/**
* Gets the right hand expression as a valid value to be assigned to the left hand side. Usually
* returns the original rhs. However, if the lhs is of a primitive type, and the rhs is an
* explicit null, returns a primitive value instead.
*/
private Expression rhsAsValue() {
if (SqlTypeUtil.isJavaPrimitive(lhsType) && (rhsType.getSqlTypeName() == SqlTypeName.NULL)) {
if (lhsType.getSqlTypeName() == SqlTypeName.BOOLEAN) {
return Literal.constantFalse();
} else {
return Literal.constantZero();
}
}
return rhsExp;
}
/**
* Generates code to round an expression according to the Farrago convention. The Farrago
* convention is to round away from zero. Rounding is performed with the following algorithm.
*
* <pre>
* in = rhs;
* if (value < 0) {
* in = -in;
* out = Math.round(in);
* out = -out;
* } else {
* out = Math.round(in);
* }
* </pre>
*
* <p>PRECONDITION: rhsExp must be an unwrapped (not null) Java primitive
*
* <p>TODO: account for overflow in both unary minus and round.
*/
private Expression roundAway() {
// Get the primitive part of right hand side
RelDataType inType = translator.getTypeFactory().createTypeWithNullability(rhsType, false);
// TODO: is there any preference between stack and instance var?
OJClass inClass = getClass(inType);
Variable inTemp = translator.getRelImplementor().newVariable();
translator.addStatement(declareStackVar(inClass, inTemp, rhsExp));
OJClass outClass = getLhsClass();
Variable outTemp = translator.getRelImplementor().newVariable();
translator.addStatement(declareStackVar(outClass, outTemp, null));
boolean isLong =
translator.getFarragoTypeFactory().getClassForPrimitive(lhsType) == long.class;
addStatement(
new IfStatement(
new BinaryExpression(inTemp, BinaryExpression.LESS, Literal.constantZero()),
new StatementList(
assign(inTemp, minus(inClass, inTemp)),
assign(outTemp, round(lhsClass, inTemp, isLong)),
assign(outTemp, minus(outClass, outTemp))),
new StatementList(assign(outTemp, round(lhsClass, inTemp, isLong)))));
return outTemp;
}
/**
* Implements a cast from any Java primitive to a nullable Java primitive as a simple
* assignment. i.e.
*
* <pre>
* [NullablePrimitiveType] lhs;
* lhs.[nullIndicator] = ...;
* if (! lhs.[nullIndicator]) {
* // check overflow ...
* // round ...
* lhs.[value] = ...;
* }
* </pre>
*/
private Expression castPrimitiveToNullablePrimitive() {
ensureLhs();
boolean nullableSource = rhsType.isNullable();
Expression rhsIsNull;
if (nullableSource) {
rhsIsNull = getNullIndicator(rhsExp);
rhsExp = getValue(rhsType, rhsExp);
} else {
rhsIsNull = Literal.constantFalse();
}
addStatement(assign(getNullIndicator(lhsExp), rhsIsNull));
StatementList setValueBlock = new StatementList();
StatementList oldList = borrowStmtList(setValueBlock);
try {
checkOverflow();
roundAsNeeded();
addStatement(assign(getValue(lhsType, lhsExp), new CastExpression(getLhsClass(), rhsExp)));
} finally {
returnStmtList(oldList);
}
if (nullableSource) {
addStatement(new IfStatement(not(getNullIndicator(lhsExp)), setValueBlock));
} else {
addStatementList(setValueBlock);
}
return lhsExp;
}
/** Generates code to throw an exception when a NULL value is casted to a NOT NULL type */
private void checkNotNull() {
if (!lhsType.isNullable() && rhsType.isNullable()) {
rhsExp = rhsAsJava();
addStatement(
new ExpressionStatement(
new MethodCall(
translator.getRelImplementor().getConnectionVariable(),
"checkNotNull",
new ExpressionList(Literal.makeLiteral(targetName), rhsExp))));
}
}
private Expression castToAssignableValueImpl() {
if (requiresSpecializedCast()) {
if (rhsType.isNullable() && (!SqlTypeUtil.isDecimal(rhsType))) {
rhsExp = getValue(rhsType, rhsExp);
}
addStatement(
new ExpressionStatement(
new MethodCall(
lhsExp,
"cast",
new ExpressionList(rhsExp, Literal.makeLiteral(lhsType.getPrecision())))));
} else {
// Set current_date for casting time to timestamp. If
// rhsType is null then we may have to be ready for anything.
// But it will be null even for current_timestamp, so the
// condition below seems a bit excessive.
if ((lhsType.getSqlTypeName() == SqlTypeName.TIMESTAMP)
&& ((rhsType == null) || (rhsType.getSqlTypeName() == SqlTypeName.TIME))) {
addStatement(
new ExpressionStatement(
new MethodCall(lhsExp, "setCurrentDate", new ExpressionList(getCurrentDate()))));
}
addStatement(
new ExpressionStatement(
new MethodCall(
lhsExp, AssignableValue.ASSIGNMENT_METHOD_NAME, new ExpressionList(rhsExp))));
}
// Trim precision of datetime values.
//
if (((lhsType.getSqlTypeName() == SqlTypeName.TIMESTAMP)
|| (lhsType.getSqlTypeName() == SqlTypeName.TIME))) {
if ((rhsType != null)
// FIXME: JavaType(java.sql.Time) and
// JavaType(java.sql.Timestamp) say they support precision
// but do not.
&& !rhsType.toString().startsWith("JavaType(")
&& rhsType.getSqlTypeName().allowsPrec()
&& (lhsType.getPrecision() < rhsType.getPrecision())) {
int lhsPrecision = lhsType.getPrecision();
if (lhsPrecision == -1) {
lhsPrecision = 0;
}
addStatement(
new ExpressionStatement(
new MethodCall(
lhsExp,
SqlDateTimeWithoutTZ.ADJUST_PRECISION_METHOD_NAME,
new ExpressionList(Literal.makeLiteral(lhsPrecision)))));
}
}
boolean mayNeedPadOrTruncate = false;
if (SqlTypeUtil.inCharOrBinaryFamilies(lhsType) && !SqlTypeUtil.isLob(lhsType)) {
mayNeedPadOrTruncate = true;
}
if (mayNeedPadOrTruncate) {
// check overflow if it is datetime.
// TODO: should check it at the run time.
// so, it should be in the
// cast(SqlDateTimeWithTZ, int precision);
if ((rhsType != null) && (rhsType.getSqlTypeName() != null)) {
SqlTypeName typeName = rhsType.getSqlTypeName();
int precision = 0;
switch (typeName) {
case DATE:
precision = 10;
break;
case TIME:
precision = 8;
break;
case TIMESTAMP:
precision = 19;
break;
}
if ((precision != 0) && (precision > lhsType.getPrecision())) {
addStatement(
new IfStatement(
new BinaryExpression(
Literal.makeLiteral(precision),
BinaryExpression.GREATER,
Literal.makeLiteral(lhsType.getPrecision())),
getThrowStmtList()));
}
}
if ((rhsType != null)
&& (rhsType.getFamily() == lhsType.getFamily())
&& !SqlTypeUtil.isLob(rhsType)) {
// we may be able to skip pad/truncate based on
// known facts about source and target precisions
if (SqlTypeUtil.isBoundedVariableWidth(lhsType)) {
if (lhsType.getPrecision() >= rhsType.getPrecision()) {
// target precision is greater than source
// precision, so truncation is impossible
// and we can skip adjustment
return lhsExp;
}
} else {
if ((lhsType.getPrecision() == rhsType.getPrecision())
&& !SqlTypeUtil.isBoundedVariableWidth(rhsType)) {
// source and target are both fixed-width, and
// precisions are the same, so there's no adjustment
// needed
return lhsExp;
}
}
}
// determine target precision
Expression precisionExp = Literal.makeLiteral(lhsType.getPrecision());
// need to pad only for fixed width
Expression needPadExp = Literal.makeLiteral(!SqlTypeUtil.isBoundedVariableWidth(lhsType));
// pad character is 0 for binary, space for character
Expression padByteExp;
if (!SqlTypeUtil.inCharFamily(lhsType)) {
padByteExp = new CastExpression(OJSystem.BYTE, Literal.makeLiteral(0));
} else {
padByteExp = new CastExpression(OJSystem.BYTE, Literal.makeLiteral(' '));
}
// generate the call to do the job
addStatement(
new ExpressionStatement(
new MethodCall(
lhsExp,
BytePointer.ENFORCE_PRECISION_METHOD_NAME,
new ExpressionList(precisionExp, needPadExp, padByteExp))));
}
return lhsExp;
}