看似是一個variable有name和mapped-name兩個名稱,其實情況很複雜。看例子。
假定我們有一個極其簡單的流程vartest (surprisingly it also means V-Artest, but i must say that i'm not a Laker fan) 。在start-state的controller裏添加一個variable,name爲"var",mapped-name爲"variable",如下:
<?xml version="1.0" encoding="UTF-8"?> <process-definition xmlns="" name="vartest"> <start-state name="start-state1"> <task> <controller> <variable access="read,write" name="var" mapped-name="variable"></variable> </controller> </task> <transition to="task-node1"></transition> </start-state> <task-node name="task-node1" <transition to="end-state1"></transition> </task-node> <end-state name="end-state1"></end-state> </process-definition>
然後我們來寫一個Test Case:
public class AccessVariable extends TestCase
{
public void testPayProcess() throws Exception
{
JbpmContext jc = JbpmConfiguration.getInstance().
createJbpmContext();
ProcessDefinition pd = jc.getGraphSession().
findLatestProcessDefinition("vartest");
ProcessInstance pi = pd.createProcessInstance();
ContextInstance ci = pi.getContextInstance();
TaskInstance ti = pi.getTaskMgmtInstance().createStartTaskInstance()
//hint 1:
//ci can create new variable (not declared in <controller>)
//and ti can access the variable ci created
ci.setVariable("abc", "ABC");
System.out.println(ti.getVariable("abc")); //ABC
ti.setVariable("abc", "CBA");
System.out.println(ci.getVariable("abc")); //CBA
//hint 1:
//also, ti can create this kind of variables
//and ci can access the variable ti created
ti.setVariable("def", "DEF");
System.out.println(ci.getVariable("def")); //DEF
ci.setVariable("def", "FED");
System.out.println(ti.getVariable("def")); //FED
//hint 2:
//for the variables declared in <controller>, it's the same situation
//both ci and ti can create and access this kind of variable
ci.setVariable("var", "VAR");
System.out.println(ti.getVariable("var")); //VAR
ti.setVariable("var", "RAV");
System.out.println(ci.getVariable("var")); //RAV
//hint 3:
//"var" doesn't affect "variable"
System.out.println(ti.getVariable("variable")); //null
System.out.println(ci.getVariable("variable")); //null
//hint 4:
//things becaome a little different when using mapped-name
ti.setVariable("variable", "VARIABLE");
System.out.println(ti.getVariable("variable")); //VARIABLE
System.out.println(ci.getVariable("variable")); //null
//hint 4:
//it's clear that ti and ci both holds an "variable", respectively
ci.setVariable("variable", "ELBAIRAV");
System.out.println(ti.getVariable("variable")); //VARIABLE
System.out.println(ci.getVariable("variable")); //ELBAIRAV
//hint 3:
//and "variable" doesn't affect "var"
System.out.println(ti.getVariable("var")); //RAV
System.out.println(ci.getVariable("var")); //RAV
ti.end();
pi.end();
jc.close();
}
}
輸出結果如註釋所示。
可以看出,除了mapped-name之外,ti和ci可以隨意SetVariable(key, value),SetVariable的過程包含了create的過程,key可以是name,也可以是其他字符串,且這種類型的變量(名稱爲name或是任意字符串,只要不是mapped-name)ti和ci可以隨意訪問,這類變量對ti和ci的作用域是一樣的(類似於全局變量)。
但name和mapped-name變量沒有任何關係,如hint 3所示,"var"的值不會影響"variable",反過來"variable"的值也不會影響"var"。
且mapped-name變量對ti和ci來說更像是2個變量,其作用域嚴格區分,沒有任何交集,如hint 4所示。