使用JBPM实现动态会签

目前有很多实现动态会签的文章，但是给人感觉不是很优雅，下面介绍一种实现方式。
1、流程定义文件：

xml 代码

<
process-definition
xmlns
=
"urn:jbpm.org:jpdl-3.1"
 
name
=
"foreach"
>
<
start-state
 
name
=
"start"
>
<
task
 
name
=
"one"
>
</
task
>
<
transition
 
name
=
"a"
 
to
=
"foreachf"
>
</
transition
>
</
start-state
>
<
node
 
name
=
"foreachf"
>
<
action
 
class
=
"com.framework.workflow.jbpm.ForEachFork"
>
<
foreach
>
#{bpm_assignees}
</
foreach
>
<
var
>
reviewer
</
var
>
</
action
>
<
transition
 
name
=
"review"
 
to
=
"review"
>
</
transition
>
</
node
>
<
task-node
 
name
=
"review"
>
<
task
 
name
=
"reviewTask"
>
<
assignment
 
class
=
"com.framework.workflow.jbpm.DefaultAssignment"
>
<
actor
>
#{reviewer}
</
actor
>
</
assignment
>
</
task
>
<
transition
 
name
=
"reject"
 
to
=
"endreview"
>
<
action
 
class
=
"com.framework.workflow.jbpm.JoinEndForkedTokens"
 
/>
</
transition
>
<
transition
 
name
=
"approve"
 
to
=
"endreview"
>
</
transition
>
</
task-node
>
<
join
 
name
=
"endreview"
>
<
transition
 
name
=
"toend"
 
to
=
"end1"
>
</
transition
>
</
join
>
<
end-state
 
name
=
"end1"
>
</
end-state
>
</
process-definition
>

在这里我们从node节点动态生成任务节点，会签时当有一个是reject时便结束所有节点。
2、动态派生ForEachFork代码：

java 代码

public
 
class
 ForEachFork 
implements
 ActionHandler
{
private
 Element foreach;
private
 String var;
//测试数据
private
 
static
 Map map = 
new
 HashMap();
static
{
List list = new
 ArrayList();
list.add("1234"
);
list.add("2345"
);
list.add("3456"
);
map.put("bpm_assignees"
, list);
}

/**
*

为每个元素创建一个分支

*
* @param executionContext
* @throws Exception
*/
@SuppressWarnings
(
"unchecked"
)
public
 
void
 execute(
final
 ExecutionContext executionContext)
throws
 Exception
{


if
 (foreach == 
null
)
{
throw
 
new
 WorkflowException(
"forEach has not been provided"
);
}

List forEachColl = null
;
String forEachCollStr = foreach.getTextTrim();

if
 (forEachCollStr != 
null
)
{
if
 (forEachCollStr.startsWith(
"#{"
))
{
String expression = forEachCollStr.substring(2
, forEachCollStr.length() -
1
);
forEachColl = (List)map.get(expression);

}

}

if
 (var == 
null
 || var.length() == 
0
)
{
throw
 
new
 WorkflowException(
"forEach variable name has not been provided"
);
}

//
// 创建分支
//

Token rootToken = executionContext.getToken();
Node node = executionContext.getNode();
List forkTransitions = new
 ArrayList();
// 为每一个元素创建一个token
for
 (
int
 i = 
0
; i < node.getLeavingTransitions().size(); i++)
{
Transition transition = (Transition) node.getLeavingTransitions().get(i);
for
 (
int
 iVar = 
0
; iVar < forEachColl.size(); iVar++)
{
// 为每一个新token创建一个path
String tokenName = getTokenName(rootToken, transition.getName(), iVar);
Token loopToken = new
 Token(rootToken, tokenName);
loopToken.setTerminationImplicit(true
);
executionContext.getJbpmContext().getSession().save(loopToken);

//赋予一个新变量
final
 ExecutionContext newExecutionContext = 
new
 ExecutionContext(loopToken);
newExecutionContext.getContextInstance().createVariable(var, forEachColl.get(iVar), loopToken);

// 记录下每一transition
ForkedTransition forkTransition = new
 ForkedTransition();
forkTransition.executionContext = newExecutionContext;
forkTransition.transition = transition;
forkTransitions.add(forkTransition);
}
}
//
// 转向下一个节点
//
for
 (ForkedTransition forkTransition : forkTransitions)
{
node.leave(forkTransition.executionContext, forkTransition.transition);
}
}
/**
*

获得分支token name

*
* @param parent
* @param transitionName
* @return
*/
protected
 String getTokenName(Token parent, String transitionName, 
int
 loopIndex)
{
String tokenName = null
;
if
 (transitionName != 
null
)
{
if
 (!parent.hasChild(transitionName))
{
tokenName = transitionName;
}
else
{
int
 i = 
2
;
tokenName = transitionName + Integer.toString(i);
while
 (parent.hasChild(tokenName))
{
i++;
tokenName = transitionName + Integer.toString(i);
}
}
}
else
{
// 没有转向
int
 size = ( parent.getChildren()!=
null
 ? parent.getChildren().size()+
1
 : 
1
 );
tokenName = Integer.toString(size);
}
return
 tokenName + 
"."
 + loopIndex;
}



/**
* Fork Transition
*/
private
 
class
 ForkedTransition
{
private
 ExecutionContext executionContext;
private
 Transition transition;
}
}

 

 

在具体应用中需要灵活的根据业务逻辑需要派生所需要的分支。

 

3、DefaultAssignment
进行简单的权限操作，这里面主要是将#{reviewer}值作为actorId进行设置
4、JoinEndForkedTokens结束所有节点

java 代码

public
 
class
 JoinEndForkedTokens 
implements
 ActionHandler
{

public
 JoinEndForkedTokens()
{
}
/* (non-Javadoc)
* @see org.jbpm.graph.def.ActionHandler#execute(org.jbpm.graph.exe.ExecutionContext)
*/
public
 
void
 execute(ExecutionContext executionContext)
{
Token token = executionContext.getToken().getParent();
Map childTokens = token.getActiveChildren();
for
 (Object childToken : childTokens.values())
{
cancelToken(executionContext, (Token)childToken);
}

}
/**
*

取消 token

*
* @param executionContext
* @param token
*/
protected
 
void
 cancelToken(ExecutionContext executionContext, Token token)
{

Map childTokens = token.getActiveChildren();
for
 (Object childToken : childTokens.values())
{
cancelToken(executionContext, (Token)childToken);
}

if
 (!token.hasEnded())
{
token.end(true
);
}


cancelTokenTasks(executionContext, token);
}
/**
*

结束token关联的任务

*
* @param executionContext
* @param token
*/
protected
 
void
 cancelTokenTasks(ExecutionContext executionContext, Token token)
{
TaskMgmtInstance tms = executionContext.getTaskMgmtInstance();
Collection tasks = tms.getUnfinishedTasks(token);
for
 (Object task : tasks)
{
TaskInstance taskInstance = (TaskInstance)task;
if
 (taskInstance.isBlocking())
{
taskInstance.setBlocking(false
);
}
if
 (taskInstance.isSignalling())
{
taskInstance.setSignalling(false
);
}
if
 (!taskInstance.hasEnded())
{
taskInstance.end();
}
}
}
}

 

 

结束所有分支节点任务，流向结束节点。

 

评论

4 楼 rebellan 2008-07-18  

太感谢楼主的分享精神了，搞了好久的会签 被楼主点通了，谢谢

3 楼 zhumaohua 2008-02-21  

        

2 楼 llandyl 2007-12-04  

问题已经解决。是测试程序测试方法不对造成的。

1 楼 llandyl 2007-12-03  

如果将流程定义文件修改，变成两次调用生成<node name="foreachf">就会有错误，而不是直接结束。
错误出现在 executionContext.getJbpmContext().getSession().save(loopToken);  
。通过跟踪发现，是executionContext.getJbpmContext()为空。即报Caused by: java.lang.NullPointerException的错误。
这个问题困扰我几天了。一致没有解决。
不知那位有过此情况下的情况，望告知。谢谢！