TWriter

[Properties (by Name)][Methods (by Name)][Events (by Name)]

Object to write component data to an arbitrary format.

Declaration

Source position: classesh.inc line 1701

Type
  TWriter = class (TFiler)
  private
    FDriver : TAbstractObjectWriter;
    FDestroyDriver : Boolean;
    FRootAncestor : TComponent;
    FPropPath : string;
    FAncestors : TStringList;
    FAncestorPos : Integer;
    FCurrentPos : Integer;
    FOnFindAncestor : TFindAncestorEvent;
    FOnWriteMethodProperty : TWriteMethodPropertyEvent;
    FOnWriteStringProperty : TReadWriteStringPropertyEvent;
    procedure AddToAncestorList(Component: TComponent);
    procedure WriteComponentData(Instance: TComponent);
    procedure DetermineAncestor(Component: TComponent);
    procedure DoFindAncestor(Component: TComponent);
  protected
    procedure SetRoot(ARoot: TComponent);  Override;
    procedure WriteBinary(AWriteData: TStreamProc);
    procedure WriteProperty(Instance: TPersistent; PropInfo: Pointer);
    procedure WriteProperties(Instance: TPersistent);
    procedure WriteChildren(Component: TComponent);
    function CreateDriver(Stream: TStream; BufSize: Integer)
                          : TAbstractObjectWriter;  Virtual;
  public
    constructor Create(ADriver: TAbstractObjectWriter);
    constructor Create(Stream: TStream; BufSize: Integer);
    destructor Destroy;  Override;
    procedure FlushBuffer;  Override;
    procedure DefineProperty(const Name: string; ReadData: TReaderProc; 
                            AWriteData: TWriterProc; HasData: Boolean)
                            ;  Override;
    procedure DefineBinaryProperty(const Name: string; 
                                  ReadData: TStreamProc; 
                                  AWriteData: TStreamProc; HasData: Boolean)
                                  ;  Override;
    procedure Write(const Buffer; Count: LongInt);  Virtual;
    procedure WriteBoolean(Value: Boolean);
    procedure WriteCollection(Value: TCollection);
    procedure WriteComponent(Component: TComponent);
    procedure WriteChar(Value: Char);
    procedure WriteWideChar(Value: WideChar);
    procedure WriteDescendent(ARoot: TComponent; AAncestor: TComponent);
    procedure WriteFloat(const Value: Extended);
    procedure WriteSingle(const Value: Single);
    procedure WriteDate(const Value: TDateTime);
    procedure WriteCurrency(const Value: Currency);
    procedure WriteIdent(const Ident: string);
    procedure WriteInteger(Value: LongInt);  Overload;
    procedure WriteInteger(Value: Int64);  Overload;
    procedure WriteSet(Value: LongInt; SetType: Pointer);
    procedure WriteListBegin;
    procedure WriteListEnd;
    procedure WriteSignature;
    procedure WriteRootComponent(ARoot: TComponent);
    procedure WriteString(const Value: string);
    procedure WriteWideString(const Value: WideString);
    procedure WriteUnicodeString(const Value: UnicodeString);
    procedure WriteVariant(const VarValue: Variant);
    RootAncestor : TComponent;
    OnFindAncestor : TFindAncestorEvent;
    OnWriteMethodProperty : TWriteMethodPropertyEvent;
    OnWriteStringProperty : TReadWriteStringPropertyEvent;
    Driver : TAbstractObjectWriter;
    PropertyPath : string;
  end
  ;

Description

The TWriter class is a writer class that implements generic component streaming capabilities, independent of the format of the data in the stream. It uses a driver class TAbstractObjectWriter to do the actual reading of data. The interface of the TWriter class should be identical to the interface in Delphi.

Note that the TWriter design is such that it will write a single component to a stream. It will write all children of this component, but it is not designed to write multiple components in succession to one stream.

It should never be necessary to create an instance of this class directly. Instead, the TStream.WriteComponent call should be used.

Members

Member	Type	Visibility	Description
AddToAncestorList	Method	private
Create	Method	public	Creates a new Writer with a stream and bufsize.
CreateDriver	Method	protected
DefineBinaryProperty	Method	public	Callback used when defining and streaming custom properties.
DefineProperty	Method	public	Callback used when defining and streaming custom properties.
Destroy	Method	public	Destroys the writer instance.
DetermineAncestor	Method	private
DoFindAncestor	Method	private
Driver	Property	public	Driver used when writing to the stream.
FAncestorPos	Field	private
FAncestors	Field	private
FCurrentPos	Field	private
FDestroyDriver	Field	private
FDriver	Field	private
FlushBuffer	Method	public	Flush the buffer
FOnFindAncestor	Field	private
FOnWriteMethodProperty	Field	private
FOnWriteStringProperty	Field	private
FPropPath	Field	private
FRootAncestor	Field	private
OnFindAncestor	Property	public	Event occurring when an ancestor component must be found.
OnWriteMethodProperty	Property	public	Handler from writing method properties.
OnWriteStringProperty	Property	public	Event handler for translating strings written to stream.
PropertyPath	Property	public	Path to the property that is currently being written
RootAncestor	Property	public	Ancestor of root component.
SetRoot	Method	protected	Sets the root component
Write	Method	public	Write raw data to stream
WriteBinary	Method	protected	Writes binary data to the stream.
WriteBoolean	Method	public	Write boolean value to the stream.
WriteChar	Method	public	Write a character to the stream.
WriteChildren	Method	protected
WriteCollection	Method	public	Write a collection to the stream.
WriteComponent	Method	public	Stream a component to the stream.
WriteComponentData	Method	private
WriteCurrency	Method	public	Write a currency value to the stream
WriteDate	Method	public	Write a date to the stream.
WriteDescendent	Method	public	Write descendent to stream
WriteFloat	Method	public	Write a float to the stream.
WriteIdent	Method	public	Write an identifier to the stream.
WriteInteger	Method	public	Write an integer to the stream.
WriteListBegin	Method	public	Write a start-of-list marker to the stream.
WriteListEnd	Method	public	Write an end-of-list marker to the stream.
WriteProperties	Method	protected	Writes the published properties to the stream.
WriteProperty	Method	protected	Writes one property to the stream.
WriteRootComponent	Method	public	Write a root component to the stream.
WriteSet	Method	public	Write a set value to the stream
WriteSignature	Method	public	Write a signature to the stream
WriteSingle	Method	public	Write a single-type real to the stream.
WriteString	Method	public	Write a string to the stream.
WriteUnicodeString	Method	public	Write a Unicode string to the stream.
WriteVariant	Method	public	Write a variant to the stream
WriteWideChar	Method	public	Write widechar to stream
WriteWideString	Method	public	Write a widestring value to the stream

Inheritance

Class	Description
TWriter	Object to write component data to an arbitrary format.

TWriter

Declaration

Description

Members

Inheritance

See also

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Name	Description
Integer	A signed 16-bits integer
Integer	A signed 16-bits integer
TAbstractObjectReader	Abstract driver class to read stored component data.
TAbstractObjectWriter	Abstract driver class for writing component data.
TAbstractObjectWriter	Abstract driver class for writing component data.
TComponent	Base class for all components that need owner-owned functionality.
TComponent	Base class for all components that need owner-owned functionality.
TFiler	Class responsible for streaming of components.
TFindAncestorEvent	Event that occurs w
TFindAncestorEvent	Event that occurs w
TReadWriteStringPropertyEvent	Callback for the TReader.OnReadStringProperty event handler
TReadWriteStringPropertyEvent	Callback for the TReader.OnReadStringProperty event handler
TStringList	Standard implementation of the TStrings class.
TWriteMethodPropertyEvent	Callback for the TWriter.OnWriteMethodProperty event.
TWriteMethodPropertyEvent	Callback for the TWriter.OnWriteMethodProperty event.
TWriter	Object to write component data to an arbitrary format.