Spring, Springmodules, JBPM持久化集成--优雅的背后(Part1)

Spring, Springmodules, JBPM持久化集成理解系列二?

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【本系列如需转载，请注明作者及出处】?

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本系列文章假设阅者具备以下知识：
1，ThreadLocal相关知识
2，Spring持久化，事务管理相关知识
3，Hibernate 持久化相关知识
4，Jbpm 持久化相关知识
5，Springmodules项目相关知识
6，相关J2EE知识

且具备以下材料：
1，Spring源代码
2，Hibernate源代码
3，Jbpm源代码
4，Springmodules源代码?

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? 本篇尝试探讨SpringModules集成的背后逻辑，这涉及到JbpmContext持久化的哲学。?

public TaskInstance loadTaskInstance(long taskInstanceId) { return getTaskMgmtSession().loadTaskInstance(taskInstanceId);}public TaskMgmtSession getTaskMgmtSession() { PersistenceService persistenceService = getPersistenceService(); if (persistenceService==null) return null; return (persistenceService!=null ? persistenceService.getTaskMgmtSession() : null);

public TaskMgmtSession getTaskMgmtSession() { if (taskMgmtSession==null) { Session session = getSession(); if (session!=null) { taskMgmtSession = new TaskMgmtSession(session); } } return taskMgmtSession; }

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好了，到此我们就差不多达到Jbpm管理Session的环节了，我们再进入到getSession方法，看看它到底做了什么事情：

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准备工作：1）以下是会涉及的布尔变量，以及其默认值：

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【位置DbPersistenceService】

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Connection connection = null;  boolean mustConnectionBeClosed = false;  Transaction transaction = null;  boolean isTransactionEnabled = true;  boolean isCurrentSessionEnabled = false;  boolean isRollbackOnly = false;  Session session;  boolean mustSessionBeFlushed = false;boolean mustSessionBeClosed = false;

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准备工作2）由于DbPersistenceService只有一个Constructor，也就是

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【位置DbPersistenceService】

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public DbPersistenceService(DbPersistenceServiceFactory persistenceServiceFactory) {    this.persistenceServiceFactory = persistenceServiceFactory;    this.isTransactionEnabled = persistenceServiceFactory.isTransactionEnabled();    this.isCurrentSessionEnabled = persistenceServiceFactory.isCurrentSessionEnabled();  }

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public Session getSession() { if ( (session==null) && (getSessionFactory()!=null) ) { Connection connection = getConnection(false); if (isCurrentSessionEnabled) { session = getSessionFactory().getCurrentSession(); mustSessionBeClosed = false; mustSessionBeFlushed = false; mustConnectionBeClosed = false; } else if (connection!=null) { log.debug("creating hibernate session with connection "+connection); session = getSessionFactory().openSession(connection); mustSessionBeClosed = true; mustSessionBeFlushed = true; mustConnectionBeClosed = false; } else { log.debug("creating hibernate session"); session = getSessionFactory().openSession(); mustSessionBeClosed = true; mustSessionBeFlushed = true; mustConnectionBeClosed = false; } if (isTransactionEnabled) { log.debug("beginning hibernate transaction"); transaction = session.beginTransaction(); } } return session; }

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因为注入到JbpmContext的session和sessionFactory Setter方法都是将其注入到persistenceService里面的?在上面这个方法里