ru.vyarus.java.generics.resolver.util.walk

Class TypesWalker

java.lang.Object

ru.vyarus.java.generics.resolver.util.walk.TypesWalker

public final class TypesWalker
extends java.lang.Object

Deep types analysis utility.

Algorithm:

• If types are not compatible - notify fail
• Ask visitor to continue
• If one if types is Object - stop
• Look if types are arrays and cycle with actual array type
• If types contains generics (T<A,B>) then align types (resolve hierarchy for upper type and compare generics of lower types) and cycle for each generic pair

Generics rules are not honored. For example, List<?> is considered as List<Object> and assumed compatible with any list. <? extends Something> is considered as Something and compatible with any subtype.

The only exception is wildcard's lower bound: <? super Something> is compatible with any super type of Something but not compatible with any subtype.

If generic declares multiple bounds T extends A & B and it was not resolved with actual type (sub type did not declare exact generic for it), then both bounds will be used for comparison.

When one of types is primitive then wrapper class used instead (e.g. Integer instead of int) to simplify visitor logic.

Since:

11.05.2018

Method Summary

Modifier and Type	Method and Description
static void	walk(java.lang.reflect.Type one, java.lang.reflect.Type two, TypesVisitor visitor) Walk will stop if visitor tells it's enough or when hierarchy incompatibility will be found.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

walk

public static void walk(java.lang.reflect.Type one,
                        java.lang.reflect.Type two,
                        TypesVisitor visitor)

Walk will stop if visitor tells it's enough or when hierarchy incompatibility will be found.

Parameters:

one - first type

two - second type

visitor - visitor