Trait frame_support::traits::tokens::nonfungibles::Inspect

pub trait Inspect<AccountId> {
    type InstanceId;
    type ClassId;
    fn owner(
        class: &Self::ClassId, 
        instance: &Self::InstanceId
    ) -> Option<AccountId>;

    fn class_owner(_class: &Self::ClassId) -> Option<AccountId> { ... }
    fn attribute(
        _class: &Self::ClassId, 
        _instance: &Self::InstanceId, 
        _key: &[u8]
    ) -> Option<Vec<u8>> { ... }
    fn typed_attribute<K: Encode, V: Decode>(
        class: &Self::ClassId, 
        instance: &Self::InstanceId, 
        key: &K
    ) -> Option<V> { ... }
    fn class_attribute(_class: &Self::ClassId, _key: &[u8]) -> Option<Vec<u8>> { ... }
    fn typed_class_attribute<K: Encode, V: Decode>(
        class: &Self::ClassId, 
        key: &K
    ) -> Option<V> { ... }
    fn can_transfer(
        _class: &Self::ClassId, 
        _instance: &Self::InstanceId
    ) -> bool { ... }
}

Trait for providing an interface to many read-only NFT-like sets of asset instances.

Associated Types

type InstanceId

Type for identifying an asset instance.

type ClassId

Type for identifying an asset class (an identifier for an independent collection of asset instances).

Required methods

fn owner(
    class: &Self::ClassId,
    instance: &Self::InstanceId
) -> Option<AccountId>

Returns the owner of asset instance of class, or None if the asset doesn’t exist (or somehow has no owner).

Provided methods

fn class_owner(_class: &Self::ClassId) -> Option<AccountId>

Returns the owner of the asset class, if there is one. For many NFTs this may not make any sense, so users of this API should not be surprised to find an asset class results in None here.

fn attribute(
    _class: &Self::ClassId,
    _instance: &Self::InstanceId,
    _key: &[u8]
) -> Option<Vec<u8>>

Returns the attribute value of instance of class corresponding to key.

By default this is None; no attributes are defined.

fn typed_attribute<K: Encode, V: Decode>(
    class: &Self::ClassId,
    instance: &Self::InstanceId,
    key: &K
) -> Option<V>

Returns the strongly-typed attribute value of instance of class corresponding to key.

By default this just attempts to use attribute.

fn class_attribute(_class: &Self::ClassId, _key: &[u8]) -> Option<Vec<u8>>

Returns the attribute value of class corresponding to key.

By default this is None; no attributes are defined.

fn typed_class_attribute<K: Encode, V: Decode>(
    class: &Self::ClassId,
    key: &K
) -> Option<V>

Returns the strongly-typed attribute value of class corresponding to key.

By default this just attempts to use class_attribute.

fn can_transfer(_class: &Self::ClassId, _instance: &Self::InstanceId) -> bool

Returns true if the asset instance of class may be transferred.

Default implementation is that all assets are transferable.

Implementors