public String convertToPostgres(Expression transformationFunctionExpression, boolean withRel) {
String functionExpression =
transformationFunctionExpression.getJepExpression().toStringForSql();
// first fix attribute names
for (VariablePathExpression vpe : transformationFunctionExpression.getAttributePaths()) {
if (functionExpression.contains(vpe.toString())) {
String expressionToCheckForSigns =
transformationFunctionExpression.getJepExpression().toString();
int startIndex = expressionToCheckForSigns.indexOf(vpe.toString());
int endIndex = startIndex + vpe.toString().length();
boolean castToFloat = false;
// check so that the String index will not get out of bounds
if (startIndex - 2 >= 0) {
if (math_sign.contains(expressionToCheckForSigns.charAt(startIndex - 2))) {
castToFloat = true;
}
// to catch the '>=' or '<=' case
else if (expressionToCheckForSigns.charAt(startIndex - 2) == '=' && startIndex - 3 >= 0) {
if (expressionToCheckForSigns.charAt(startIndex - 3) == '<'
|| expressionToCheckForSigns.charAt(startIndex - 3) == '>') {
castToFloat = true;
}
}
}
if (endIndex + 2 <= expressionToCheckForSigns.length()) {
if (math_sign.contains(expressionToCheckForSigns.charAt(endIndex + 1))) {
castToFloat = true;
}
}
String newAttrName;
// replace them with the corresponding attribute name
if (withRel) {
newAttrName = GenerateSQL.attributeNameWithVariable(vpe);
} else {
newAttrName = GenerateSQL.attributeNameInVariable(vpe);
}
// if previous or next character is one of {+,-,*,/,<,>} cast it to float
if (castToFloat) {
functionExpression =
functionExpression.replaceAll(vpe.toString(), "cast(" + newAttrName + " as float)");
} else {
functionExpression = functionExpression.replaceAll(vpe.toString(), newAttrName);
}
}
}
return replaceExpression(functionExpression);
}
private static String sqlString(Expression expression) {
String result = "";
List<VariablePathExpression> attributePaths = expression.getAttributePaths();
if (expression.toString().startsWith("isNull(")) {
String attributeName = extractAttributeNameFromExpression(attributePaths.get(0));
return attributeName + " IS NULL";
}
if (expression.toString().startsWith("isNotNull(")) {
String attributeName = extractAttributeNameFromExpression(attributePaths.get(0));
return attributeName + " IS NOT NULL";
}
for (VariablePathExpression attributePath : attributePaths) {
String attributeName = extractAttributeNameFromExpression(attributePaths.get(0));
result = expression.toString().replaceAll(attributePath.toString(), attributeName);
}
result = result.replaceAll("==", "=");
result = result.replaceAll("\"", "\'");
return result.replaceAll("&&", "AND");
}