/**
* Set the local variable to the given value. If the value is null, then the corresponding
* variable will be removed. If there is a global variable of the same name, then an
* EvaluationException will be thrown.
*
* @param name name of the local variable
* @param terms terms used to dereference the variable, or null if the variable is to be used
* directly
* @param value value to use or null to remove the variable
* @throws EvaluationException if there is a global variable with the same name as the local
* variable
*/
public void setLocalVariable(String name, Term[] terms, Element value)
throws EvaluationException {
assert (name != null);
if (terms == null || terms.length == 0) {
// Revert back to the simple case that does not require
// dereferencing.
setLocalVariable(name, value);
} else {
// The more complicated case where we need to dereference the
// variable. (And also possibly create the parents.)
// Retrieve the value of the local variable.
Element var = getLocalVariable(name);
// If the value is a protected resource, then make a shallow copy
// and replace the value of the local variable.
if (var != null && var.isProtected()) {
var = var.writableCopy();
setLocalVariable(name, var);
}
// If the value does not exist, create a resource of the correct
// type and insert into variable table.
if (var == null || var instanceof Undef) {
Term term = terms[0];
if (term.isKey()) {
var = new HashResource();
} else {
var = new ListResource();
}
setLocalVariable(name, var);
}
// Recursively descend to set the value.
assert (var != null);
try {
var.rput(terms, 0, value);
} catch (InvalidTermException ite) {
throw new EvaluationException(ite.formatVariableMessage(name, terms));
}
}
}
public boolean executeDmlValidationBlock(Operation dml, Element self) throws ValidationException {
Element result = null;
// Store the old local variables and iterators. Needed because structure
// templates need to keep the state across template.execute() calls.
LocalVariableMap oldVariables = createLocalVariableMap(null);
IteratorMap oldIterators = createIteratorMap();
// Initialize the SELF reference to the local self value.
SelfHolder selfHolder = new ReadOnlySelfHolder(self);
initializeSelfHolder(selfHolder);
try {
result = dml.execute(this);
} catch (ReturnValueException rve) {
result = rve.getElement();
} catch (EvaluationException ee) {
File objectFile = (objectTemplate != null) ? objectTemplate.source : null;
ValidationException ve =
ValidationException.create(MSG_VALIDATION_FAILED_BECAUSE_OF_EXCEPTION);
ve.setObjectTemplate(objectFile);
ve.initCause(ee);
throw ve;
} finally {
clearSelf();
restoreLocalVariableMap(oldVariables);
restoreIteratorMap(oldIterators);
}
try {
BooleanProperty bresult = (BooleanProperty) result;
return bresult.getValue().booleanValue();
} catch (ClassCastException cce) {
File objectFile = (objectTemplate != null) ? objectTemplate.source : null;
ValidationException ve =
ValidationException.create(
MSG_INVALID_VALIDATION_FUNCTION_RETURN_TYPE, result.getTypeAsString());
throw ve.setObjectTemplate(objectFile);
}
}
/**
* Return the Element which corresponds to the given variable name. It will first check local
* variables and then the parent context. This method will return null if the variable doesn't
* exist or the argument is null. Note that this will clone the final value, if it originated from
* a global variable.
*
* @param name name of the variable to lookup
* @param lookupOnly flag indicating if only a lookup should be done
* @param terms values for dereferencing the given variable
* @return Element value of the associated dereferenced variable
*/
public Element dereferenceVariable(String name, boolean lookupOnly, Term[] terms)
throws InvalidTermException {
boolean duplicate = false;
Element result = localVariables.get(name);
// If the result is null, then try to look up a global variable.
if (result == null) {
duplicate = true;
result = getGlobalVariable(name);
}
// Now actually dereference the given variable. The caller must deal
// with any invalid term exceptions or evaluation exceptions. We just
// pass those on.
if (result != null) {
if (!(result instanceof Undef)) {
// FIXME: Determine if the result needs to be protected.
result = result.rget(terms, 0, false, lookupOnly);
} else {
// Trying to dereference an undefined value. Therefore, the
// value does not exist; return null to caller.
result = null;
}
}
// FIXME: This is inefficient and should be avoided. However, one must
// ensure that global variables are protected against changes.
// To ensure that global variables are not inadvertently modified via
// copies in local variables, duplicate the result. Do this only AFTER
// the dereference to limit the amount of potentially unnecessary
// cloning.
if (duplicate && result != null) {
result = result.duplicate();
}
return result;
}
