| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more contributor license |
| * agreements. See the NOTICE file distributed with this work for additional information regarding |
| * copyright ownership. The ASF licenses this file to You 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 org.apache.geode.cache; |
| |
| |
| /** |
| * A callback that is allowed to veto a transaction. Only one TransactionWriter can exist per cache, |
| * and only one TransactionWriter will be fired in the entire distributed system for each |
| * transaction. |
| * |
| * <p> |
| * This writer can be used to update a backend data source before the GemFire cache is updated |
| * during commit. If the backend update fails, the implementer can throw a |
| * {@link TransactionWriterException} to veto the transaction. |
| * |
| * <p> |
| * WARNING: To avoid risk of deadlock, do not invoke CacheFactory.getAnyInstance() from within any |
| * callback methods. Instead use TransactionEvent.getCache(). |
| * |
| * @see CacheTransactionManager#setWriter |
| * @since GemFire 6.5 |
| */ |
| |
| public interface TransactionWriter extends CacheCallback { |
| |
| /** |
| * Called before the transaction has finished committing, but after conflict checking. Provides an |
| * opportunity for implementors to cause transaction abort by throwing a |
| * TransactionWriterException |
| * |
| * @param event the TransactionEvent |
| * @see CacheTransactionManager#commit |
| * @throws TransactionWriterException in the event that the transaction should be rolled back |
| */ |
| void beforeCommit(TransactionEvent event) throws TransactionWriterException; |
| |
| } |
