（一）結構:
(1)XML定義文件(definition)
(2)plain java JBpm對象模型 定義 執(zhí)行 日志
(3)DataBase 定義 執(zhí)行 日志
（二）
A process definition can be represented in 3 different forms : as xml, as java objects and as records in the jBPM database. Executional (=runtime) information and logging information can be represented in 2 forms : as java objects and as records in the jBPM database.{一個流程定義可以表現(xiàn)為三種不同的形態(tài)：XML 、java對象和jBpm數(shù)據(jù)庫中的記錄。執(zhí)行（運行）信息和日志信息可以表現(xiàn)為兩種形態(tài)：java對象和jBpm數(shù)據(jù)庫中的記錄}
For more information about the xml representation of process definitions and process archives, see Chapter 13, jBPM Process Definition Language (JPDL).{Process Definition Language JPDL}
This chapter will discuss the transformations done between the java objects and the jBPM database. To store java objects in the database and retrieve them, jBPM uses hibernate internally. While it is not strictly necessary to have hibernate knowledge for using jBPM, it is recommended. {這個章節(jié)將要討論在java對象和jBPM數(shù)據(jù)庫之間的轉換。為了在數(shù)據(jù)庫中存儲對象和獲取他們，jBPM使用內(nèi)部使用了Hibernate。當然不是在使用jBPM中嚴格要擁有Hibernate的知識，它是建議的}
More information on how to deploy a process archive to the database can be found in Section 13.1.1, “Deploying a process archive” .
（三）Session的層次：
JbpmSessionFactory
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JbpmSession
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GraphSession
TaskMgmtSession
ContextSession
（四） The jBPM database classes
The jBPM persistence operations can be found in the named sessions like e.g. GraphSession, TaskMgmtSession and ContextSession,... The named sessions can be obtained from a JbpmSession. The JbpmSession in its turn can be obtained from a JbpmSessionFactory. {jBPM持久層操作可以發(fā)現(xiàn)被命名為sessions,例如想GraphSession TaskMgmtSession和ContextSession.... 這個命名sessions可以從JbpmSession中獲得。JbmpSession可以從JbpmSessionFactory中獲得}
A JbpmSessionFactory is threadsafe so in your application, you need one JbpmSessionFactory. That singleton can be referenced e.g. in a static variable with lazy initialization (beware about the issues around lazy initialization and double-checked locking). At creation time, the JbpmSessionFactory prepares all information in a way that JbpmSessions can be created super fast. {一個JbpmSessionFactory在你的程序中是線程安全的，你僅僅需要一個JbpmSessionFactory. 那個單例可以被參考在例如在lazy初始化下的靜態(tài)變量（小心發(fā)布在Lazy 初始化并且雙層檢查鎖定。在創(chuàng)建時刻，JbpmSessionFactory 在某種程度準備所有信息那樣可以被快速創(chuàng)建）}
As a user, you should create one JbpmSession per thread or per request. The JbpmSession has a JDBC connection to the database. {作為一個用戶，你應該創(chuàng)建一個JbpmSession 每一個線程或每一次請求。JbpmSession擁有一個連接數(shù)據(jù)庫的Jdbc連接。}
The purpose of the JbpmSession and JbpmSessionFactory is only to wrap their hibernate counterparts. For advanced features such as detached objects or optimistic locking, see the hibernate documentation. {這個JbpmSession和JbpmSessionFactory的目的僅僅是為了包裝Hibernate 副本。 對于高級特征 例如分離對象或樂觀鎖，看hibernate文檔。}
public class PersistenceApiTest extends TestCase {
static JbpmSessionFactory jbpmSessionFactory = JbpmSessionFactory.buildJbpmSessionFactory();
public void testStartProcessInstance() {
// obtain a session
JbpmSession jbpmSession = jbpmSessionFactory.openJbpmSession();
try {
// start a user managed transaction
jbpmSession.beginTransaction();
// load information from the database
// (note that process definitions will be cached in memory
// in the second level cache of hibernate)
ProcessDefinition auctionProcess =
jbpmSession.getGraphSession().findLatestProcessDefinition("auction");
// perform a POJO workflow operation on the plain object model.
ProcessInstance auctionInstance = new ProcessInstance(auctionProcess);
auctionInstance.signal();
// store the result in the database
jbpmSession.getGraphSession().saveProcessInstance(auctionInstance);
// commit the user transaction
jbpmSession.commitTransaction();
} finally {
// close the session.
jbpmSession.close();
}
}
}