file

Class FileSpace

java.lang.Object

file.FileSpace

abstract class FileSpace
extends java.lang.Object

A FileSpace is an abstract model of a file space in the operating environment in which the CalendarTool is run. The FileSpace is simply a collection of zero or more Files, with no other properties modeled here. All of the FileSpace methods operate parametrically with and on a UserWorkSpace. Callers send in a workspace and capture the modified return value as appropriate to the calling context. The expectation is that the caller is responding to a user request to perform an operation on the currently active workspace in which the user is operating.

Field Summary

Fields

Modifier and Type	Field and Description
(package private) java.util.Collection<File>	files As noted in the class-level comment, a the highly-abstract data represenation of a file space is simply a collection of files.

Constructor Summary

Constructors

Constructor and Description
FileSpace()

Method Summary

Methods

Modifier and Type	Method and Description
(package private) abstract void	close(FileSpace fs, UserWorkSpace uws) Close the current calendar if it does not require saving.
(package private) abstract UserWorkSpace	fileNew(UserWorkSpace uws) Add a new empty calendar to the given workspace and make it current.
(package private) abstract boolean	isUniqueName(UserWorkSpace uws, UserCalendar uc) If the name of the given user calendar is not unique in the given workspace uws, then suffix it with a unique integer.
(package private) abstract void	open(FileSpace fs, java.lang.String fn, UserWorkSpace uws) Open an existing calendar file of the given name and put the data from that file in the workspace.
(package private) abstract void	save(FileSpace fs, UserWorkSpace uws) If the calendar in the given workspace requires saving, save it in the given file space.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

files

java.util.Collection<File> files

As noted in the class-level comment, a the highly-abstract data represenation of a file space is simply a collection of files.

Constructor Detail

FileSpace

FileSpace()

Method Detail

fileNew

abstract UserWorkSpace fileNew(UserWorkSpace uws)

Add a new empty calendar to the given workspace and make it current. Return the result.

      post:
        // The output workspace has a new empty calendar and that calendar is
        // current.  The settings and user id of the new calendar are those of
        // the workspace.  The file is empty.  The name is unique, per the
        // logic defined in isUniqueName, which requires a unique numeric
        // suffix if necessary for disambiguation.  The selected calendar date
        // is today and the calendar does not require saving.  The calendars in
        // positions 1-last in the the input workspace are in positions
        // 2-last+1 in the output workspace.  All other calendars in the input
        // workspace are in the output workspace, and nothing else is.
        exists (UserCalendar uc ;
            (uc.items == null) &&
            (return.calendars.get(0) == uc) &&
            (uc.settings.equals(uws.settings.cal)) &&
            (uc.uid.equals(uws.uid)) &&
            (uc.file == null) &&
            isUniqueName(uws, return, uc) &&
            (uc.selected_date).equals(today()) &&
            (! uc.requires_saving) &&
            forall (int i ; (i >= 1) && (i <= uws.calendars.size()) ;
                return.calendars.get(i+1).equals(uws.calendars.get(i))) &&
            forall (UserCalendar uc_other ;
                return.calendars.contains(uc_other) &&
                    uc_other.equals(uc) || uws.calendars.contains(uc)));

open

abstract void open(FileSpace fs,
        java.lang.String fn,
        UserWorkSpace uws)

Open an existing calendar file of the given name and put the data from that file in the workspace.

      pre:
        //
        // A file of the given name exists in the given file space, the file
        // is readable, and the file's data are of type calendar.
        //
        exists (File file ; fs.contains(file) ;
            (file.name.equals(fn)) &&
            file.permissions.is_readable &&
            file.file_type == CALENDAR_TYPE);

    post:
        //
        // The output workspace has a new calendar containing the file data of
        // the input file, and that calendar is current.  The user id of the
        // new calendar is that of the workspace, the options are the given
        // global options input, and the calendar does not require saving.  The
        // calendars in positions 1-last in the the input workspace are in
        // positions 2-last+1 in the output workspace.
        //
        exists (uc:UserCalendar ;
            (uc.equals(uws'.calendars.get(0))) &&
            (exists (File file; fs.contains(file) ;
                (file.name.equals(fn)) &&
                (uc.equals(file.data))
            ) &&
            (uc.uid.equals(uws.uid)) &&
            isUniqueName(uws, uws', uc) &&
            (uc.selected_date).equals(today()) &&
            (not uc.requires_saving) &&
            (uws'.calendars.size().equals(uws.calendars.size() + 1)) &&
            (forall (int i ; (i >= 2) && (i <= #(uws.calendars)))
                uws'.calendars.get(i+1).equals(uws.calendars.get(i+1))
            )
        );

close

abstract void close(FileSpace fs,
         UserWorkSpace uws)

Close the current calendar if it does not require saving.

      pre: 
        //
        // The calendar does not require saving.
        //
        ! (uws.calendars.get(0).requires_saving);

      post:
        //
        // The current calendar is deleted from the workspace.  The remaining
        // calendars, if any, are shifted in position in the list one position
        // earlier.
         //
        (! (uws'.calendars.contains(uws.calendars.get(0)) &&
        (uws'.calendars.sizd().equals(uws.calendars.size() - 1)) &&
        forall (int i ; (i >= 1) && (i < #(uws.calendars)))
            uws'.calendars.get(i) == uws.calendars.get(i+1);
        );

save

abstract void save(FileSpace fs,
        UserWorkSpace uws)

If the calendar in the given workspace requires saving, save it in the given file space.

      pre:
        //
        // The given workspace requires saving.  Also, there is a writable
        // file of the current workspace filename in the given FileSpace.  Note
        // that the only way the current file could be unwritable is through an
        // external change to the file space since the file was opened by the
        // Calendar Tool.  Note further that this precondition disallows the
        // case where the current calendar file has been externally deleted
        // since it was opened by the calendar tool.  That is, the file must
        // both exist and be writable at the time the save is attempted.
        //
        (uws.calendars.get(0).requires_saving)

            &&

        exists (file File; fs.contains(file) ;
            (file.name.equals(uws.calendars.get(0).file.name)) &&
            (file.permissions.is_writable));

      post:
        //
        // There is a calendar-type file in the resulting FileSpace containing
        // the current workspace calendar as its file data.  In the resulting
        // workspace, the requires saving indicator is false.
        //
        exists (File file; fs'.contains(file) ;
            (file.name.equals(uws'.calendars.get(0).file.name)) &&
            (file.data.equals(uws'.calendars.get(0))) &&
            (file.permissions.is_writable) &&
            (file.file_type == CALENDAR_TYPE) &&
            (not uws'.calendars.get(0).requires_saving)
        );

isUniqueName

abstract boolean isUniqueName(UserWorkSpace uws,
                   UserCalendar uc)

If the name of the given user calendar is not unique in the given workspace uws, then suffix it with a unique integer. The integer is one greater than the suffix of same-name calendar with the largest suffix in uws. If name of the given calendar is unique in uws, then its name suffix is null. post: // Left as exercise for the reader