Java tutorial
/* * 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 org.jdbi.v3.spring4; import java.util.HashSet; import java.util.Set; import org.jdbi.v3.core.Jdbi; import org.jdbi.v3.core.Handle; import org.springframework.transaction.support.TransactionSynchronizationAdapter; import org.springframework.transaction.support.TransactionSynchronizationManager; /** * Utility for working with Jdbi and Spring transaction bound resources */ public class JdbiUtil { private static final Set<Handle> TRANSACTIONAL_HANDLES = new HashSet<>(); private JdbiUtil() { throw new UnsupportedOperationException("utility class"); } /** * Obtain a Handle instance, either the transactionally bound one if we are in a transaction, * or a new one otherwise. * @param jdbi the Jdbi instance from which to obtain the handle * * @return the Handle instance */ public static Handle getHandle(Jdbi jdbi) { Handle bound = (Handle) TransactionSynchronizationManager.getResource(jdbi); if (bound == null) { bound = jdbi.open(); if (TransactionSynchronizationManager.isSynchronizationActive()) { TransactionSynchronizationManager.bindResource(jdbi, bound); TransactionSynchronizationManager.registerSynchronization(new Adapter(jdbi, bound)); TRANSACTIONAL_HANDLES.add(bound); } } return bound; } /** * Close a handle if it is not transactionally bound, otherwise no-op * @param handle the handle to consider closing */ public static void closeIfNeeded(Handle handle) { if (!TRANSACTIONAL_HANDLES.contains(handle)) { handle.close(); } } private static class Adapter extends TransactionSynchronizationAdapter { private final Jdbi db; private final Handle handle; Adapter(Jdbi db, Handle handle) { this.db = db; this.handle = handle; } @Override public void resume() { TransactionSynchronizationManager.bindResource(db, handle); } @Override public void suspend() { TransactionSynchronizationManager.unbindResource(db); } @Override public void beforeCompletion() { TRANSACTIONAL_HANDLES.remove(handle); TransactionSynchronizationManager.unbindResource(db); } } }