Re: [fpc-pascal] OOP and XML usage
using my system you can retrieve the text by a typecast mytag.first; mytag.findofclass(TXMLText); - will stop the search at the first object of specified class If mytag.child is TXMLText Then - to guarantee that we have found something WriteLn((mytag.child as TXMLText).Content); - will print the contents of the text or if you know the text position between the child tags writeln((mytag.childs[0] As TXMLText).Content); but this is a way quite harder than a simple WriteLn(mytag.properties['ip']); - will return the property or '' if not set (the object constructor can setup defaults) thats why i prefer tag properties instead of xml text... later you can save the objects with Var F : Text; Begin Assign(F, 'myfile.xml'); Rewrite(F); WriteLn(F, MyTag.AsXML); Close(F); End; 2010/1/29 Graeme Geldenhuys graemeg.li...@gmail.com: Jorge Aldo G. de F. Junior wrote: and actually i prefer to setup properties of objects using xml properties instead of xml text tcpserver ip=192.168.1.1 port=80/ instead of tcpserverip192.168.1.1/ipport80/port/tcpserver Both examples are valid XML, so I don't see any issue the way I am using it. My previous example was just that, an example. My actual XML uses both tag attributes and element text. The later is mainly used for longer text in my xml file. Regards, - Graeme - -- fpGUI Toolkit - a cross-platform GUI toolkit using Free Pascal http://opensoft.homeip.net/fpgui/ ___ fpc-pascal maillist - fpc-pas...@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] OOP and XML usage
with my system would be simply something like
Type
TMyClass = Class(TXMLNode)
Private
fSomething : String;
Public
Constructor Create(Const aInstanceName : String); Override;
Class Function XMLTag: String; Override;
Published
Property Something : String Read fSomething Write fSomething;
End;
Constructor Create(Const aInstaceName : String);
Begin
Inherited Create(aInstanceName);
End;
Class Function XMLTag: String;
Begin
Result := 'MyTag';
End;
Factory.Register(TMyClass);
Whenever the xml loader finds a mytag something=test/ it will
create an instance of TMyClass and set the published properties
accordingly (Using RTTI)...
Theres another procedure (wich is virtual and can be overriden if
needed) that triggers events across the three... (wich are basically
dotted notation names...)
MyClass1.MyClass2.Test -
Finds instance MyClass1,
Finds instance MyClass2 that is a child of MyClass1
then issues a DispatchStr in MyClass1 with Test as the message
string... (The pointer can be passed as to hold properties, values,
etc)...
(Im using this message system to allow brower events to be sent to
server side objects)
2010/1/27 Anthony Walter sys...@gmail.com:
I've written some XML classes which expose themselves as interfaces.
Usage goes something like this:
procedure SaveSettings(const Settings: string);
var
Document: IDocument;
Filer: IFiler;
begin
Document := CreateDocument;
Filer := Document.ForceRoot('test') as IFiler;
Filer.WriteTime('time', Now);
Filer.WriteString('application', Application.ExeName);
Document.SaveToFile(Settings);
end;
testtime21:11:17/timeapplicationtest.exe/application/test
procedure ShowPerson;
var
Document: IDocument;
Root: INode;
begin
Document := CreateDocument;
Filer := Document.ForceRoot('data');
Root.ForceNode('person/age').Value = 17;
Root.FindNode('person[age = 17]').Filer.Write('Jason');
Root.Filer.Write('person/salary', 1);
ShowMessage(Document.Text);
end;
datapersonage17/agenameJason/namesalary1/salary/persondata
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Re: [fpc-pascal] OOP and XML usage
On Thu, 28 Jan 2010, Jorge Aldo G. de F. Junior wrote: im actually needing better RTTI as to allow easier method invocation... But generally i feel my way of doing XML is better than FPC defaults (Too generic, tries to solve too many problems with the same code) What exactly do you mean by FPC defaults ? Michael. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] OOP and XML usage
On 28 January 2010 16:10, Jorge Aldo G. de F. Junior jagf...@gmail.com wrote: Whenever the xml loader finds a mytag something=test/ it will create an instance of TMyClass and set the published properties accordingly (Using RTTI)... I like that idea, but how flexible is? By that I mean, I have nested tags (using the same element name) that I need to load. Something like a dependency tree. My custom object model can handle this without problems, but I'm still curious about your solution. Example XML, and there isn't a limit to the nesting of options. install optionOption 1/option optionBase database support optionFirebird drivers optionWindows/option optionLinux/option /option optionMySQL drivers/option /option /install -- Regards, - Graeme - ___ fpGUI - a cross-platform Free Pascal GUI toolkit http://opensoft.homeip.net/fpgui/ ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] OOP and XML usage
each tag generates a new instance of the class you can add a property (that all objects have) called InstanceName option instancename=blablasomething/option using the instance name the class factory can differentiate from other instances (factory.instance['blabla'] retrieves the correct instance, or, factory.dotnotation['roottag.nexttag.blabla'] retrieves by dotted notation.. or if you dont specify an instance name the factory will generate one randonly... and actually i prefer to setup properties of objects using xml properties instead of xml text tcpserver ip=192.168.1.1 port=80/ instead of tcpserverip192.168.1.1/ipport80/port/tcpserver 2010/1/28 Graeme Geldenhuys graemeg.li...@gmail.com: On 28 January 2010 16:10, Jorge Aldo G. de F. Junior jagf...@gmail.com wrote: Whenever the xml loader finds a mytag something=test/ it will create an instance of TMyClass and set the published properties accordingly (Using RTTI)... I like that idea, but how flexible is? By that I mean, I have nested tags (using the same element name) that I need to load. Something like a dependency tree. My custom object model can handle this without problems, but I'm still curious about your solution. Example XML, and there isn't a limit to the nesting of options. install optionOption 1/option optionBase database support optionFirebird drivers optionWindows/option optionLinux/option /option optionMySQL drivers/option /option /install -- Regards, - Graeme - ___ fpGUI - a cross-platform Free Pascal GUI toolkit http://opensoft.homeip.net/fpgui/ ___ fpc-pascal maillist - fpc-pas...@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] OOP and XML usage
i mean that FPC-XML tries to be too general and this leads to too cumbersome code in various situations (FPC-XML is clearly overkill for my needs). 2010/1/28 Michael Van Canneyt mich...@freepascal.org: On Thu, 28 Jan 2010, Jorge Aldo G. de F. Junior wrote: im actually needing better RTTI as to allow easier method invocation... But generally i feel my way of doing XML is better than FPC defaults (Too generic, tries to solve too many problems with the same code) What exactly do you mean by FPC defaults ? Michael. ___ fpc-pascal maillist - fpc-pas...@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] OOP and XML usage
but theres a flaw in my model (that doesnot means much in what im doing): the properties in the XML file must match exactly the properties each object has. else the properties are lost.. (the xml file can have less properties than the object but not the other way around: the xml loader cannot force an object to have a published -rtti- property that it doesnt have in code). ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] OOP and XML usage
Example XML, and there isn't a limit to the nesting of options. no theres no limit for nested tags, they are stored in a tree plus a linear list indexed by instance names (nodes without instance names will receive a random instance name - and be basically out of reach by the linear list - but will be still reachable by walking the tree) sorry for so much emails, im in a hurry. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] OOP and XML usage
On Thu, 28 Jan 2010, Jorge Aldo G. de F. Junior wrote: i mean that FPC-XML tries to be too general and this leads to too cumbersome code in various situations (FPC-XML is clearly overkill for my needs). But FPC-XML is not meant for storing objects. It is meant to read any correctly formed XML file that you may find. FPC-XML is not something we invented. It is an implementation of an official W3 specification. (www.w3.org) Having this specification available means that we can read/write any XML document out there that conforms to this spec, in a standard manner. Since the programmer does not always control the XML he/she gets, sticking to the specifications means we're sure we'll we able to handle any XML thrown at us. That is why we implement FCL-XML. Sooner or later the day comes when you'll need it's features, trust me :-) Michael. 2010/1/28 Michael Van Canneyt mich...@freepascal.org: On Thu, 28 Jan 2010, Jorge Aldo G. de F. Junior wrote: im actually needing better RTTI as to allow easier method invocation... But generally i feel my way of doing XML is better than FPC defaults (Too generic, tries to solve too many problems with the same code) What exactly do you mean by FPC defaults ? Michael. ___ fpc-pascal maillist - fpc-pas...@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] OOP and XML usage
Jorge Aldo G. de F. Junior wrote: and actually i prefer to setup properties of objects using xml properties instead of xml text tcpserver ip=192.168.1.1 port=80/ instead of tcpserverip192.168.1.1/ipport80/port/tcpserver Both examples are valid XML, so I don't see any issue the way I am using it. My previous example was just that, an example. My actual XML uses both tag attributes and element text. The later is mainly used for longer text in my xml file. Regards, - Graeme - -- fpGUI Toolkit - a cross-platform GUI toolkit using Free Pascal http://opensoft.homeip.net/fpgui/ ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
[fpc-pascal] OOP and XML usage
Hi, The small project I am working on requires reading a XML file and using that data for various things, including building a GUI interface. Most of my projects are database driven and uses the tiOPF framework to do my load/saving work (plus a lot of other things). As the title says, all my applications are normally object driven. This new project I am working on should not be any different. One big difference though is that it is not database driven and I don't want to bind it to tiOPF framework. So at the moment I reading the xml file and building my own object model based on the various elements and attributes in the XML file. Example: - ?xml version=1.0 standalone=yes? install desc=my description version=0.9 text for install element eula/eula eula lang=afx/eula /install ...would translate to classes as follows: elements become classes and attributes become properties... TSetupFile TInstall TEULAList TEULA Interfaces section of TInstall might look like this TInstall = class(TObject) public property Text: string... // 'text for install element' property Desc: string... // 'my description' property Version: string // '0.9' property EulaList: TEULAList . end; This makes sense to me, and this is the design I am used to following with tiOPF based projects. But like I said, I am not using tiOPF this time and I am working with a XML file, which I haven't worked with before. Am I taking the right OOP approach here, or should I rather be working with the dom unit and TXMLDocument, TXMLElement etc classes directly. At the moment I do not require writing to the XML file, only reading. At a much later date, I'll be writing to the XML file though. I feel my approach of using my own specialized classes is a better fit compared to the generic TXMLElement classes. But I just want to confirm my thoughts and also ask... How do other developers use XML files? Regards, - Graeme - -- fpGUI Toolkit - a cross-platform GUI toolkit using Free Pascal http://opensoft.homeip.net/fpgui/ ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] OOP and XML usage
On Wed, 27 Jan 2010, Graeme Geldenhuys wrote: Hi, The small project I am working on requires reading a XML file and using that data for various things, including building a GUI interface. Most of my projects are database driven and uses the tiOPF framework to do my load/saving work (plus a lot of other things). As the title says, all my applications are normally object driven. This new project I am working on should not be any different. One big difference though is that it is not database driven and I don't want to bind it to tiOPF framework. So at the moment I reading the xml file and building my own object model based on the various elements and attributes in the XML file. Example: - ?xml version=1.0 standalone=yes? install desc=my description version=0.9 text for install element eula/eula eula lang=afx/eula /install ...would translate to classes as follows: elements become classes and attributes become properties... TSetupFile TInstall TEULAList TEULA Interfaces section of TInstall might look like this TInstall = class(TObject) public property Text: string... // 'text for install element' property Desc: string... // 'my description' property Version: string // '0.9' property EulaList: TEULAList . end; This makes sense to me, and this is the design I am used to following with tiOPF based projects. But like I said, I am not using tiOPF this time and I am working with a XML file, which I haven't worked with before. Am I taking the right OOP approach here, or should I rather be working with the dom unit and TXMLDocument, TXMLElement etc classes directly. At the moment I do not require writing to the XML file, only reading. At a much later date, I'll be writing to the XML file though. I feel my approach of using my own specialized classes is a better fit compared to the generic TXMLElement classes. But I just want to confirm my thoughts and also ask... How do other developers use XML files? Yes. I use DOM to read the file, and then translate the found TDOMElement nodes to the actual business classes. Michael. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] OOP and XML usage
Michael Van Canneyt wrote: Yes. I use DOM to read the file, and then translate the found TDOMElement nodes to the actual business classes. Thanks for the quick response. I'm glad I am on the right track and my idea is not totally dumb founded. :) Regards, - Graeme - -- fpGUI Toolkit - a cross-platform GUI toolkit using Free Pascal http://opensoft.homeip.net/fpgui/ ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] OOP and XML usage
I use a similar approach in a systems integration product for a hospital, it
communicates different systems by XML files. The app receives an XML with data
related to an radiology study, then parses the file and convert it to an
object, do some checkings and transformations, and store the object to a
database or reject the message.
Most tags are parsed automatically because them have a one-to-one relation to
the object's properties, and with others we had to create custom associations.
How it works:
1) Create an instance of FCL-XML's TXMLFile class, let's call it lXMLDoc, and
use ReadXMLFile to parse the file.
2) Create a method called, for example ProcessChildNode, as follows:
procedure TMyClass.ProcessChildNode(ANode: TDomNode);
begin
while Assigned(ANode) do
begin
case ANode.NodeType of
ELEMENT_NODE: begin
if ANode.ParentNode.ParentNode nil then
NodeEvent(ANode);
end;
ATTRIBUTE_NODE:;
TEXT_NODE, CDATA_SECTION_NODE: begin
if ANode.ParentNode.ParentNode nil then
NodeEvent(ANode);
end;
end;
if ANode.HasChildNodes then
ProcessChildNode(ANode.FirstChild);
ANode := ANode.NextSibling;
end;
end;
3) Create the NodeEvent method:
procedure TMyClass.NodeEvent(ANode: TDomNode);
begin
case ANode.NodeType of
TEXT_NODE,
CDATA_SECTION_NODE:
{ using RTTI set properties of FMyObject }
SetPropValue(FMyObject, ANode.NodeName, ANode.NodeValue);
// ...
// more types
end;
end;
4) After loading the XML file, let's call ProcessChildNode(lXMLDoc.FirstChild)
this is a recursive method which will traverse all the XML tree, and it will
call the NodeEvent method on only certain types of nodes (look at
ProcessChildNode method). In NodeEvent, the value of the node is set to the
PUBLISHED object's properties by using RTTI, of course, if your XML file
doesn't match one-to-one with your object, you can avoid using RTTI and do the
assignments by hand.
A side note, if your target object, apart from having plain types, it includes
properties of type Object, you can adapt the NodeEvent method, and check for
ANode.ParentNode.NodeName = 'MyInnerObject', then set
FMyObject.MyInnerObject.SomeProperty. That's the way we use to populate an
object from an XML file.
Leonardo M. Ramé
http://leonardorame.blogspot.com
--- On Wed, 1/27/10, Graeme Geldenhuys graemeg.li...@gmail.com wrote:
From: Graeme Geldenhuys graemeg.li...@gmail.com
Subject: [fpc-pascal] OOP and XML usage
To: FPC-Pascal users discussions fpc-pascal@lists.freepascal.org
Date: Wednesday, January 27, 2010, 6:47 AM
Hi,
The small project I am working on requires reading a XML
file and using
that data for various things, including building a GUI
interface.
Most of my projects are database driven and uses the tiOPF
framework to do
my load/saving work (plus a lot of other things).
As the title says, all my applications are normally object
driven. This new
project I am working on should not be any different. One
big difference
though is that it is not database driven and I don't want
to bind it to
tiOPF framework.
So at the moment I reading the xml file and building my own
object model
based on the various elements and attributes in the XML
file.
Example:
-
?xml version=1.0 standalone=yes?
install desc=my description version=0.9
text for install element
eula/eula
eula lang=afx/eula
/install
...would translate to classes as follows: elements become
classes and
attributes become properties...
TSetupFile
TInstall
TEULAList
TEULA
Interfaces section of TInstall might look like this
TInstall = class(TObject)
public
property Text: string...
// 'text for install element'
property Desc: string...
// 'my description'
property Version: string
// '0.9'
property EulaList: TEULAList .
end;
This makes sense to me, and this is the design I am used to
following with
tiOPF based projects. But like I said, I am not using tiOPF
this time and I
am working with a XML file, which I haven't worked with
before.
Am I taking the right OOP approach here, or should I rather
be working with
the dom unit and TXMLDocument, TXMLElement etc classes
directly. At the
moment I do not require writing to the XML file, only
reading. At a much
later date, I'll be writing to the XML file though.
I feel my approach of using my own specialized classes is a
better fit
compared to the generic TXMLElement classes. But I just
want to confirm my
thoughts and also ask...
How do other developers use XML files?
Regards,
- Graeme -
--
fpGUI Toolkit - a cross-platform GUI toolkit using Free
Pascal
http://opensoft.homeip.net/fpgui/
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Re: [fpc-pascal] OOP and XML usage
i dont like this way of working with XML files... im creating my own model using an Class factory and RTTI properties. you register your classes in the class factory and the XML loader uses a class function to select wich one to create for a given node. This lets you have a lot more control over the process. the same objects can save theyselves into another XML file thru a property called AsXML. Class Function XMLTag: String; Virtual; and Function AsXML : String; Virtual; im using this to develop a Component system for Powtils... (But can be used wherever needed) ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] OOP and XML usage
I've written some XML classes which expose themselves as interfaces.
Usage goes something like this:
procedure SaveSettings(const Settings: string);
var
Document: IDocument;
Filer: IFiler;
begin
Document := CreateDocument;
Filer := Document.ForceRoot('test') as IFiler;
Filer.WriteTime('time', Now);
Filer.WriteString('application', Application.ExeName);
Document.SaveToFile(Settings);
end;
testtime21:11:17/timeapplicationtest.exe/application/test
procedure ShowPerson;
var
Document: IDocument;
Root: INode;
begin
Document := CreateDocument;
Filer := Document.ForceRoot('data');
Root.ForceNode('person/age').Value = 17;
Root.FindNode('person[age = 17]').Filer.Write('Jason');
Root.Filer.Write('person/salary', 1);
ShowMessage(Document.Text);
end;
datapersonage17/agenameJason/namesalary1/salary/persondata
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