Ben Chambers created BEAM-247: --------------------------------- Summary: CombineFn's only definable/usable inside sdk.transforms package Key: BEAM-247 URL: https://issues.apache.org/jira/browse/BEAM-247 Project: Beam Issue Type: Bug Components: sdk-java-core Reporter: Ben Chambers Assignee: Pei He Priority: Critical
{code:java} public abstract static class CombineFn<InputT, AccumT, OutputT> extends AbstractGlobalCombineFn<InputT, AccumT, OutputT> { /* ... */ } abstract static class AbstractGlobalCombineFn<InputT, AccumT, OutputT> implements GlobalCombineFn<InputT, AccumT, OutputT>, Serializable { /* ... */ } {code} Since {{AbstractGlobalCombineFn}} is package protected (and therefore not visible outside of the {{transform}} package, it is not possible to cast any class that extends {{CombineFn}} to a {{GlobalCombineFn}} outside of this package. This prevents applying existing {{CombineFn}}s directly (such as {{Combine.perKey(new Sum.SumIntegersFn())}}, as used in our documentation) and also means that a user cannot define their own {{CombineFn}} unless they put them in the {{transform}} package. -- This message was sent by Atlassian JIRA (v6.3.4#6332)