/**
* Do code generation for this conversion of a value from the Java to the SQL domain.
*
* @param acb The ExpressionClassBuilder for the class we're generating
* @param mb the method the expression will go into
* @exception StandardException Thrown on error
*/
public void generateExpression(ExpressionClassBuilder acb, MethodBuilder mb)
throws StandardException {
TypeId resultType;
String resultTypeName;
/*
** Tell the Java node that it's value is being returned to the
** SQL domain. This way, it knows whether the checking for a null
** receiver is to be done at the Java level or the SQL level.
*/
javaNode.returnValueToSQLDomain();
/* Generate the receiver, if any. */
boolean hasReceiver = javaNode.generateReceiver(acb, mb);
/*
** If the java expression has a receiver, we want to check whether
** it's null before evaluating the whole expression (to avoid
** a NullPointerException.
*/
if (hasReceiver) {
/*
** There is a receiver. Generate a null SQL value to return
** in case the receiver is null. First, create a field to hold
** the null SQL value.
*/
String nullValueClass = getTypeCompiler().interfaceName();
LocalField nullValueField = acb.newFieldDeclaration(Modifier.PRIVATE, nullValueClass);
/*
** There is a receiver. Generate the following to test
** for null:
**
** (receiverExpression == null) ?
*/
mb.conditionalIfNull();
mb.getField(nullValueField);
acb.generateNullWithExpress(mb, getTypeCompiler(), getTypeServices().getCollationType());
/*
** We have now generated the expression to test, and the
** "true" side of the ?: operator. Finish the "true" side
** so we can generate the "false" side.
*/
mb.startElseCode();
}
resultType = getTypeId();
TypeCompiler tc = getTypeCompiler();
resultTypeName = tc.interfaceName();
/* Allocate an object for re-use to hold the result of the conversion */
LocalField field = acb.newFieldDeclaration(Modifier.PRIVATE, resultTypeName);
/* Generate the expression for the Java value under us */
javaNode.generateExpression(acb, mb);
/* Generate the SQL value, which is always nullable */
acb.generateDataValue(mb, tc, getTypeServices().getCollationType(), field);
/*
** If there was a receiver, the return value will be the result
** of the ?: operator.
*/
if (hasReceiver) {
mb.completeConditional();
}
}
