public JoinMode buildJoinStrategy(String mode) {
if(Constants.JOIN_ALL.equalsIgnoreCase(mode))
return new AllJoinMode();
else if(Constants.JOIN_MULTI.equalsIgnoreCase(mode))
return new MultiJoinMode();
else if(Constants.JOIN_SINGLE.equalsIgnoreCase(mode))
return new SingleJoinMode();
else
throw new ProcessEngineException("聚合模式值不正确,Mode="+mode);
}