refactor(common): move AbstractDistributedTransactionProvider from api to common

AbstractDistributedTransactionProvider is an internal abstract helper base, not part of the public
API; its sibling abstract bases (AbstractDistributedTransaction, AbstractDistributedTransactionManager,
AbstractTwoPhaseCommitTransaction, ...) already live in com.scalar.db.common, so it belongs there
too. The public SPI contract, the DistributedTransactionProvider interface, stays in com.scalar.db.api.

The in-tree subclasses (ConsensusCommitProvider, JdbcTransactionProvider) are updated to the new
import. Out-of-tree subclasses that extend this base (e.g. the cluster's transaction providers) must
update their import to com.scalar.db.common.AbstractDistributedTransactionProvider in a paired change.

Author: brfrn169

…tractDistributedTransactionProvider.java …tractDistributedTransactionProvider.javacore/src/main/java/com/scalar/db/api/AbstractDistributedTransactionProvider.java renamed to core/src/main/java/com/scalar/db/common/AbstractDistributedTransactionProvider.java core/src/main/java/com/scalar/db/api/AbstractDistributedTransactionProvider.java renamed to core/src/main/java/com/scalar/db/common/AbstractDistributedTransactionProvider.java

@@ -1,10 +1,8 @@
-package com.scalar.db.api;
+package com.scalar.db.common;
 
-import com.scalar.db.common.ActiveTransactionManagedDistributedTransactionManager;
-import com.scalar.db.common.ActiveTransactionManagedTwoPhaseCommitTransactionManager;
-import com.scalar.db.common.AttributePropagatingDistributedTransactionManager;
-import com.scalar.db.common.StateManagedDistributedTransactionManager;
-import com.scalar.db.common.StateManagedTwoPhaseCommitTransactionManager;
+import com.scalar.db.api.DistributedTransactionManager;
+import com.scalar.db.api.DistributedTransactionProvider;
+import com.scalar.db.api.TwoPhaseCommitTransactionManager;
 import com.scalar.db.config.DatabaseConfig;
 import javax.annotation.Nullable;
 

core/src/main/java/com/scalar/db/transaction/consensuscommit/ConsensusCommitProvider.java

@@ -1,10 +1,10 @@
 package com.scalar.db.transaction.consensuscommit;
 
-import com.scalar.db.api.AbstractDistributedTransactionProvider;
 import com.scalar.db.api.DistributedTransactionAdmin;
 import com.scalar.db.api.DistributedTransactionManager;
 import com.scalar.db.api.TwoPhaseCommit;
 import com.scalar.db.api.TwoPhaseCommitTransactionManager;
+import com.scalar.db.common.AbstractDistributedTransactionProvider;
 import com.scalar.db.config.DatabaseConfig;
 
 public class ConsensusCommitProvider extends AbstractDistributedTransactionProvider {

core/src/main/java/com/scalar/db/transaction/jdbc/JdbcTransactionProvider.java

@@ -1,10 +1,10 @@
 package com.scalar.db.transaction.jdbc;
 
-import com.scalar.db.api.AbstractDistributedTransactionProvider;
 import com.scalar.db.api.DistributedTransactionAdmin;
 import com.scalar.db.api.DistributedTransactionManager;
 import com.scalar.db.api.TwoPhaseCommit;
 import com.scalar.db.api.TwoPhaseCommitTransactionManager;
+import com.scalar.db.common.AbstractDistributedTransactionProvider;
 import com.scalar.db.config.DatabaseConfig;
 import com.scalar.db.storage.jdbc.JdbcConfig;
 import javax.annotation.Nullable;