解析xml以构造从源到目标的路径

Question

需要一种方法从xml中获取详细信息以构建从源到目标的路径。

例如：

<CONNECTOR FROMFIELD ="col1" FROMINSTANCE ="table1"  TOFIELD ="col1" TOINSTANCE ="table4" />
<CONNECTOR FROMFIELD ="col2" FROMINSTANCE ="table2"  TOFIELD ="col2" TOINSTANCE ="table3" />
<CONNECTOR FROMFIELD ="col4" FROMINSTANCE ="table4"  TOFIELD ="col4" TOINSTANCE ="table2" />

应该作为输出：table1->table4->table2->table3

与表中可用的列相同，因为映射是表中的列级别  table1.col1->table4.col4->table2.col2->table3.col3