Java tutorial
/** * Copyright 2009 The Apache Software Foundation 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.hadoop.hbase.client.transactional; import java.io.IOException; import java.util.HashMap; import java.util.Map; import javax.transaction.xa.XAException; import javax.transaction.xa.XAResource; import javax.transaction.xa.Xid; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; /** * View hbase as a JTA transactional resource. This allows it to participate in transactions across multiple resources. */ public class JtaXAResource implements XAResource { static final Log LOG = LogFactory.getLog(JtaXAResource.class); private Map<Xid, TransactionState> xidToTransactionState = new HashMap<Xid, TransactionState>(); private final TransactionManager transactionManager; private ThreadLocal<TransactionState> threadLocalTransactionState = new ThreadLocal<TransactionState>(); public JtaXAResource(final TransactionManager transactionManager) { this.transactionManager = transactionManager; } public void commit(final Xid xid, final boolean onePhase) throws XAException { LOG.trace("commit [" + xid.toString() + "] " + (onePhase ? "one phase" : "two phase")); TransactionState state = xidToTransactionState.remove(xid); if (state == null) { throw new XAException(XAException.XAER_NOTA); } try { if (onePhase) { transactionManager.tryCommit(state); } else { transactionManager.doCommit(state); } } catch (CommitUnsuccessfulException e) { throw new XAException(XAException.XA_RBROLLBACK); } catch (UnsuccessfulDDLException e) { throw new XAException(XAException.XA_RBROLLBACK); } catch (IOException e) { XAException xae = new XAException(XAException.XAER_RMERR); xae.initCause(e); throw xae; } finally { threadLocalTransactionState.remove(); } } public void end(final Xid xid, final int flags) throws XAException { LOG.trace("end [" + xid.toString() + "] "); threadLocalTransactionState.remove(); } public void forget(final Xid xid) throws XAException { LOG.trace("forget [" + xid.toString() + "] "); threadLocalTransactionState.remove(); TransactionState state = xidToTransactionState.remove(xid); if (state != null) { try { transactionManager.abort(state); } catch (Exception e) { XAException xae = new XAException(XAException.XAER_RMERR); xae.initCause(e); throw xae; } } } public int getTransactionTimeout() throws XAException { return 0; } public boolean isSameRM(final XAResource xares) throws XAException { if (xares instanceof JtaXAResource) { return true; } return false; } public int prepare(final Xid xid) throws XAException { LOG.trace("prepare [" + xid.toString() + "] "); TransactionState state = xidToTransactionState.get(xid); int status; try { status = this.transactionManager.prepareCommit(state); } catch (CommitUnsuccessfulException e) { XAException xae = new XAException(XAException.XA_HEURRB); xae.initCause(e); throw xae; } catch (IOException e) { XAException xae = new XAException(XAException.XAER_RMERR); xae.initCause(e); throw xae; } switch (status) { case TransactionalReturn.COMMIT_OK: return XAResource.XA_OK; case TransactionalReturn.COMMIT_OK_READ_ONLY: return XAResource.XA_RDONLY; default: throw new XAException(XAException.XA_RBPROTO); } } public Xid[] recover(final int flag) throws XAException { return xidToTransactionState.keySet().toArray(new Xid[] {}); } public void rollback(final Xid xid) throws XAException { LOG.trace("rollback [" + xid.toString() + "] "); forget(xid); threadLocalTransactionState.remove(); } public boolean setTransactionTimeout(final int seconds) throws XAException { return false; // Currently not supported. (Only global lease time) } public void start(final Xid xid, final int flags) throws XAException { LOG.trace("start [" + xid.toString() + "] "); // TODO, check flags TransactionState state = this.transactionManager.beginTransaction(); threadLocalTransactionState.set(state); xidToTransactionState.put(xid, state); } /** * @return the threadLocalTransaction state. */ public TransactionState getThreadLocalTransactionState() { return threadLocalTransactionState.get(); } }