TextReader


Object Hierarchy:

Object hierarchy for TextReader

Description:

[ Compact ]
[ CCode ( cname = "xmlTextReader" , free_function = "xmlFreeTextReader" ) ]
public class TextReader

Example: TextReader: Streaming API:

<?xml version="1.0" encoding="utf-8"?>
<books>
<book id="1">
<title>The Royal Game</title>
<author>Stefan Zweig</author>
</book>
<book id="2">
<title>The Stoker</title>
<author>Franz Kafka</author>
</book>
</books>

public class Book : Object {
public string author { private set; get; }
public string title { private set; get; }
public int64 id { private set; get; }

public Book (int64 id, owned string author, owned string title) {
this.author = (owned) author;
this.title = (owned) title;
this.id = id;
}

public string to_string () {
return ("%"+int64.FORMAT+": %s, written by %s").printf (id, title, author);
}
}

public class BookReader : Object {
private SList<Book> books;
private Xml.TextReader reader;
private Xml.ReaderType current_type;
private unowned string filename;
private int status;

public SList<Book> read (string filename) throws FileError, MarkupError {
this.reader = new Xml.TextReader.filename (filename);
if (this.reader == null) {
throw new FileError.NOENT ("Unable to open %s\n", filename);
}

this.filename = filename;

next ();
read_books ();

if (status != 0) {
error ("failed to parse file");
}

return (owned) books;
}

private void error (string str) throws MarkupError {
int column = reader.get_parser_column_number ();
int line = reader.get_parser_line_number ();
throw new MarkupError.PARSE ("%s: %d.%d: %s", filename, line, column, str);
}

private void next () throws MarkupError {
status = reader.read ();
if (status == -1) {
error ("failed to parse file");
}

current_type = (Xml.ReaderType) reader.node_type ();
if (current_type == Xml.ReaderType.WHITESPACE || current_type == Xml.ReaderType.SIGNIFICANT_WHITESPACE) {
next ();
}
}

private bool is_start_element (string name) {
if (current_type != Xml.ReaderType.ELEMENT || reader.const_name () != name) {
return false;
}
return true;
}

private void start_element (string name) throws MarkupError {
if (current_type != Xml.ReaderType.ELEMENT || reader.const_name () != name) {
string got = (reader.const_name () != null)? ", got: " + reader.const_name () : "";
error ("expected start element of `%s'%s".printf (name, got));
}
}

private void end_element (string name) throws MarkupError {
if (current_type != Xml.ReaderType.END_ELEMENT || reader.const_name () != name) {
string got = (reader.const_name () != null)? ", got: " + reader.const_name () : "";
error ("expected end element of `%s'%s".printf (name, got));
}
next ();
}

private string text () throws MarkupError {
if (current_type != Xml.ReaderType.TEXT) {
string got = (reader.const_name () != null)? ", got: " + reader.const_name () : "";
error ("expected text" + got);
}

string content = reader.const_value ();
next ();

return content;
}

private int64 get_attr_int (string name) throws MarkupError {
string num_str = reader.get_attribute (name);
if (num_str == null) {
error ("expected id=\"<int>\"");
}

int64 id;

if (int64.try_parse (num_str, out id) == false) {
error ("expected id=\"<int>\"");
}

return id;
}

private void read_books () throws MarkupError {
start_element ("books");
next ();

while (is_start_element ("book")) {
read_book ();
}

end_element ("books");
}

private void read_book () throws MarkupError {
start_element ("book");
int64 id = get_attr_int ("id");
next ();

string title = read_title ();
string author = read_author ();

end_element ("book");

books.prepend (new Book (id, (owned) author, (owned) title));
}

private string read_title () throws MarkupError {
start_element ("title");
next ();

string title = text ();

end_element ("title");
return title;
}

private string read_author () throws MarkupError {
start_element ("author");
next ();

string author = text ();

end_element ("author");
return author;
}

public static int main (string[] args) {
try {
BookReader reader = new BookReader ();
SList<Book> books = reader.read ("books.xml");
books.foreach ((book) => {
print (book.to_string ());
print ("\n");
});
} catch (Error e) {
print ("Error: %s\n", e.message);
}
return 0;
}
}

valac --pkg libxml-2.0 xml-text-reader.vala


Namespace: Xml
Package: libxml-2.0

Content:

Creation methods:

Methods: