The goal is to create a program, which prints out an overview of cross-links within an XML document formatted as a DocBook. The program reads the DocBook document from the standard input and writes to the standard output, it prints out an overview of cross-links with the names of sections among which the cross-links point.
The cross-links are created via the <link> element. The cross-link target is a unique
ID in the linkend attribute. The document is structured into sections that are
denoted by the <section> element. Each section has its title specified in the <title>
element. Sections can be arbitrarily nested. Cross-links are always in a section;
the same is true for cross-links targets.
The program prints out a list of cross-links grouped by a section, in which the cross-link is located. For each cross-link, the program prints out a text of the cross-link and the title of a section, in which the cross-link target is located (the cross-link is indented by 4 spaces). For example, if there is a cross-link with the text "see in section ABC" from section "XYZ" to section "ABC", then the program prints out
XYZ:
see in section ABC (ABC)
The size of the input document can be up to tens of megabytes. Assume that the input document is always a valid XML and has the above described structure. The XML document does not contain any namespaces (i.e., all the elements and attributes are without any prefix).
Used the JDOM library.