protected String[] findActiveNodes() {
		StringBuilder buffer = new StringBuilder(20);
		findForkTaskNames(model, buffer);
		String[] taskNames = buffer.toString().split(",");
		return taskNames;
	}
protected String[] findActiveNodes() {
		StringBuilder buffer = new StringBuilder(20);
		findForkTaskNames(model, buffer);
		String[] taskNames = buffer.toString().split(",");
		return taskNames;
	}
protected String [ ] findActiveNodes ( ) { StringBuilder buffer = new StringBuilder ( 20 ) ; findForkTaskNames ( model , buffer ) ; String [ ] taskNames = buffer . toString ( ) . split ( "," ) ; return taskNames ; }
对join节点的所有输入变迁进行递归，查找join至fork节点的所有中间task元素
@see org.snaker.engine.handlers.impl.AbstractMergeHandler#findActiveNodes()
对join节点的所有输入变迁进行递归，查找join至fork节点的所有中间task元素