static MinMaxInitCount join(MinMaxInitCount initCount1, MinMaxInitCount initCount2) {
if (initCount1 == null) {
return initCount2;
}
if (initCount2 == null) {
return initCount1;
}
MinMaxInitCount t =
new MinMaxInitCount(
InitCount.min(initCount1.getMin(), initCount2.getMin()),
InitCount.max(initCount1.getMax(), initCount2.getMax()));
return t;
}
/** Check that the assignment to a field is correct. */
protected void checkFieldAssign(
FlowGraph graph, FieldAssign a, DataFlowItem dfIn, DataFlowItem dfOut)
throws SemanticException {
Field f = (Field) a.left();
FieldInstance fi = f.fieldInstance();
if (fi.flags().isFinal()) {
if ((currCBI.currCodeDecl instanceof ConstructorDecl
|| currCBI.currCodeDecl instanceof Initializer)
&& isFieldsTargetAppropriate(f)) {
// we are in a constructor or initializer block and
// if the field is static then the target is the class
// at hand, and if it is not static then the
// target of the field is this.
// So a final field in this situation can be
// assigned to at most once.
MinMaxInitCount initCount = (MinMaxInitCount) dfOut.initStatus.get(fi);
if (InitCount.MANY.equals(initCount.getMax())) {
throw new SemanticException(
"field \"" + fi.name() + "\" might already have been assigned to", a.position());
}
} else {
// not in a constructor or intializer, or the target is
// not appropriate. So we cannot assign
// to a final field at all.
throw new SemanticException(
"Cannot assign a value " + "to final field \"" + fi.name() + "\"", a.position());
}
}
}
/** Check that the assignment to a local variable is correct. */
protected void checkLocalAssign(
FlowGraph graph, LocalAssign a, DataFlowItem dfIn, DataFlowItem dfOut)
throws SemanticException {
LocalInstance li = ((Local) a.left()).localInstance();
if (!currCBI.localDeclarations.contains(li)) {
throw new SemanticException(
"Final local variable \"" + li.name() + "\" cannot be assigned to in an inner class.",
a.position());
}
MinMaxInitCount initCount = (MinMaxInitCount) dfOut.initStatus.get(li);
if (li.flags().isFinal() && InitCount.MANY.equals(initCount.getMax())) {
throw new SemanticException(
"variable \"" + li.name() + "\" might already have been assigned to", a.position());
}
}
/** Perform the appropriate flow operations for assignment to a local variable */
protected Map flowLocalAssign(
DataFlowItem inItem, FlowGraph graph, LocalAssign a, Set succEdgeKeys) {
Local l = (Local) a.left();
Map m = new HashMap(inItem.initStatus);
MinMaxInitCount initCount = (MinMaxInitCount) m.get(l.localInstance());
// initcount could be null if the local is defined in the outer
// class, or if we have not yet seen its declaration (i.e. the
// local is used in its own initialization)
if (initCount == null) {
initCount = new MinMaxInitCount(InitCount.ZERO, InitCount.ZERO);
}
initCount = new MinMaxInitCount(initCount.getMin().increment(), initCount.getMax().increment());
m.put(l.localInstance(), initCount);
return itemToMap(new DataFlowItem(m), succEdgeKeys);
}
/** Perform the appropriate flow operations for assignment to a field */
protected Map flowFieldAssign(
DataFlowItem inItem, FlowGraph graph, FieldAssign a, Set succEdgeKeys) {
Field f = (Field) a.left();
FieldInstance fi = f.fieldInstance();
if (fi.flags().isFinal() && isFieldsTargetAppropriate(f)) {
// this field is final and the target for this field is
// appropriate for what we are interested in.
Map m = new HashMap(inItem.initStatus);
MinMaxInitCount initCount = (MinMaxInitCount) m.get(fi);
// initCount may be null if the field is defined in an
// outer class.
if (initCount != null) {
initCount =
new MinMaxInitCount(initCount.getMin().increment(), initCount.getMax().increment());
m.put(fi, initCount);
return itemToMap(new DataFlowItem(m), succEdgeKeys);
}
}
return null;
}