fix: Rename SlidingWindowCompactor to LlmEventSummarizer and refine its docstring

The class is now named `LlmEventSummarizer` to better reflect that its primary function is to use an LLM to summarize events. The docstring has been updated to clarify that this class is responsible *only* for the LLM-based summarization of a given set of events, while the logic for determining *when* and *which* events form the sliding window is handled by an external component, such as an ADK Runner. PiperOrigin-RevId: 815976264

Author: hangfei

src/google/adk/apps/sliding_window_compactor.py renamed to src/google/adk/apps/llm_event_summarizer.py

@@ -27,31 +27,23 @@
 from .base_events_compactor import BaseEventsCompactor
 
 
-class SlidingWindowCompactor(BaseEventsCompactor):
- """A summarizer for Sliding Window Compaction logic in Runner.
-
- This compactor works with ADK runner to provide sliding window compaction.
- The runner uses `compaction_invocation_threshold` and `overlap_size`
- configured in `EventsCompactionConfig` on the `App` to determine when to
- trigger compaction and which events to compact. This class performs
- summarization of events passed by the runner.
-
- The compaction process is controlled by two parameters read by the Runner from
- `EventsCompactionConfig`:
- 1. `compaction_invocation_threshold`: The number of *new* user-initiated
- invocations that, once fully
- represented in the session's events, will trigger a compaction.
- 2. `overlap_size`: The number of preceding invocations to include from the
- end of the last
- compacted range. This creates an overlap between consecutive compacted
- summaries,
- maintaining context.
-
- When `Runner` determines compaction is needed based on
- `compaction_invocation_threshold`,
- it selects a range of events based on `overlap_size` and passes them to
- `maybe_compact_events` for summarization into a `CompactedEvent`.
- This `CompactedEvent` is then appended to the session by the `Runner`.
+class LlmEventSummarizer(BaseEventsCompactor):
+ """An LLM-based event summarizer for sliding window compaction.
+
+ This class is responsible for summarizing a provided list of events into a
+ single compacted event. It is designed to be used as part of a sliding window
+ compaction process.
+
+ The actual logic for determining *when* to trigger compaction and *which*
+ events form the sliding window (based on parameters like
+ `compaction_invocation_threshold` and `overlap_size` from
+ `EventsCompactionConfig`) is handled by an external component, such as an ADK
+ "Runner". This compactor focuses solely on generating a summary of the events
+ it receives.
+
+ When `maybe_compact_events` is called with a list of events, this class
+ formats the events, generates a summary using an LLM, and returns a new
+ `Event` containing the summary within an `EventCompaction`.
  """
 
  _DEFAULT_PROMPT_TEMPLATE = (
@@ -68,7 +60,7 @@ def __init__(
  llm: BaseLlm,
  prompt_template: Optional[str] = None,
  ):
- """Initializes the SlidingWindowCompactor.
+ """Initializes the LlmEventSummarizer.
 
  Args:
  llm: The LLM used for summarization.

src/google/adk/runners.py

@@ -28,7 +28,6 @@
 import warnings
 
 from google.adk.apps.compaction import _run_compaction_for_sliding_window
-from google.adk.apps.sliding_window_compactor import SlidingWindowCompactor
 from google.genai import types
 
 from .agents.active_streaming_tool import ActiveStreamingTool

tests/unittests/apps/test_compaction.py

@@ -20,7 +20,7 @@
 from google.adk.apps.app import App
 from google.adk.apps.app import EventsCompactionConfig
 from google.adk.apps.compaction import _run_compaction_for_sliding_window
-from google.adk.apps.sliding_window_compactor import SlidingWindowCompactor
+from google.adk.apps.llm_event_summarizer import LlmEventSummarizer
 from google.adk.events.event import Event
 from google.adk.events.event_actions import EventActions
 from google.adk.events.event_actions import EventCompaction
@@ -38,7 +38,7 @@ class TestCompaction(unittest.IsolatedAsyncioTestCase):
 
  def setUp(self):
  self.mock_session_service = AsyncMock(spec=BaseSessionService)
- self.mock_compactor = AsyncMock(spec=SlidingWindowCompactor)
+ self.mock_compactor = AsyncMock(spec=LlmEventSummarizer)
 
  def _create_event(
  self, timestamp: float, invocation_id: str, text: str

tests/unittests/apps/test_sliding_window_compactor.py renamed to tests/unittests/apps/test_llm_event_summarizer.py

@@ -16,7 +16,7 @@
 from unittest.mock import AsyncMock
 from unittest.mock import Mock
 
-from google.adk.apps.sliding_window_compactor import SlidingWindowCompactor
+from google.adk.apps.llm_event_summarizer import LlmEventSummarizer
 from google.adk.events.event import Event
 from google.adk.events.event_actions import EventActions
 from google.adk.events.event_actions import EventCompaction
@@ -32,12 +32,12 @@
 @pytest.mark.parametrize(
  'env_variables', ['GOOGLE_AI', 'VERTEX'], indirect=True
 )
-class TestSlidingWindowCompactor(unittest.IsolatedAsyncioTestCase):
+class TestLlmEventSummarizer(unittest.IsolatedAsyncioTestCase):
 
  def setUp(self):
  self.mock_llm = AsyncMock(spec=BaseLlm)
  self.mock_llm.model = 'test-model'
- self.compactor = SlidingWindowCompactor(llm=self.mock_llm)
+ self.compactor = LlmEventSummarizer(llm=self.mock_llm)
 
  def _create_event(
  self, timestamp: float, text: str, author: str = 'user'