private static boolean isAssignable()

in src/main/java/org/apache/commons/lang3/reflect/TypeUtils.java [1352:1427]
49 lines of code
15 McCabe index (conditional complexity)

    private static boolean isAssignable(final Type type, final WildcardType toWildcardType,
            final 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 (toWildcardType == null) {
            return false;
        }

        // all types are assignable to themselves
        if (toWildcardType.equals(type)) {
            return true;
        }

        final Type[] toUpperBounds = getImplicitUpperBounds(toWildcardType);
        final Type[] toLowerBounds = getImplicitLowerBounds(toWildcardType);

        if (type instanceof WildcardType) {
            final WildcardType wildcardType = (WildcardType) type;
            final Type[] upperBounds = getImplicitUpperBounds(wildcardType);
            final Type[] lowerBounds = getImplicitLowerBounds(wildcardType);

            for (Type toBound : toUpperBounds) {
                // if there are assignments for unresolved type variables,
                // now's the time to substitute them.
                toBound = substituteTypeVariables(toBound, typeVarAssigns);

                // each upper bound of the subject type has to be assignable to
                // each
                // upper bound of the target type
                for (final Type bound : upperBounds) {
                    if (!isAssignable(bound, toBound, typeVarAssigns)) {
                        return false;
                    }
                }
            }

            for (Type toBound : toLowerBounds) {
                // if there are assignments for unresolved type variables,
                // now's the time to substitute them.
                toBound = substituteTypeVariables(toBound, typeVarAssigns);

                // each lower bound of the target type has to be assignable to
                // each
                // lower bound of the subject type
                for (final Type bound : lowerBounds) {
                    if (!isAssignable(toBound, bound, typeVarAssigns)) {
                        return false;
                    }
                }
            }
            return true;
        }

        for (final Type toBound : toUpperBounds) {
            // if there are assignments for unresolved type variables,
            // now's the time to substitute them.
            if (!isAssignable(type, substituteTypeVariables(toBound, typeVarAssigns),
                    typeVarAssigns)) {
                return false;
            }
        }

        for (final Type toBound : toLowerBounds) {
            // if there are assignments for unresolved type variables,
            // now's the time to substitute them.
            if (!isAssignable(substituteTypeVariables(toBound, typeVarAssigns), type,
                    typeVarAssigns)) {
                return false;
            }
        }
        return true;
    }