Java工作流引擎 JBoss jBPM 3.1.2 演示示例

jBPM是由JBoss开发的工作流和业务流程管理引擎，可以用于创建不同人、不同应用程序、不同服务之间交互的业务流程。jBPM还提供了一个可视化的业务流程设计器。jBPM包含下列组件：运行时引擎（一个POJO库），图形化设计器（一个Eclipse插件），基于Hibernate的持久化，基于JSF的web控制台，BPEL扩展等。

Hello World示例

流程定义是一个可管理的包含了节点和节点间交付件的流程图。Hello World示例流程包含三个节点。为了查看节点间如何相互配合，将不使用任何设计工具来定义一个简单的流程。下图显示了Hello World示例流程的流程图定义：

Hello World示例流程图

public void testHelloWorldProcess() {
ProcessDefinition processDefinition = ProcessDefinition.parseXmlString(
"<process-definition>" +<br>" <start-state>" +<br>" <transition to="s"></transition>" +<br>" </start-state>" +<br>" <state name="s">" +<br>" <transition to="end"></transition>" +<br>" </state>" +<br>" <end-state name="end"></end-state>" +<br>"</process-definition>"
);
ProcessInstance processInstance = new ProcessInstance(processDefinition);
Token token = processInstance.getRootToken();
assertSame(processDefinition.getStartState(), token.getNode());
token.signal();
assertSame(processDefinition.getNode("s"), token.getNode());
token.signal();
assertSame(processDefinition.getNode("end"), token.getNode());
}

数据库示例

jBPM基本特性之一是能够在jBPM数据库中持久化执行过程中处于等待状态的流程。数据库示例将展示如何在jBPM数据库中存储一个流程实例。该示例可能涉及到jBPM上下文。为不同的用户代码创建Separate方法。举例来说，webapplication中的一段用户代码开始一个流程并在数据库中持久化。之后，一个消息驱动Bean（MDB）加载该流程实例继续执行流程。

public class HelloWorldDbTest extends TestCase {
static JbpmConfiguration jbpmConfiguration = null;
static {
jbpmConfiguration = JbpmConfiguration.parseXmlString(
"<jbpm-configuration>" +<br> " <jbpm-context>" +<br> " <service name="persistence"></service> " factory='org.jbpm.persistence.db.DbPersistenceServiceFactory' /&gt;" + <br> " </jbpm-context>" +<br> " <string name="resource.hibernate.cfg.xml"></string> " value='hibernate.cfg.xml' /&gt;" +<br> " <string name="resource.business.calendar"></string> " value='org/jbpm/calendar/jbpm.business.calendar.properties' /&gt;" +<br> " <string name="resource.default.modules"></string> " value='org/jbpm/graph/def/jbpm.default.modules.properties' /&gt;" +<br> " <string name="resource.converter"></string> " value='org/jbpm/db/hibernate/jbpm.converter.properties' /&gt;" +<br> " <string name="resource.action.types"></string> " value='org/jbpm/graph/action/action.types.xml' /&gt;" +<br> " <string name="resource.node.types"></string> " value='org/jbpm/graph/node/node.types.xml' /&gt;" +<br> " <string name="resource.varmapping"></string> " value='org/jbpm/context/exe/jbpm.varmapping.xml' /&gt;" +<br> "</jbpm-configuration>"
);
}
public void setUp() {
jbpmConfiguration.createSchema();
}
public void tearDown() {
jbpmConfiguration.dropSchema();
}
public void testSimplePersistence() {
deployProcessDefinition();
processInstanceIsCreatedWhenUserSubmitsWebappForm();
theProcessInstanceContinuesWhenAnAsyncMessageIsReceived();
}
public void deployProcessDefinition() {
ProcessDefinition processDefinition = ProcessDefinition.parseXmlString(
"<process-definition name="hello world">" +<br> " <start-state name="start">" +<br> " <transition to="s"></transition>" +<br> " </start-state>" +<br> " <state name="s">" +<br> " <transition to="end"></transition>" +<br> " </state>" +<br> " <end-state name="end"></end-state>" +<br> "</process-definition>"
);
JbpmContext jbpmContext = jbpmConfiguration.createJbpmContext();
try {
jbpmContext.deployProcessDefinition(processDefinition);

} finally {
jbpmContext.close();
}
}
public void processInstanceIsCreatedWhenUserSubmitsWebappForm() {
JbpmContext jbpmContext = jbpmConfiguration.createJbpmContext();
try {
GraphSession graphSession = jbpmContext.getGraphSession();
ProcessDefinition processDefinition =graphSession.findLatestProcessDefinition("hello world");
ProcessInstance processInstance = new ProcessInstance(processDefinition);
Token token = processInstance.getRootToken();
assertEquals("start", token.getNode().getName());
token.signal();
assertEquals("s", token.getNode().getName());
jbpmContext.save(processInstance);
} finally {
jbpmContext.close();
}
}
public void theProcessInstanceContinuesWhenAnAsyncMessageIsReceived() {
JbpmContext jbpmContext = jbpmConfiguration.createJbpmContext();
try {
GraphSession graphSession = jbpmContext.getGraphSession();
ProcessDefinition processDefinition =graphSession.findLatestProcessDefinition("hello world");
List processInstances =graphSession.findProcessInstances(processDefinition.getId());
ProcessInstance processInstance =(ProcessInstance) processInstances.get(0);
processInstance.signal();
assertTrue(processInstance.hasEnded());
jbpmContext.save(processInstance);
} finally {
jbpmContext.close();
}
}
}

上下文示例：流程变量

流程变量包含了流程执行期间的上下文信息。流程变量类似一个java.util.Map类型的名称/值对，并且是java对象。流程变量是流程实例的组成部分。以免事件复杂化，该示例仅仅演示处理流程变量的API，没有包括持久化处理。

ProcessDefinition processDefinition = ProcessDefinition.parseXmlString(
"<process-definition>" +<br> " <start-state>" +<br> " <transition to="s"></transition>" +<br> " </start-state>" +<br> " <state name="s">" +<br> " <transition to="end"></transition>" +<br> " </state>" +<br> " <end-state name="end"></end-state>" +<br> "</process-definition>"
);

ProcessInstance processInstance = new ProcessInstance(processDefinition);
ContextInstance contextInstance = processInstance.getContextInstance();
contextInstance.setVariable("amount", new Integer(500));
contextInstance.setVariable("reason", "i met my deadline");
processInstance.signal();
assertEquals(new Integer(500), contextInstance.getVariable("amount"));
assertEquals("i met my deadline", contextInstance.getVariable("reason"));

任务分配示例

任务分配示例演示如何给用户分配任务。因为分离jBPM工作流引擎和组织模型，处理参与者的表现语言始终受到很多限制。因此，你必须实现一个包含处理任务参与者的任务分配器。

public void testTaskAssignment() {
ProcessDefinition processDefinition = ProcessDefinition.parseXmlString(
"<process-definition name="the baby process">" +<br> " <start-state>" +<br> " <transition name="baby cries" to="t"></transition>" +<br> " </start-state>" +<br> " <task-node name="t">" +<br> " <task name="change nappy">" +<br> " <assignment class="org.jbpm.tutorial.taskmgmt.NappyAssignmentHandler"></assignment>" +<br> " </task>" +<br> " <transition to="end"></transition>" +<br> " </task-node>" +<br> " <end-state name="end"></end-state>" +<br> "</process-definition>"
);
ProcessInstance processInstance =
new ProcessInstance(processDefinition);
Token token = processInstance.getRootToken();
token.signal();
assertSame(processDefinition.getNode("t"), token.getNode());
TaskInstance taskInstance = (TaskInstance)processInstance
.getTaskMgmtInstance()
.getTaskInstances()
.iterator().next();
assertEquals("papa", taskInstance.getActorId() );
taskInstance.end();
assertSame(processDefinition.getNode("end"), token.getNode());
}

JBoss jBPM 3.1 Workflow and BPM made practical

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