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[FLINK-28921][python][docs] Optimize the Python DataStream Window Documentation #20557

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[FLINK-28921][python][docs] Optimize the Python DataStream Window Documentation #20557

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126 changes: 82 additions & 44 deletions docs/content.zh/docs/dev/datastream/operators/windows.md
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Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,9 @@ under the License.

**Keyed Windows**

{{< tabs "Keyed Windows" >}}

{{< tab "Java/Scala" >}}
stream
.keyBy(...) <- 仅 keyed 窗口需要
.window(...) <- 必填项："assigner"
Expand All @@ -45,8 +48,26 @@ under the License.
.reduce/aggregate/apply() <- 必填项："function"
[.getSideOutput(...)] <- 可选项："output tag"

{{< /tab >}}

{{< tab "Python" >}}
stream
.key_by(...) <- 仅 keyed 窗口需要
.window(...) <- 必填项："assigner"
[.trigger(...)] <- 可选项："trigger" (省略则使用默认 trigger)
[.allowed_lateness(...)] <- 可选项："lateness" (省略则为 0)
[.side_output_late_data(...)] <- 可选项："output tag" (省略则不对迟到数据使用 side output)
.reduce/aggregate/apply() <- 必填项："function"
[.get_side_output(...)] <- 可选项："output tag"

{{< /tab >}}
{{< /tabs >}}

**Non-Keyed Windows**

{{< tabs "Non-Keyed Windows" >}}

{{< tab "Java/Scala" >}}
stream
.windowAll(...) <- 必填项："assigner"
[.trigger(...)] <- 可选项："trigger" (else default trigger)
Expand All @@ -56,8 +77,23 @@ under the License.
.reduce/aggregate/apply() <- 必填项："function"
[.getSideOutput(...)] <- 可选项："output tag"

{{< /tab >}}

{{< tab "Python" >}}
stream
.window_all(...) <- 必填项："assigner"
[.trigger(...)] <- 可选项："trigger" (else default trigger)
[.allowed_lateness(...)] <- 可选项："lateness" (else zero)
[.side_output_late_data(...)] <- 可选项："output tag" (else no side output for late data)
.reduce/aggregate/apply() <- 必填项："function"
[.get_side_output(...)] <- 可选项："output tag"

{{< /tab >}}

{{< /tabs >}}

上面方括号（[...]）中的命令是可选的。也就是说，Flink 允许你自定义多样化的窗口操作来满足你的需求。
{{< hint info >}} Note: Non-Keyed windows 在 Python DataStream API 中还不支持. {{< /hint >}}
{{< hint info >}} Note: `Evictor` 在 Python DataStream API 中还不支持. {{< /hint >}}


## 窗口的生命周期
Expand Down Expand Up @@ -813,51 +849,51 @@ class ProcessWindowFunction(Function, Generic[IN, OUT, KEY, W]):
"""
pass

class Context(ABC, Generic[W2]):
"""
The context holding window metadata.
"""

@abstractmethod
def window(self) -> W2:
"""
:return: The window that is being evaluated.
"""
pass

@abstractmethod
def current_processing_time(self) -> int:
"""
:return: The current processing time.
"""
pass

@abstractmethod
def current_watermark(self) -> int:
"""
:return: The current event-time watermark.
"""
pass

@abstractmethod
def window_state(self) -> KeyedStateStore:
class Context(ABC, Generic[W2]):
"""
State accessor for per-key and per-window state.

.. note::
If you use per-window state you have to ensure that you clean it up by implementing
:func:`~ProcessWindowFunction.clear`.

:return: The :class:`KeyedStateStore` used to access per-key and per-window states.
The context holding window metadata.
"""
pass

@abstractmethod
def global_state(self) -> KeyedStateStore:
"""
State accessor for per-key global state.
"""
pass

@abstractmethod
def window(self) -> W2:
"""
:return: The window that is being evaluated.
"""
pass

@abstractmethod
def current_processing_time(self) -> int:
"""
:return: The current processing time.
"""
pass

@abstractmethod
def current_watermark(self) -> int:
"""
:return: The current event-time watermark.
"""
pass

@abstractmethod
def window_state(self) -> KeyedStateStore:
"""
State accessor for per-key and per-window state.

.. note::
If you use per-window state you have to ensure that you clean it up by implementing
:func:`~ProcessWindowFunction.clear`.

:return: The :class:`KeyedStateStore` used to access per-key and per-window states.
"""
pass

@abstractmethod
def global_state(self) -> KeyedStateStore:
"""
State accessor for per-key global state.
"""
pass
```
{{< /tab >}}
{{< /tabs >}}
Expand Down Expand Up @@ -1413,6 +1449,8 @@ Flink 内置有三个 evictor：
指定一个 evictor 可以避免预聚合，因为窗口中的所有元素在计算前都必须经过 evictor。
{{< /hint >}}

{{< hint info >}} Note: `Evictor` 在 Python DataStream API 中还不支持. {{< /hint >}}

Flink 不对窗口中元素的顺序做任何保证。也就是说，即使 evictor 从窗口缓存的开头移除一个元素，这个元素也不一定是最先或者最后到达窗口的。


Expand Down
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