package plan_runner.expressions;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import plan_runner.conversion.DoubleConversion;
import plan_runner.conversion.NumericConversion;
import plan_runner.conversion.TypeConversion;
import plan_runner.visitors.ValueExpressionVisitor;
/*
* This class implements Division between any Number type (Integer, Double, Long, etc.).
* It convert all the value to double, and then return the final result by automatic casting
* (i.e. (int)1.0 )
*
* Double can store integers exatly in binary representation,
* so we won't lose the precision on our integer operations.
*
* Having different T types in the constructor arguments
* does not result in exception in the constructor,
* but rather in eval method.
*/
public class Division implements ValueExpression<Double> {
private static final long serialVersionUID = 1L;
private final List<ValueExpression> _veList = new ArrayList<ValueExpression>();
private final NumericConversion<Double> _wrapper = new DoubleConversion();
public Division(ValueExpression ve1, ValueExpression ve2, ValueExpression... veArray) {
_veList.add(ve1);
_veList.add(ve2);
_veList.addAll(Arrays.asList(veArray));
}
@Override
public void accept(ValueExpressionVisitor vev) {
vev.visit(this);
}
@Override
public void changeValues(int i, ValueExpression<Double> newExpr) {
}
@Override
public Double eval(List<String> tuple) {
final ValueExpression firstVE = _veList.get(0);
final Object firstObj = firstVE.eval(tuple);
final NumericConversion firstType = (NumericConversion) firstVE.getType();
double result = firstType.toDouble(firstObj);
for (int i = 1; i < _veList.size(); i++) {
final ValueExpression currentVE = _veList.get(i);
final Object currentObj = currentVE.eval(tuple);
final NumericConversion currentType = (NumericConversion) currentVE.getType();
result /= currentType.toDouble(currentObj);
}
return _wrapper.fromDouble(result);
}
@Override
public String evalString(List<String> tuple) {
final Double result = eval(tuple);
return _wrapper.toString(result);
}
@Override
public List<ValueExpression> getInnerExpressions() {
return _veList;
}
@Override
public TypeConversion getType() {
return _wrapper;
}
@Override
public void inverseNumber() {
}
@Override
public boolean isNegative() {
return false;
}
@Override
public String toString() {
final StringBuilder sb = new StringBuilder();
for (int i = 0; i < _veList.size(); i++) {
sb.append("(").append(_veList.get(i)).append(")");
if (i != _veList.size() - 1)
sb.append(" / ");
}
return sb.toString();
}
}