@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
return typeVariable.equals(((TypeVarBoundedType) o).typeVariable);
}
/** Returns a new {@code TypeResolver} with {@code variable} mapping to {@code type}. */
final TypeTable where(Map<? extends TypeVariable<?>, ? extends Type> mappings) {
ImmutableMap.Builder<TypeVariable<?>, Type> builder = ImmutableMap.builder();
builder.putAll(map);
for (Map.Entry<? extends TypeVariable<?>, ? extends Type> mapping : mappings.entrySet()) {
TypeVariable<?> variable = mapping.getKey();
Type type = mapping.getValue();
checkArgument(!variable.equals(type), "Type variable %s bound to itself", variable);
builder.put(variable, type);
}
return new TypeTable(builder.build());
}
private static boolean isAssignable(
Type paramType, TypeVariable paramTypeVariable, Map paramMap) {
if (paramType == null) return true;
if (paramTypeVariable == null) return false;
if (paramTypeVariable.equals(paramType)) return true;
if ((paramType instanceof TypeVariable)) {
Type[] arrayOfType = getImplicitBounds((TypeVariable) paramType);
int i = arrayOfType.length;
for (int j = 0; j < i; j++)
if (isAssignable(arrayOfType[j], paramTypeVariable, paramMap)) return true;
}
if (((paramType instanceof Class))
|| ((paramType instanceof ParameterizedType))
|| ((paramType instanceof GenericArrayType))
|| ((paramType instanceof WildcardType))) return false;
throw new IllegalStateException("found an unhandled type: " + paramType);
}
/**
* Checks if the subject type may be implicitly cast to the target type variable following the
* Java generics rules.
*
* @param type the subject type to be assigned to the target type
* @param toTypeVariable the target type variable
* @return true if <code>type</code> is assignable to <code>toTypeVariable</code>.
*/
private static boolean isAssignable(
Type type, TypeVariable<?> toTypeVariable, Map<TypeVariable<?>, Type> typeVarAssigns) {
if (type == null) {
return true;
}
// only a null type can be assigned to null type which
// would have cause the previous to return true
if (toTypeVariable == null) {
return false;
}
// all types are assignable to themselves
if (toTypeVariable.equals(type)) {
return true;
}
if (type instanceof TypeVariable<?>) {
// a type variable is assignable to another type variable, if
// and only if the former is the latter, extends the latter, or
// is otherwise a descendant of the latter.
Type[] bounds = getImplicitBounds((TypeVariable<?>) type);
for (Type bound : bounds) {
if (isAssignable(bound, toTypeVariable, typeVarAssigns)) {
return true;
}
}
}
if (type instanceof Class<?>
|| type instanceof ParameterizedType
|| type instanceof GenericArrayType
|| type instanceof WildcardType) {
return false;
}
throw new IllegalStateException("found an unhandled type: " + type);
}
private void map(final TypeVariable<?> var, final Type arg) {
if (mappings.containsKey(var)) {
// Mapping already established
// This is possible when following both superClass -> enclosingClass
// and enclosingclass -> superClass paths.
// Since we follow the path of superclass first, enclosing second,
// superclass mapping should take precedence.
return;
}
// First, check whether var -> arg forms a cycle
for (Type t = arg; t != null; t = mappings.get(t)) {
if (var.equals(t)) {
// cycle detected, remove the entire cycle from the mapping so that
// each type variable resolves deterministically to itself.
// Otherwise, a F -> T cycle will end up resolving both F and T
// nondeterministically to either F or T.
for (Type x = arg; x != null; x = mappings.remove(x)) {}
return;
}
}
mappings.put(var, arg);
}
