Parser


Object Hierarchy:

Object hierarchy for Parser

Description:

public class Parser : Object

JSON data streams parser.

The contents of the Parser structure are private and should only be accessed via the provided API.

Example: Parser example (data):

public errordomain MyError {
INVALID_FORMAT
}

public static void process_role (Json.Node node, uint number) throws Error {
if (node.get_node_type () != Json.NodeType.OBJECT) {
throw new MyError.INVALID_FORMAT ("Unexpected element type %s", node.type_name ());
}

// TODO, type check ...
unowned Json.Object obj = node.get_object ();
unowned string first = null;
unowned string last = null;

foreach (unowned string name in obj.get_members ()) {
switch (name) {
case "firstName":
unowned Json.Node item = obj.get_member (name);
if (item.get_node_type () != Json.NodeType.VALUE) {
throw new MyError.INVALID_FORMAT ("Unexpected element type %s", item.type_name ());
}

first = obj.get_string_member ("firstName");
break;

case "lastName":
unowned Json.Node item = obj.get_member (name);
if (item.get_node_type () != Json.NodeType.VALUE) {
throw new MyError.INVALID_FORMAT ("Unexpected element type %s", item.type_name ());
}

last = obj.get_string_member ("lastName");
break;

default:
throw new MyError.INVALID_FORMAT ("Unexpected element '%s'", name);
}
}

if (first == null || last == null) {
throw new MyError.INVALID_FORMAT ("Expected: firstName, lastName");
}

print ("\t%s %s\n", first, last);
}

public static void process_role_array (Json.Node node) throws Error {
if (node.get_node_type () != Json.NodeType.ARRAY) {
throw new MyError.INVALID_FORMAT ("Unexpected element type %s", node.type_name ());
}

unowned Json.Array array = node.get_array ();
int i = 1;

foreach (unowned Json.Node item in array.get_elements ()) {
process_role (item, i);
i++;
}
}

public static void process_good (Json.Node node) throws Error {
print ("Good:\n");
process_role_array (node);
}

public static void process_bad (Json.Node node) throws Error {
print ("Bad:\n");
process_role_array (node);
}

public static void process (Json.Node node) throws Error {
if (node.get_node_type () != Json.NodeType.OBJECT) {
throw new MyError.INVALID_FORMAT ("Unexpected element type %s", node.type_name ());
}

unowned Json.Object obj = node.get_object ();

foreach (unowned string name in obj.get_members ()) {
switch (name) {
case "good":
unowned Json.Node item = obj.get_member (name);
process_good (item);
break;

case "bad":
unowned Json.Node item = obj.get_member (name);
process_bad (item);
break;

default:
throw new MyError.INVALID_FORMAT ("Unexpected element '%s'", name);
}
}
}

public static int main (string[] args) {
// Json: (Array: [], Object: {})
string data =
"""
{
"good" : [
{ "firstName" : "Marty",
"lastName" : "McFly" },

{ "firstName" : "Emmett",
"lastName" : "Brown" }
],
"bad" : [
{ "firstName" : "Biff",
"lastName" : "Green" }
]
}
"""
;

// Parse:
Json.Parser parser = new Json.Parser ();
try {
parser.load_from_data (data);

// Get the root node:
Json.Node node = parser.get_root ();

// Process (print) the file:
process (node);
} catch (Error e) {
print ("Unable to parse the string: %s\n", e.message);
return -1;
}
return 0;
}

valac --pkg json-glib-1.0 parser-example-data.vala


Namespace: Json
Package: json-glib-1.0

Content:

Properties:

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Inherited Members: