ClassRegistry (Apache TinkerPop 3.8.2 API)

java.lang.Object
- org.apache.tinkerpop.gremlin.structure.io.ClassRegistry

```
public final class ClassRegistry
extends Object
```
Holds the classes a GraphBinary, GraphSON or Gryo Class value may name, so such a name is resolved from this registry rather than by a class loader. Registration is a Java API only and refuses a TraversalStrategy, which belongs to TraversalStrategies.GlobalCache.
lookup(String) also falls back to GlobalCache.getRegisteredStrategyClassByFullName, so a strategy the selector can construct is nameable without being registered here.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static Optional<Class<?>>`	`lookup(String className)`	Looks up a class nameable as a generic `Class` value, without loading it.
`static void`	`register(Class<?> clazz)`	Registers a class as nameable as a generic `Class` value, without making it constructible from a serialized traversal, so it cannot widen what the selector can construct.
`static void`	`unregister(Class<?> clazz)`	Removes a class from this registry, so it is no longer nameable as a generic `Class` value.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - register
```
public static void register(Class<?> clazz)
```
    Registers a class as nameable as a generic Class value, without making it constructible from a serialized traversal, so it cannot widen what the selector can construct. A TraversalStrategy is refused with an IllegalArgumentException and a null with a NullPointerException.
  - unregister
```
public static void unregister(Class<?> clazz)
```
    Removes a class from this registry, so it is no longer nameable as a generic Class value. A TraversalStrategy is refused because strategies belong to TraversalStrategies.GlobalCache, and a null is refused with a NullPointerException.
  - lookup
```
public static Optional<Class<?>> lookup(String className)
```
    Looks up a class nameable as a generic Class value, without loading it. Matching is on the exact Class.getName(), never assignability, so registering a superclass or an interface does not admit its subtypes. A null name yields an empty Optional, since a Class value can name nothing.