/**
* A restricted version of areClassTypesAssignable that is used for comparing the type arguments
* of parameterized types, where the lhsTypeArg is the container.
*/
private static boolean doesTypeArgumentContain(JClassType lhsTypeArg, JClassType rhsTypeArg) {
if (lhsTypeArg == rhsTypeArg) {
return true;
}
// Check for wildcard types
JWildcardType lhsWildcard = lhsTypeArg.isWildcard();
JWildcardType rhsWildcard = rhsTypeArg.isWildcard();
if (lhsWildcard != null) {
if (rhsWildcard != null) {
return areWildcardsAssignable(lhsWildcard, rhsWildcard);
} else {
// LHS is a wildcard but the RHS is not.
if (lhsWildcard.getLowerBounds().length > 0) {
return areClassTypesAssignable(rhsTypeArg, lhsWildcard.getFirstBound());
} else {
return areClassTypesAssignable(lhsWildcard.getFirstBound(), rhsTypeArg);
}
}
}
/*
* At this point the arguments are not the same and they are not wildcards
* so, they cannot be assignable, Eh.
*/
return false;
}
/**
* Returns <code>true</code> if the rhsWildcard can be assigned to the lhsWildcard. This method
* does not consider supertypes of either lhs or rhs.
*/
private static boolean areWildcardsAssignable(
JWildcardType lhsWildcard, JWildcardType rhsWildcard) {
// areClassTypesAssignable should prevent us from getting here if the types
// are referentially equal.
assert (lhsWildcard != rhsWildcard);
assert (lhsWildcard != null && rhsWildcard != null);
if (lhsWildcard.getLowerBounds().length > 0 && rhsWildcard.getLowerBounds().length > 0) {
// lhsType: ? super T, rhsType ? super U
return areClassTypesAssignable(rhsWildcard.getFirstBound(), lhsWildcard.getFirstBound());
} else if (lhsWildcard.getUpperBounds().length > 0
&& lhsWildcard.getLowerBounds().length == 0
&& rhsWildcard.getUpperBounds().length > 0
&& rhsWildcard.getLowerBounds().length == 0) {
// lhsType: ? extends T, rhsType: ? extends U
return areClassTypesAssignable(lhsWildcard.getFirstBound(), rhsWildcard.getFirstBound());
}
return false;
}
/**
* Returns <code>true</code> if the lhs and rhs are assignable without consideration of the
* supertypes of the rhs.
*
* @param lhsType
* @param rhsType
* @return true if rhsType can be assigned to lhsType
*/
private static boolean areClassTypesAssignableNoSupers(JClassType lhsType, JClassType rhsType) {
if (lhsType == rhsType) {
// Done, these are the same types.
return true;
}
if (lhsType == lhsType.getOracle().getJavaLangObject()) {
// Done, any type can be assigned to object.
return true;
}
/*
* Get the generic base type, if there is one, for the lhs type and convert
* it to a raw type if it is generic.
*/
if (lhsType.isGenericType() != null) {
lhsType = lhsType.isGenericType().getRawType();
}
if (rhsType.isGenericType() != null) {
// Treat the generic rhs type as a raw type.
rhsType = rhsType.isGenericType().getRawType();
}
// Check for JTypeParameters.
JTypeParameter lhsTypeParam = lhsType.isTypeParameter();
JTypeParameter rhsTypeParam = rhsType.isTypeParameter();
if (lhsTypeParam != null) {
JClassType[] lhsTypeBounds = lhsTypeParam.getBounds();
for (JClassType lhsTypeBound : lhsTypeBounds) {
if (!areClassTypesAssignable(lhsTypeBound, rhsType)) {
// Done, the rhsType was not assignable to one of the bounds.
return false;
}
}
// Done, the rhsType was assignable to all of the bounds.
return true;
} else if (rhsTypeParam != null) {
JClassType[] possibleSubtypeBounds = rhsTypeParam.getBounds();
for (JClassType possibleSubtypeBound : possibleSubtypeBounds) {
if (areClassTypesAssignable(lhsType, possibleSubtypeBound)) {
// Done, at least one bound is assignable to this type.
return true;
}
}
return false;
}
/*
* Check for JWildcards. We have not examined this part in great detail
* since there should not be top level wildcard types.
*/
JWildcardType lhsWildcard = lhsType.isWildcard();
JWildcardType rhsWildcard = rhsType.isWildcard();
if (lhsWildcard != null && rhsWildcard != null) {
// Both types are wildcards.
return areWildcardsAssignable(lhsWildcard, rhsWildcard);
} else if (lhsWildcard != null) {
// The lhs type is a wildcard but the rhs is not.
// ? extends T, U OR ? super T, U
JClassType[] lowerBounds = lhsWildcard.getLowerBounds();
if (lowerBounds.length > 0) {
// ? super T will reach object no matter what the rhs type is
return true;
} else {
return areClassTypesAssignable(lhsWildcard.getFirstBound(), rhsType);
}
}
// Check for JArrayTypes.
JArrayType lhsArray = lhsType.isArray();
JArrayType rhsArray = rhsType.isArray();
if (lhsArray != null) {
if (rhsArray == null) {
return false;
} else {
return areArraysAssignable(lhsArray, rhsArray);
}
} else if (rhsArray != null) {
// Safe although perhaps not necessary
return false;
}
// Check for JParameterizedTypes and JRawTypes.
JMaybeParameterizedType lhsMaybeParameterized = lhsType.isMaybeParameterizedType();
JMaybeParameterizedType rhsMaybeParameterized = rhsType.isMaybeParameterizedType();
if (lhsMaybeParameterized != null && rhsMaybeParameterized != null) {
if (lhsMaybeParameterized.getBaseType() == rhsMaybeParameterized.getBaseType()) {
if (lhsMaybeParameterized.isRawType() != null
|| rhsMaybeParameterized.isRawType() != null) {
/*
* Any raw type can be assigned to or from any parameterization of its
* generic type.
*/
return true;
}
assert (lhsMaybeParameterized.isRawType() == null
&& rhsMaybeParameterized.isRawType() == null);
JParameterizedType lhsParameterized = lhsMaybeParameterized.isParameterized();
JParameterizedType rhsParameterized = rhsMaybeParameterized.isParameterized();
assert (lhsParameterized != null && rhsParameterized != null);
return areTypeArgumentsAssignable(lhsParameterized, rhsParameterized);
}
}
// Default to not being assignable.
return false;
}