Package org.infinispan.functional

Interface MetaParam.Lookup

All Known Subinterfaces:
EntryView.ReadEntryView<K,V>, EntryView.ReadWriteEntryView<K,V>, EntryViews.AccessLoggingReadWriteView<K,V>
All Known Implementing Classes:
MetaParamsInternalMetadata
Enclosing interface:
MetaParam<T>
@Experimental public static interface MetaParam.Lookup
Provides metadata parameter lookup capabilities using Class as lookup key.

When the MetaParam type is generic, e.g. MetaParam.MetaEntryVersion, passing the correct Class information so that the return of findMetaParam(java.lang.Class<T>) is of the expected type can be a bit tricky.

invalid reference 
MetaEntryVersion#type()
offers an easy way to retrieve the expected MetaParam type from findMetaParam(java.lang.Class<T>) at the expense of some type safety: 

     Class<MetaEntryVersion<Long>> type = MetaEntryVersion.type();
     Optional<MetaEntryVersion<Long>> metaVersion =
          metaParamLookup.findMetaParam(type);
In the future, the API might be adjusted to provide additional lookup methods where this situation is improved. Also, if the MetaParam type is not generic, e.g. MetaParam.MetaLifespan, the problem is avoided altogether: 

     Optional<MetaLifespan<Long>> metaLifespan =
          metaParamLookup.findMetaParam(MetaLifespan.class);

A user that queries meta parameters can never assume that the meta parameter will always exist because some of them depends on the cache usage.

Since:
8.0

  • Method Summary

    Modifier and Type
    Method
    Description
    <T extends MetaParam>
    Optional<T>
    findMetaParam(Class<T> type)
    Returns a non-empty Optional instance containing a metadata parameter instance that can be assigned to the type Class passed in, or an empty Optional if no metadata can be assigned to that type.

  • Method Details

    • findMetaParam

      <T extends MetaParam> Optional<T> findMetaParam(Class<T> type)
      Returns a non-empty Optional instance containing a metadata parameter instance that can be assigned to the type Class passed in, or an empty Optional if no metadata can be assigned to that type.
      Type Parameters:
      T - metadata parameter type