Encapsulates
the user defined interface to command history.
Synopsis
#include <AlCommand.h>
class AlCommand : public AlObject
AlCommand();
virtual ~AlCommand();
virtual statusCode deleteObject();
virtual AlObjectType type() const;
statusCode create( const char *name );
statusCode install();
statusCode uninstall();
statusCode modified();
int execute( boolean freeIfInvalid = TRUE );
int undo( boolean freeIfInvalid = TRUE );
AlSurfaceType surfaceType() const;
statusCode setSurfaceType( AlSurfaceType );
AlUserCommand* userCommand();
int status() const;
static statusCode setDebug( boolean on );
static statusCode add( AlUserCommandAlloc *, const char *name );
static statusCode remove( const char *name );
Description
This file contains the
definitions required to define an user command history command.
The command layer in Alias is
a software layer that is between the user interface and the main
application. A command is an object that represents actions such as:
fillet, square, or patch.
The user interface code
builds commands that are sent through the layer to be executed. The
user interface does not create geometry itself, it creates commands
that do it.
Commands can be saved
somewhere and re-executed whenever the system feels it is necessary.
As long as the data the command depends upon is valid, the command
remains valid.
The most practical application
of re-executing a command is the generation of data from a piece
of source geometry. When the original geometry changes, the new
model can be ’automatically’ created by re-executing the command
history on the new data.
Command functions: These
are outlined in the AlUserCommand class.
A ‘constructor’ DAG node
is considered to be a DAG node which creates the result. An example
of a constructor is one of the original curves in a fillet operation.
A ‘target’ DAG node is
considered to be the result of a command operation. An example is
the fillet created by the fillet command.
The ’AlCommand’ class
is used to maintain a list of the current plug-in defined command history
commands. New commands are installed using the ’AlCommand::add’
method. This associates a string with a function that allocates
a new copy of a command. The first parameter of the add command
is a AlUserCommandAlloc. An AlUserCommandAlloc is a pointer to
a function returning an AlUserCommand class as defined below.
typedef AlUserCommand *AlUserCommandAlloc();
AlCommand::remove is
used to remove a command type from the database.
AlCommand::create is
used to create an new copy of the command. After a command has been
created, its data fields can be accessed using the ’AlCommand->userCommand’ method.
A command has two components,
the UI driver and the underlying geometry manipulation code. The
UI creates a new command using AlCommand::create. The private data
is accessed using the AlCommand -> userCommand method (which
is typecast to the plug-in’s derived command). From this, the command
data structure’s fields can be filled in. The UI uses the execute
method to call the userCommand’s execute command. This does the
actual command. Finally the result is added to the Alias system using
the ’install’ method.
The Alias messaging
system will call the various functions in the command to maintain
the dependencies and re-execute the command if necessary.
statusCode AlCommand::setDebug(
boolean on )
Description
Turns command history debugging on (TRUE) or off (FALSE). Alias will
write information into the errlog as the construction history plug-in
runs if this boolean is set.
Arguments
< on - the new value
of command history debugging
Return Codes
sSuccess - setting worked
AlCommand::AlCommand()
Description
Constructor for a command wrapper.
AlCommand::~AlCommand()
Description
Destructor for a command wrapper.
AlObjectType AlCommand::type()
const
Description
Returns
kCommandType.
AlCommand *AlCommand::asCommandPtr()
Description
Safe
downcast to AlCommand.
AlUserCommand *AlCommand::userCommand()
Description
Returns
a pointer to the user command.
int AlCommand::status()
const
Description
Returns
the value of the result from the last execution of the command.
Returns -1 if this command is invalid.
statusCode AlCommand::create(
const char *name )
Description
Allocates a new user defined
command history command.
Arguments
< name - the name
of the command to create
Return Codes
sSuccess - method was
successful
sInvalidArgument - name
was NULL
sObjectNotFound - the
command name was not found (undefined)
sFailure - not enough
memory or user constructor failure
statusCode AlCommand::deleteObject()
Description
Deletes
the command (also calls the user command destructor)
Return Codes
sSuccess - the command
was deleted
sInvalidObject - the
command was invalid
AlSurfaceType AlCommand::surfaceType()
const
Description
Gets
the type of surface produced by the given command.
statusCode AlCommand::modified()
Description
Marks
this command as being modified.
Return Codes
sInvalidObject - the
command was invalid
sSuccess - the command
was marked as being modified
statusCode AlCommand::setSurfaceType(
AlSurfaceType type )
Description
Sets the type of
surface produced by the given command.
Arguments
< type - type of surface
to be produced by the given command
Return Codes
sSuccess - setting was
successful
sInvalidArgument - type
was neither kSurfaceSpline nor kSurfacePolyset
sInvalidObject - the
command was invalid
statusCode AlCommand::install()
Description
Installs
a command in the construction history list.
Return Codes
sInvalidObject - the
command was invalid
sSuccess - the command
was installed
sFailure - the command
was already installed
statusCode AlCommand::uninstall()
Description
Remove
a command from the construction history list.
Return Codes
sInvalidObject - the
command was invalid
sSuccess - the command
was uninstalled
sFailure - the command
was not installed
int AlCommand::execute(
boolean freeIfInvalid )
Description
Executes the command after it
has been created. Do not directly call the execute command in the
user command, but use this function instead.
Arguments
< freeIfInvalid -
the command is freed if it is found to be invalid
Return Values
zero - command was successful
negative number - the
command is no longer valid
positive number - the
command did not succeed (the number returned is the error return value)
int AlCommand::undo( boolean
freeIfInvalid )
Description
Undoes the command after it has been created. Do not
directly call the undo command in the user command, but use this
function instead.
Arguments
< freeIfInvalid -
the command is freed if it is found to be invalid
Return Values
zero - command was successful
negative number - the
command is no longer valid
positive number - the
command did not succeed (the number returned is the error return value)
statusCode AlCommand::add(
AlUserCommandAlloc *func, const char *name )
Description
Adds
the construction history command to the list of available commands.
Arguments
func - name of the function
that will allocate the new AlUserCommand
name - string name of
the function
Return Codes
sFailure - another command
with the same name already exists
sInvalidArgument - func
is NULL or name is NULL
sInsufficientMemory -
could not allocate memory for new function
sSuccess - the add was
successful
statusCode AlCommand::remove(
const char *name )
Description
Deletes the construction
history command.
Arguments
name - string name of
the function
Return Codes
sFailure - command not
found
sInvalidArgument - name
is NULL
sSuccess - command was
removed
