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/*
* Copyright 2006 Amazon Technologies, Inc. or its affiliates.
* Amazon, Amazon.com and Carbonado are trademarks or registered trademarks
* of Amazon Technologies, Inc. or its affiliates. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.amazon.carbonado.spi;
import com.amazon.carbonado.Repository;
import com.amazon.carbonado.Transaction;
import com.amazon.carbonado.Storable;
import com.amazon.carbonado.PersistException;
/**
* Neatly scope a transactional operation. To use, a subclass of RunnableTransaction should be
* provided which implements any one of the three flavors of the body method.
* The default implementations pass control from most specific to least specific -- that is,
* from {@link #body(Storable)} to {@link #body()} -- so the
* implementor is free to override whichever makes the most sense.
*
* <P>A typical use pattern would be:
*
* <pre>
* RunnableTransaction rt = new RunnableTransaction(repository) {
* public void body() throws PersistException {
* for (Storable s : someFieldContainingStorables) {
* s.insert();
* }
* };
* rt.run();
* </pre>
*
* @author Don Schneider
* @author Todd V. Jonker (jonker)
*/
public class RunnableTransaction {
final Repository mRepo;
public RunnableTransaction(Repository repo) {
mRepo = repo;
}
/**
* Enter a transaction, execute {@link #body(Storable)} for each storable, commit
* if no exception, and exit the transaction.
* @param storables array of storables on which to operate
* @throws PersistException
*/
public final <S extends Storable> void run(S storable, S... storables)
throws PersistException
{
Transaction txn = mRepo.enterTransaction();
try {
for (S s : storables) {
body(s);
}
txn.commit();
} finally {
txn.exit();
}
}
/**
* Enter a transaction, execute {@link #body(Storable)} on the provided storable, commit if no
* exception, and exit the transaction.
* @param storable on which to operate
* @throws PersistException
*/
public final <S extends Storable> void run(S storable) throws PersistException {
Transaction txn = mRepo.enterTransaction();
try {
body(storable);
txn.commit();
} finally {
txn.exit();
}
}
/**
* Enter a transaction on the provided repository, execute {@link #body()}
* @throws PersistException
*/
public final void run() throws PersistException {
Transaction txn = mRepo.enterTransaction();
try {
body();
txn.commit();
} finally {
txn.exit();
}
}
public <S extends Storable> void body(S s) throws PersistException {
body();
}
public void body() throws PersistException {
}
public String toString() {
return "RunnableTransaction(" + mRepo + ')';
}
}
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