Programming Python (Mark Lutz / 4th Edition / O'Reilly) – Examples

person.py

#!/usr/local/bin/python3

"""
Implementation of persons for a pim database
"""

import shelve
import tkinter
import tkinter.messagebox


DEFAULT_SHELVE_NAME = 'people'


class Person:
    """
    gerneral Person class
    """

    def __init__(self, name, age, pay=0, job=None):
        self.name = name
        self.age = age
        self.pay = pay
        self.job = job

    def __str__(self):
        properties = []
        for prop in self.__dict__:
            properties.append('%s: %s' % (prop, self.__dict__[prop]))
        return ('<%s => %s>' %
                (self.__class__.__name__, '; '.join(properties)))

    def last_name(self):
        return name.split()[-1]

    def give_raise(self, percent):
        self.pay *= (1.0 + percent)

    def key(self):
        return self.name.replace(' ', '_')

    def save_to(self, shelve_name):
        db = shelve.open(shelve_name)
        db[self.key()] = self
        db.close()

    def save(self):
        self.save_to(DEFAULT_SHELVE_NAME)

    @classmethod
    def load_from(cls, shelve_name, key):
        db = shelve.open(shelve_name)
        result = db[key]
        db.close()
        return result

    @classmethod
    def load(cls, key):
        return cls.load_from(DEFAULT_SHELVE_NAME, key)


class Manager(Person):
    """
    Manager class that has special give_raise method
    """

    def __init__(self, name, age, pay, employees=2):
        Person.__init__(self, name, age, pay, 'manager')
        self.employees = employees

    def give_raise(self, percent, bonus):
        Person.give_raise(self, percent + bonus)


class PersonCUI:
    """
    console interface for persons
    """

    def start(self):
        while True:
            key = input('\nkey? => ')
            if not key:
                break
            try:
                record = Person.load(key)
            except:
                print('No such key "%s"!' % key)
            else:
                for field in record.__dict__.keys():
                    current_value = getattr(record, field)
                    new_value = input('\t[%s]=%s\n\tnew?=>' %
                                        (field, current_value))
                    if new_value:
                        setattr(record, field, eval(new_value))
                record.save()


class PersonGUI(tkinter.Frame):
    """
    graphical interface for persons
    """

    def __init__(self, parent=None):
        tkinter.Frame.__init__(self, parent)
        self.form = tkinter.Frame(self)
        self.entries = {}
        self.key_list = tkinter.Listbox(self)
        self.key_list.insert(0, 'NEW')
        db = shelve.open(DEFAULT_SHELVE_NAME)
        for key in db.keys():
            self.key_list.insert(tkinter.END, key)
        self.key_list.pack(side=tkinter.TOP)
        for (idx, string_label) in enumerate(Person('?', 0).__dict__.keys()):
            label = tkinter.Label(self.form, text=string_label)
            entry = tkinter.Entry(self.form)
            label.grid(row=idx, column=0)
            entry.grid(row=idx, column=1)
            self.entries[string_label] = entry
        fetch_button = tkinter.Button(self, text='Fetch',
                                      command=(lambda: self.fetch(
                                                self.key_list.get(self.key_list.curselection()))))
        update_button = tkinter.Button(self, text='Update',
                                       command=(lambda: self.update(
                                                self.key_list.get(self.key_list.curselection()))))
        self.form.pack()
        fetch_button.pack(side=tkinter.LEFT)
        update_button.pack(side=tkinter.LEFT)

    def fetch(self, key):
        try:
            record = Person.load(key)
        except:
            tkinter.messagebox.showerror(title='Error!',
                                         message='No such key "%s"!' % key)
        else:
            for field in record.__dict__.keys():
                self.entries[field].delete(0, tkinter.END)
                self.entries[field].insert(0, repr(getattr(record, field)))

    def update(self, key):
        new = False
        try:
            record = Person.load(key)
        except:
            record = Person('?', 0)
            new = True
        for field in record.__dict__.keys():
            setattr(record, field, eval(self.entries[field].get()))
        if new:
            self.key_list.insert(tkinter.END, record.key())
        record.save()


if __name__ == '__main__':
    #PersonCUI().start()
    window = tkinter.Tk()
    window.title('PeopleDB')
    form = PersonGUI(window)
    form.pack()
    window.mainloop()