Package io.permazen.kv.raft.fallback

Interface MergeStrategy

All Known Implementing Classes:

NullMergeStrategy, OverwriteMergeStrategy

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface MergeStrategy

Merge strategy used by a FallbackKVDatabase when migrating from one underlying database to another.

Method Summary

Modifier and Type	Method	Description
void	mergeAndCommit(KVTransaction src, KVTransaction dst, Date lastActiveTime)	Merge data from the source database being migrated away from into the destination database being migrated to.

Method Details

mergeAndCommit

void mergeAndCommit(KVTransaction src,
 KVTransaction dst,
 Date lastActiveTime)

Merge data from the source database being migrated away from into the destination database being migrated to.

This method should commit() both transactions before returning; src should be committed before dst.

If an exception is thrown, rollback() will be invoked on both transactions (a rollback() on an already-commit()'ed transaction does nothing).

Parameters:

src - read-only view into the database being migrated away from

dst - read-write transaction open on the database being migrated to

lastActiveTime - time that dst was last active, or null if never

Throws:

RuntimeException - if the merge or either commit() fails