Like most of the tool’s dialogs, the concealed variable dialog is organized into three sections: input fields, action buttons, and a display.. In Figure 17.7, the input fields contain va
Trang 117.2.1.4 Concealed Variables … Dialog
Clicking the Concealed Variables … button brings up the dialog shown in Figure 17.7 The dialog shown in the figure contains an entry for one variable Like most of the tool’s dialogs, the concealed variable dialog is organized into three sections: input fields, action buttons, and a display In Figure 17.7, the input fields contain values because a variable name in the display is selected Selecting a blank line will empty all values in the input fields Even the name field will
be empty because there is no suggested naming convention Any legal variable name except
mDisplayFunc can be entered in the field The variable name mDisplayFunc is reserved for
Class Wizard’s use, and Class Wizard will include it in class code when necessary
The five data-entry fields in the concealed variable dialog are described by the following:
Concealed Variable Name: holds the name of a concealed member variable.
Concealed variables are added one at a time
Type: holds a string that describes the variable’s type In response to get(obj) or set(obj), concealed variables are not displayed; however, the type string is included
in the header comments of several files, get and set for example
Accessor Expression: holds the expression used for accessing the variable The
contents of this field are limited to two special cases: the exact name of a private member variable or the keyword %helper When the name of a private member variable is used, direct-link accessor code is included in get.m This option also allows clients to specify additional indices beyond the first dot-reference The %helper keyword causes
FIGURE 17.7 Class Wizard, Concealed Variables … dialog.
Trang 2helper-function syntax (non-direct-link) to be used inside get.m The %helper keyword also triggers the generation of a helper-function stub The stub contains a complete header along with some initial code and comments Accessing a concealed variable with a default helper will not cause an error, but the return value will be empty until the helper is customized
Mutator Expression: holds the expression used for assigning values into the variable.
Like the accessor, the contents of this field are limited to two special cases: the exact name
of a private member variable or the keyword %helper When the name of a private member variable is used, direct-link mutator code is included in set.m This option also allows clients to specify additional indices beyond the first dot-reference The %helper keyword causes helper-function syntax to be used inside set.m The %helper keyword also triggers the generation of a helper-function stub The stub contains a complete header along with some initial code and comments Mutating a concealed variable with a default helper will not cause an error, but values in the object will not be modified until the helper
is customized
Comment: holds a text description of the variable The text description is important because
it will show up along with the variable name and variable type in various header comments, where it will serve as a reference to other developers
In this case, the display list box does not provide a what-you-see-is-what-you-get (WYSIWYG) format WYSIWYG is not possible because each name links to multiple files in the group-of-eight and each file uses the name differently Instead of WYSIWYG, the display box shows individual fields separated by double colons This achieves the goal of providing a good one-line overview without the complications involved in writing the exact syntax
The three buttons, Save Change, Delete, and Done, are the same three buttons used in the parent-class dialog Refer to §17.2.1.2 for a description of their behavior When you finish modifying the object’s concealed data, click the Done button This will save your changes and return you to the main dialog Concealed-variable names are shown in the list box adjacent to the
Concealed Variables … button The names provide a quick summary, and in the main
dialog view they are not active You have to open the concealed variable dialog to make changes
or see more detail
17.2.1.5 Public Variables … Dialog
Clicking the Public Variables … button brings up the dialog shown in Figure 17.8 The dialog shown in the figure contains an entry for one variable Like most of the tool’s dialogs, the public variable dialog is organized into three sections: input fields, action buttons, and a display
In Figure 17.8, the input fields contain values because a variable name in the display is selected Selecting a blank line will empty all values in the input fields Even the name field will be empty because there is no suggested naming convention Any legal variable name can be entered in the name field
The fields in this dialog are identical to those for concealed variables because in reality the only difference is the simplified syntax used to access public variables Public variables can be accessed or mutated using the dot-reference operator via subsref and subsasgn, while access
to concealed-variables is limited to get and set In the code, public variables are written into the public section of get and set while concealed variables are written into the concealed section Beyond that, there is little difference between public and concealed The five data-entry fields in the public variable dialog are as follows:
Trang 3Public Variable Name: holds the name of a public member variable Public variables
are added one at a time
Type: holds a string that describes the variable’s type This string is displayed along with
the variable name when get(obj) or set(obj) is used to display member variable hints The type string also shows up in the header comments of various files, get and set for example.
Accessor Expression: holds the expression used for accessing the variable The
contents of this field are limited to two special cases: the exact name of a private member variable or the keyword %helper When the name of a private member variable is used, direct-link accessor code is used inside get.m This option also allows clients to specify additional indices beyond the first dot-reference The %helper keyword causes helper-function syntax (non-direct-link) to be used inside get.m The %helper keyword also triggers the generation of a helper-function stub The stub contains a complete header along with some initial code and comments Accessing a public variable with a default helper will not cause an error, but the return value will be empty until the helper is customized
Mutator Expression: holds the expression used for assigning values into the variable.
Like the accessor, the contents of this field are limited to two special cases: the exact name
of a private member variable or the keyword %helper When the name of a private member variable is used, direct-link mutator code is used inside set.m This option also allows clients to specify additional indices beyond the first dot-reference The %helper keyword causes helper-function syntax to be used inside set.m The %helper keyword also triggers the generation of a helper-function stub The stub contains a complete header
FIGURE 17.8 Class Wizard, Public Variables … dialog.
Trang 4along with some initial code and comments Mutating a public variable with a default helper will not cause an error, but values in the object will not be modified until the helper
is customized
Comment: holds a text description of the variable The text description is important because
it will show up along with the variable name and variable type in various header comments, where it will serve as a reference to other developers
In this case, the display list box does not provide a what-you-see-is-what-you-get (WYSIWYG) format WYSIWYG is not possible because each name links to multiple files in the group of eight and each file uses the name differently Instead of WYSIWYG, the display box shows individual fields separated by double colons This achieves the goal of providing a good one-line overview without the complications involved in writing the exact syntax
The three buttons, Save Change, Delete, and Done, are the same three buttons used in the parent-class dialog Refer to §17.2.1.2 for a description of their behavior When you finish modifying the object’s public data, click the Done button This will save your changes and return you to the main dialog Public variable names are shown in the list box adjacent to the Public
Variables … button The names provide a quick summary, and in the main dialog view they
are not active You have to open the public variable dialog to make changes or see more detail
17.2.1.6 Constructors … Dialog
Clicking the Constructors … button brings up the dialog shown in Figure 17.9 The dialog shown in the figure contains an entry for one constructor in addition to the default Like most of the tool’s dialogs, the constructor dialog is organized into three sections: input fields, action buttons, and a display In Figure 17.9, the lone input field contains a value because a constructor name in the display is selected Selecting a blank line will empty this field
FIGURE 17.9 Class Wizard, Constructors … dialog.
Trang 5In the selected case, the constructor-helper function will be named ctor_1 because there is one input argument This is consistent with the constructor-helper naming convention previously discussed Inputs are specified using the comma-separated list, and Class Wizard generates a stub for the helper
The single data-entry field in the constructor dialog is described by the following:
Input Argument List: holds a comma-separated list of input arguments for each
constructor-helper function The variable name this should never be included in the input argument list When files are generated, helper-function names are set according to the number of variables in each comma-separated list The function prototype for each helper includes this along with the names in the comma-separated list Functional stubs for each constructor helper are written into the class’ private directory The default stub does not know how to use the input arguments, so you must tailor each helper according
to the specific application Variables from each comma-separated list are added to the data dictionary Comments can be associated with each dictionary name using the main dialog’s
Data menu item
The display list box provides a WYSIWYG format for the function definition of each helper In this case displayed in Figure 17.9, the function name is ctor_1 because the constructor is meant for the case when an object is constructed from one input The function prototype for ctor_1 actually contains two inputs: this and the variable from the Input Argument List field The object itself is passed in and out of the constructor because the whole purpose is to populate the object with values other than default The constructor helper can modify the value’s existing private variables but cannot add new fields This helps protect the integrity of the objects The three buttons, Save Change, Delete, and Done, are the same three buttons used in the parent-class dialog Refer to §17.2.1.2 for a description of their behavior When you finish modifying the object’s public data, click the Done button This will save your changes and return you to the main dialog Helper names are shown in the list box adjacent to the Constructors
… button The names provide a quick summary, and in the main dialog view they are not active.
You have to open the constructor dialog to make changes or see more detail
17.2.1.7 More … Dialog
Clicking the More … button brings up the dialog shown in Figure 17.10 This dialog provides access to a group of data-entry dialogs for additional class features Most of these features involve Part 3 topics; however, Private Functions … and Public Functions … are immediately useful With these buttons, you can enter data for class-specific public and private functions Dialogs are activated by respectively clicking the buttons Public Functions … and
Private Functions … Unlike functions in the group of eight, Class Wizard does not know
how to configure code for general public and private functions Instead, Class Wizard resorts to the same strategy used for helper functions and generates a function stub The function stub will contain
a consistently formatted function call and a header that includes detailed function comments These comments draw from the data dictionary to include information for input–output variables As a result, the generated member functions usually have more detailed comments compared to those that are not automatically generated The stub also includes enough code to allow the function to execute, albeit at a greatly reduced level of function
The other buttons in the dialog represent class features that are less common but no less useful under the right circumstances At first, the number of buttons is daunting; however, the layouts of the underlying dialogs are very similar if not identical to those we have already discussed Entering data follows the same procedure The data end up in slightly different locations You already know the most important locations, and the next section discusses a few more elements
Trang 617.2.1.8 Static Variables … Dialog
Clicking the Static Variables … button brings up the dialog shown in Figure 17.11 The dialog shown in the figure contains an entry for one variable Like most of the tool’s dialogs, the static variable dialog is organized into three sections: input fields, action buttons, and a display In Figure 17.11 the input fields contain values because a variable name in the display is selected Selecting a blank line will insert an m in Static Variable Name, and the other fields will
be blank A leading m shows up by default because a static variable is a special kind of private variable The difference between static and private is scope With a private variable, every object gets its own copy; but with a static variable, every object of the class shares one copy If one object sets the value, that value shows up in all objects of the class
When static variables are defined, the private helper function static.m is used to manage them The interface to static.m is very similar to the interface defined for accessor–mutator helpers The details are described in Chapter 20
The three data-entry fields in the static variable dialog are described by the following:
Static Variable Name: holds the name of a static member variable Static variables are added one at a time
Initial Value: holds the default value that will be assigned to the variable by the constructor The field value is entered using the exact syntax required in the assignment The display list box formats the input exactly as it will be written into ctor_ini.m.
What you see in the display list box is exactly what you get in ctor_ini.m Virtually any legal syntax can be used
Comment: holds a text description of the variable The text description is important because
it will show up in the header of ctor_ini.m, where it will serve as a future reference for developers
The three buttons, Save Change, Delete, and Done, are the same three buttons used in the parent-class dialog Refer to §17.2.1.2 for a description of their behavior When you finish modifying the object’s parent data, click the Done button This will save your changes and return you to the more dialog Static member variable names are shown in the list box adjacent to the
Static Variables … button The names provide a quick summary, and in the more dialog
FIGURE 17.10 Class Wizard, More … dialog.
Trang 7view they are not active You have to open the static variable dialog to make changes or see more detail
17.2.1.9 Private Functions … Dialog
Clicking the Private Functions … button brings up the dialog shown in Figure 17.12 The dialog shown in the figure contains an entry for one function Like most of the tool’s dialogs, the private-function dialog is organized into three sections: input fields, action buttons, and a display
In Figure 17.12, the input fields contain values because a function name in the display is selected Selecting a blank line will empty all values in the input fields Even the name field will be empty because there is no suggested naming convention Any legal function name can be entered in the name field
In reality, constructor helpers, accessor–mutator helpers, and parent_list.m are private functions; however, these are part of the group-of-eight interface and are managed separately from class-specific private functions Only class-specific private functions show up in this list
Private functions, like most functions, can be described by a function name, a list of input arguments, a list of output arguments, and a comment The data-entry fields for these four function elements are described by the following:
Function Name: holds the desired name for the function Any valid function name can
be used
Input Argument List: holds a comma-separated list of input arguments for the function If a copy of the object must be passed, this must be included in the argument list By convention, when it exists, this should usually be the first argument in the list
In addition, notice there is no way to enter comments for individual arguments Instead, variable names are added to the data dictionary using the Data menu on the main screen
FIGURE 17.11 Class Wizard, Static Variables … dialog.
Trang 8Output Argument List: holds a comma-separated list of output arguments for the
function If a copy of the object is passed, this must be included in the argument list
By convention, when it exists, this should usually be the first argument in the argument list As with variables in the input argument list, output variable names are added to the data dictionary
Comment: holds a text description of the function The text description will be added to
the header comments when the function is generated
Clicking the Save Change button commits the changes and displays the function prototype in WYSIWYG format During file generation, Class Wizard writes the same function prototype into the private function and follows the prototype with header comments Of course, Class Wizard doesn’t know how to write the real function body, but it can write a body that runs without error The body of the private function must be manually modified to include the desired class-specific functionality
The three buttons, Save Change, Delete, and Done, are the same three buttons used in the parent-class dialog Refer to §17.2.1.2 for a description of their behavior When you finish modifying the object’s private-function data, click the Done button This will save your changes and return you to the more dialog Private-function names are shown in the list box adjacent to the
Private Functions … button The names provide a quick summary, and in the more dialog
view they are not active You have to open the private-function dialog to make changes or see more detail
FIGURE 17.12 Class Wizard, Private Function … dialog.
Trang 917.2.1.10 Public Functions … Dialog
Clicking the Public Functions … button brings up the dialog shown in Figure 17.13 The dialog shown in the figure contains an entry for one function Like most of the tool’s dialogs, the public-function dialog is organized into three sections: input fields, action buttons, and a display
In Figure 17.13, the input fields contain values because a function name in the display is selected Selecting a blank line will empty all values in the input fields Even the name field will be empty because there is no suggested naming convention Any legal function name can be entered in the name field
In reality, standard group-of-eight functions are public functions; however, group-of-eight functions are managed separately from class-specific public functions Only class-specific public functions show up in this list
Public functions, like most functions, can be described by a function name, a list of input arguments, a list of output arguments, and a comment The data-entry fields for these four function elements are described by the following:
Function Name: holds the desired name for the function Any valid function name can
be used
Input Argument List: holds a comma-separated list of input arguments for the
function If a copy of the object must be passed, this must be included in the argument
FIGURE 17.13 Class Wizard, Public Function … dialog.
Trang 10list By convention, when it exists, this should usually be the first argument in the list.
In addition, notice there is no way to enter comments for individual arguments Instead, variable names are added to the data dictionary using the Data menu on the main screen
Output Argument List: holds a comma-separated list of output arguments for the
function If a copy of the object is passed, this must be included in the argument list
By convention, when it exists, this should usually be the first argument in the argument list As with variables in the input argument list, output variable names are added to the data dictionary
Comment: holds a text description of the function The text description will be added to
the header comments when the function is generated
Clicking the Save Change button commits the changes and displays the function prototype in WYSIWYG format During file generation, Class Wizard writes the same function prototype into the private function and follows the prototype with header comments Of course, Class Wizard doesn’t know how to write the real function body, but it can write a body that runs without error The body of the private function must be manually modified to include the desired class-specific functionality
The three buttons, Save Change, Delete, and Done, are the same three buttons used in the parent-class dialog Refer to §17.2.1.2 for a description of their behavior When you finish modifying the object’s public-function data, click the Done button This will save your changes and return you to the more dialog Public-function names are shown in the list box adjacent to the
Public Functions … button The names provide a quick summary, and in the more dialog
view they are not active You have to open the public-function dialog to make changes or see more detail
17.2.1.11 File Menu
The main Class Wizard dialog has two menu items: File and Data The File menu allows you
to create a New class definition, Open … an existing definition, Save the current definition, or
Save as … to save the current definition using a different file name These menu items behave
the same as any application that opens and saves files Their behaviors are described as follows:
File::New: Select this item to begin a new class definition The hot-key sequence is ctrl-N All fields are reset to default initial values, usually empty Currently, using File::New does not check for changes to the currently loaded values before loading a
new file You will not be warned to save your changes
File::Open : Selecting this item allows you to open an existing file using the
standard file-open dialog box The hot-key combination is ctrl-O This familiar dialog
is shown in Figure 17.14 The file format for definition files is mat This format is convenient because it allows you to load the definition file directly in MATLAB and tweak the data in ways not available through Class Wizard
File::Save: Selecting this item saves the current class definition file to the current file
name The hot-key sequence is ctrl-S If there is no current filename, you will be prompted to enter one
File::Save As : Selecting this item opens a standard dialog box for specifying
the file name during a save The hot-key sequence is ctrl-A The familiar dialog is shown
in Figure 17.15 The definition file can be stored anywhere; however, the best location is
in the class directory When class functions are generated, the definition file is automatically saved in the same directory as the functions