Examples with NotExpression net.sf.jsqlparser.expression.NotExpression used on opensource projects

Example 1 with NotExpression

use of net.sf.jsqlparser.expression.NotExpression in project JSqlParser by JSQLParser.

the class CNFConverter method handleNot.

/**
 * This function mainly deals with pushing not operators down.
 * check the child. If it is not a logic operator(and or or).
 * stop at that point. Else use De Morgan law to push not downwards.
 * @param index the index of the children appeared in parents array.
 */
private void handleNot(int index) {
    child = ((NotExpression) temp1).getExpression();
    // takes down the number of not operators.
    int nums = 1;
    while (child instanceof NotExpression) {
        child = ((NotExpression) child).getExpression();
        nums++;
    }
    /* if the number of not operators are even. we could get
         * rid of all the not operators. set the child to the parent. */
    if (nums % 2 == 0) {
        ((MultipleExpression) temp2).setChild(index, child);
        temp1 = child;
        pushNot(-1);
    } else {
        /* otherwise there will be one not left to push. 
             * if the child is not these two types of operators.
             * that means we reach the leaves of the logical part.
             * set a new not operator whose child is the current one
             * and connect that operator with the parent and return. */
        if (!(child instanceof MultiAndExpression) && !(child instanceof MultiOrExpression)) {
            if (child instanceof LikeExpression) {
                ((LikeExpression) child).setNot(true);
            } else if (child instanceof BinaryExpression) {
                ((BinaryExpression) child).setNot();
            } else {
                child = new NotExpression(child);
            }
            ((MultipleExpression) temp2).setChild(index, child);
            return;
        } else if (child instanceof MultiAndExpression) {
            MultiAndExpression and = (MultiAndExpression) child;
            List<Expression> list = new ArrayList<Expression>();
            for (int i = 0; i < and.size(); i++) {
                /* push not to every element in the operator. */
                NotExpression not = new NotExpression(and.getChild(i));
                list.add(not);
            }
            /* the De Morgan law shows we need to change and to or. */
            temp1 = new MultiOrExpression(list);
            ((MultipleExpression) temp2).setChild(index, temp1);
            pushNot(-1);
        } else if (child instanceof MultiOrExpression) {
            MultiOrExpression or = (MultiOrExpression) child;
            List<Expression> list = new ArrayList<Expression>();
            for (int i = 0; i < or.size(); i++) {
                /* push not to every element in the operator. */
                NotExpression not = new NotExpression(or.getChild(i));
                list.add(not);
            }
            /* the De Morgan law shows we need to change or to and. */
            temp1 = new MultiAndExpression(list);
            ((MultipleExpression) temp2).setChild(index, temp1);
            pushNot(-1);
        }
    }
}

Example 2 with NotExpression

use of net.sf.jsqlparser.expression.NotExpression in project JSqlParser by JSQLParser.

the class CloneHelper method modify.

/**
 * This method is used for changing the logical structure of the tree.
 * The main method is to convert and operator and or operator to let
 * them have multiple children (reflected in MultipleExpression.java
 * from the conditional package). Note if the value from the conditional
 * operator has a not attached to it we need to append an not operator
 * ahead of it since the not operator needed to be pushed down during
 * the second step. Also, I will leave out all the parenthesis expression
 * which is connected to the conditional operator.
 * @param express the expression that will be modified
 * @return the modified expression.
 */
public Expression modify(Expression express) {
    if (express instanceof NotExpression) {
        return new NotExpression(modify(((NotExpression) express).getExpression()));
    }
    if (express instanceof Parenthesis) {
        Parenthesis parenthesis = (Parenthesis) express;
        Expression result = modify(parenthesis.getExpression());
        if (parenthesis.isNot()) {
            return new NotExpression(result);
        }
        return result;
    }
    if (express instanceof AndExpression) {
        AndExpression and = (AndExpression) express;
        List<Expression> list = new ArrayList<Expression>();
        list.add(modify(and.getLeftExpression()));
        list.add(modify(and.getRightExpression()));
        MultiAndExpression result = new MultiAndExpression(list);
        if (and.isNot()) {
            return new NotExpression(result);
        }
        return result;
    }
    if (express instanceof OrExpression) {
        OrExpression or = (OrExpression) express;
        List<Expression> list = new ArrayList<Expression>();
        list.add(modify(or.getLeftExpression()));
        list.add(modify(or.getRightExpression()));
        MultiOrExpression result = new MultiOrExpression(list);
        if (or.isNot()) {
            return new NotExpression(result);
        }
        return result;
    }
    if (express instanceof BinaryExpression) {
        BinaryExpression binary = (BinaryExpression) express;
        if (binary.isNot()) {
            binary.removeNot();
            return new NotExpression(modify(binary));
        }
    }
    /* at this stage, there is no need to modify, just simply return. */
    return express;
}