JBPM3中文用户手册——第三章：教程(3)

3.3    上下文示例：流程变量

流程变量（process variable）包含流程执行时的上下文（context）信息。它类似于一个java.util.Map，映射变量名称到java对象值。流程变量被作为流程的一部分持久。为了简化，下面这个例子中，我们只展示了操作变量的API，没有展示如何持久。

 

更多关于变量的信息，参考11.上下文。

 

// This example also starts from the hello world process.

// This time even without modification.

ProcessDefinition processDefinition = ProcessDefinition.parseXmlString(

  "<process-definition>" +

  "  <start-state>" +

  "    <transition to='s' />" +

  "  </start-state>" +

  "  <state name='s'>" +

  "    <transition to='end' />" +

  "  </state>" +

  "  <end-state name='end' />" +

  "</process-definition>"

);

 

ProcessInstance processInstance =

  new ProcessInstance(processDefinition);

 

// Fetch the context instance from the process instance

// for working with the process variables.

ContextInstance contextInstance =

  processInstance.getContextInstance();

 

// Before the process has left the start-state,

// we are going to set some process variables in the

// context of the process instance.

contextInstance.setVariable("amount", new Integer(500));

contextInstance.setVariable("reason", "i met my deadline");

 

// From now on, these variables are associated with the

// process instance.  The process variables are now accessible

// by user code via the API shown here, but also in the actions

// and node implementations.  The process variables are also 

// stored into the database as a part of the process instance.

 

processInstance.signal();

 

// The variables are accessible via the contextInstance.

 

assertEquals(new Integer(500),

             contextInstance.getVariable("amount"));

assertEquals("i met my deadline",

             contextInstance.getVariable("reason"));