/*
    * Copyright 2006-2007 the original author or authors.
    *
    * 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.springframework.batch.support.transaction;
  
  import java.util.Stack;
  
  import org.springframework.transaction.TransactionDefinition;
  import org.springframework.transaction.TransactionException;
  import org.springframework.transaction.support.AbstractPlatformTransactionManager;
  import org.springframework.transaction.support.DefaultTransactionStatus;
  import org.springframework.transaction.support.TransactionSynchronizationManager;
  
  public class ResourcelessTransactionManager extends AbstractPlatformTransactionManager {
  
      @Override
  	protected void doBegin(Object transaction, TransactionDefinition definition) throws TransactionException {
  		((ResourcelessTransaction) transaction).begin();
  	}
  
      @Override
  	protected void doCommit(DefaultTransactionStatus status) throws TransactionException {
  		logger.debug("Committing resourceless transaction on [" + status.getTransaction() + "]");
  	}
  
      @Override
  	protected Object doGetTransaction() throws TransactionException {
  		Object transaction = new ResourcelessTransaction();
  		Stack<Object> resources;
  		if (!TransactionSynchronizationManager.hasResource(this)) {
  			resources = new Stack<Object>();
  			TransactionSynchronizationManager.bindResource(this, resources);
  		}
  		else {
  			@SuppressWarnings("unchecked")
  			Stack<Object> stack = (Stack<Object>) TransactionSynchronizationManager.getResource(this);
  			resources = stack;
  		}
  		resources.push(transaction);
  		return transaction;
  	}
  
      @Override
  	protected void doRollback(DefaultTransactionStatus status) throws TransactionException {
  		logger.debug("Rolling back resourceless transaction on [" + status.getTransaction() + "]");
  	}
  
      @Override
  	protected boolean isExistingTransaction(Object transaction) throws TransactionException {
  		if (TransactionSynchronizationManager.hasResource(this)) {
  			@SuppressWarnings("unchecked")
  			Stack<Object> stack = (Stack<Object>) TransactionSynchronizationManager.getResource(this);
  			return stack.size() > 1;
  		}
  		return ((ResourcelessTransaction) transaction).isActive();
  	}
  
      @Override
  	protected void doSetRollbackOnly(DefaultTransactionStatus status) throws TransactionException {
  	}
  
      @Override
  	protected void doCleanupAfterCompletion(Object transaction) {
  		@SuppressWarnings("unchecked")
  		Stack<Object> list = (Stack<Object>) TransactionSynchronizationManager.getResource(this);
  		Stack<Object> resources = list;
  		resources.clear();
  		TransactionSynchronizationManager.unbindResource(this);
  		((ResourcelessTransaction) transaction).clear();
  	}
  
  	private static class ResourcelessTransaction {
  
  		private boolean active = false;
  
  		public boolean isActive() {
  			return active;
  		}
  
  		public void begin() {
  			active = true;
  		}
  
  		public void clear() {
  			active = false;
  		}
 
 	}
 
 }