Python中值变化时触发函数的实现方法及Odoo假期池计算方法修改需求

Depending on your scenario, there are a few practical ways to achieve this:

Using Python Properties #

For simple class attributes, properties are the most straightforward approach. You can define a setter that checks if the new value differs from the old one, then fires your target function:

class MyClass:
    def __init__(self):
        self._value = None

    @property
    def value(self):
        return self._value

    @value.setter
    def value(self, new_val):
        if new_val != self._value:
            self._value = new_val
            self._on_value_change()

    def _on_value_change(self):
        print("Value updated! Triggering related logic...")

Observer Pattern #

If multiple components need to react to value changes, the observer pattern is ideal. It lets you register "observers" that get notified whenever the value updates:

class ObservableValue:
    def __init__(self):
        self._observers = []
        self._current_value = None

    @property
    def value(self):
        return self._current_value

    @value.setter
    def value(self, new_val):
        if new_val != self._current_value:
            self._current_value = new_val
            self._notify_observers()

    def add_observer(self, observer):
        self._observers.append(observer)

    def _notify_observers(self):
        for observer in self._observers:
            observer.on_value_update(self._current_value)

class ValueObserver:
    def on_value_update(self, value):
        print(f"Received updated value: {value}")

# Example usage
my_value = ObservableValue()
observer = ValueObserver()
my_value.add_observer(observer)
my_value.value = 42  # Triggers the observer's update method

Odoo-Specific Methods #

Since your second question relates to Odoo, here's how to handle field changes in the Odoo ecosystem:

• Computed Fields: Use the @api.depends decorator to trigger a computed method when specific fields change.
• Override Write: Override the write method to compare old and new field values, then run your logic if a change is detected.
• Tracking: Add tracking=True to a field to log changes, then react to those logs in related methods.

Let's break down your requirement: you want to skip action when annual_leave changes, but increment remaining_count (from your holiday pool) when it doesn't. Here's how to adjust your code:

Assumptions #

• annual_leave is a field on your model (we'll cover an alternative if you meant the annual holiday count from the search below).
• You want to add 1 to remaining_count when setting current_holiday_pool only if annual_leave hasn't changed.

Step 1: Update the Depends Decorator #

First, ensure your computed method triggers when annual_leave changes by adding it to the @api.depends list:

@api.multi
@api.depends('yearly_holidays_ids', 'annual_leave')  # Add annual_leave here
def _get_current_holiday_pool(self):

Step 2: Check for Changes and Adjust Logic #

Use Odoo's has_changed method to detect if annual_leave was modified in the current write operation. Then adjust the current_holiday_pool calculation accordingly:

from odoo import api, models, fields
import datetime

class YourModel(models.Model):
    _name = 'your.model.name'  # Replace with your actual model name

    annual_leave = fields.Integer(string='Annual Leave')
    current_holiday_pool = fields.Float(compute='_get_current_holiday_pool', store=True, string='Current Holiday Pool')
    yearly_holidays_ids = fields.One2many('yearly.holidays', 'related_model_id', string='Yearly Holidays')

    @api.multi
    @api.depends('yearly_holidays_ids', 'annual_leave')
    def _get_current_holiday_pool(self):
        for record in self:
            # Skip logic if annual_leave changed in this write
            if record.has_changed('annual_leave'):
                continue

            current_year = datetime.date.today().year
            total_holidays = record.yearly_holidays_ids.filtered(lambda lm: lm.year == current_year)
            annual_leaves_count = self.env['hr.holidays'].search_count([('holiday_status_id.name', '=', 'annual')])

            if annual_leaves_count > 1:
                if total_holidays:
                    record.current_holiday_pool = total_holidays[0].remaining_count + 1
            elif annual_leaves_count == 1:
                if total_holidays:
                    record.current_holiday_pool = total_holidays.remaining_count + 1
            else:
                record.current_holiday_pool = 0

Alternative: If annual_leave refers to the search count #

If you meant the annual_leaves_count from the search_count call instead of a model field, you'll need to store the previous count to compare. Add a field like last_annual_leaves_count to track it:

last_annual_leaves_count = fields.Integer(string='Last Annual Leaves Count', store=True)

@api.multi
@api.depends('yearly_holidays_ids')
def _get_current_holiday_pool(self):
    for record in self:
        current_year = datetime.date.today().year
        total_holidays = record.yearly_holidays_ids.filtered(lambda lm: lm.year == current_year)
        annual_leaves_count = self.env['hr.holidays'].search_count([('holiday_status_id.name', '=', 'annual')])

        # Compare current count with stored last count
        if annual_leaves_count != record.last_annual_leaves_count:
            record.last_annual_leaves_count = annual_leaves_count
            continue

        # Increment remaining_count since the count didn't change
        if annual_leaves_count > 1:
            if total_holidays:
                record.current_holiday_pool = total_holidays[0].remaining_count + 1
        elif annual_leaves_count == 1:
            if total_holidays:
                record.current_holiday_pool = total_holidays.remaining_count + 1
        else:
            record.current_holiday_pool = 0

Key Notes #

• The has_changed method only works during write operations; use a stored field if you need to track changes across sessions.
• Always handle empty total_holidays to avoid AttributeErrors.
• Add store=True to current_holiday_pool if you want to persist the computed value.

内容的提问来源于stack exchange，提问作者SaltySteven