start index must be >= 0.");
    }
    if (end < 0) {
        valid = false;
        logger.warn("Error in slice(): end index must be > 0.");
    }
    if (start >= end) {
        valid = false;
        logger.warn("Error in slice(): start index must be < end index.");
    }
    if (valid) {
        if (listExpression instanceof QueryFunction) {
            final QueryFunction queryFunction = (QueryFunction) listExpression;
            queryFunction.setRangeStart(start);
            queryFunction.setRangeEnd(end);
            return listExpression.evaluate(ctx, entity);
        } else if (listExpression instanceof FunctionExpression && ((FunctionExpression) listExpression).getFunction() instanceof QueryFunction) {
            final QueryFunction queryFunction = (QueryFunction) ((FunctionExpression) listExpression).getFunction();
            queryFunction.setRangeStart(start);
            queryFunction.setRangeEnd(end);
            return listExpression.evaluate(ctx, entity);
        } else {
            final Object src = listExpression.evaluate(ctx, entity);
            List list = null;
            // handle list argument
            if (src instanceof List) {
                list = (List) src;
            // handle array argument
            } else if (isArray(src)) {
                list = toList((Object[]) src);
            // handle collection argument
            } else if (src != null) {
                list = new LinkedList((Collection) src);
            } else {
                return null;
            }
            if (start > list.size()) {
                valid = false;
                logger.warn("Error in slice(): start index is out of range.");
            }
            if (end > list.size()) {
                end = list.size();
            }
            if (valid) {
                return list.subList(start, end);
            }
        }
    }
    return null;
}