Why TraverserContext variables use Class<?> as key?

[qzchenwl]

Why TraverserContext variables use Class<?> as key, why not just use String?

graphql-java/src/main/java/graphql/util/TraverserContext.java

Lines 127 to 136 in 0e6921e

	/**
	* Obtains a context local variable
	*
	* @param <S> type of the variable
	* @param key key to lookup the variable value
	*
	* @return a variable value or {@code null}
	*/
	<S> S getVar(Class<? super S> key);

What if I have more than one variables of the same type?

Why SchemaTraverser is setting root var with different type(SchemaTraverser.class vs Map<String, GraphQLNamedType>) ?

graphql-java/src/main/java/graphql/schema/SchemaTraverser.java

Lines 41 to 44 in 0e6921e

	public TraverserResult depthFirst(final GraphQLTypeVisitor graphQLTypeVisitor,
	Collection<? extends GraphQLSchemaElement> roots,
	Map<String, GraphQLNamedType> types) {
	Traverser<GraphQLSchemaElement> traverser = initTraverser().rootVar(SchemaTraverser.class, types);

[bbakerman]

This was just to keep the API a little tighter. Yes strings are excellent keys but they are also poor keys in the sense of knowing that a CodeRegistry is available as a var say.

So we chose class instead

What if I have more than one variables of the same type?

So create a class and put those many things into that class

class ContainerOfThings {
   List<String,Object> things
}

You will know its your ContainerOfThings class!