Package org.bsc.langgraph4j.checkpoint

Class FileSystemSaver

java.lang.Object

org.bsc.langgraph4j.checkpoint.AbstractCheckpointSaver

org.bsc.langgraph4j.checkpoint.FileSystemSaver

All Implemented Interfaces:

BaseCheckpointSaver, LG4JLoggable

public class FileSystemSaver
extends AbstractCheckpointSaver
implements LG4JLoggable

A CheckpointSaver that stores Checkpoints in the filesystem.

Each RunnableConfig is associated with a file in the provided targetFolder. The file is named "thread-threadId.saver" if the RunnableConfig has a threadId, or "thread-$default.saver" if it doesn't.

Nested Class Summary

Nested classes/interfaces inherited from interface org.bsc.langgraph4j.checkpoint.BaseCheckpointSaver

BaseCheckpointSaver.Tag

Field Summary

Fields inherited from interface org.bsc.langgraph4j.checkpoint.BaseCheckpointSaver

THREAD_ID_DEFAULT

Fields inherited from interface org.bsc.langgraph4j.LG4JLoggable

log

Constructor Summary

Constructors

Constructor	Description
FileSystemSaver(Path targetFolder, Serializer<LinkedList<Checkpoint>> checkpointsSerializer)
FileSystemSaver(Path targetFolder, StateSerializer<? extends AgentState> stateSerializer)

Method Summary

Modifier and Type	Method	Description
boolean	deleteFile(RunnableConfig config)	delete the checkpoint file associated with the given RunnableConfig.
protected void	insertedCheckpoint(RunnableConfig config, LinkedList<Checkpoint> checkpoints, Checkpoint checkpoint)
protected LinkedList<Checkpoint>	loadCheckpoints(RunnableConfig config)
protected BaseCheckpointSaver.Tag	releaseCheckpoints(RunnableConfig config, LinkedList<Checkpoint> checkpoints)	Releases the checkpoints associated with the given configuration.
protected void	updatedCheckpoint(RunnableConfig config, LinkedList<Checkpoint> checkpoints, Checkpoint checkpoint)

Methods inherited from class org.bsc.langgraph4j.checkpoint.AbstractCheckpointSaver

get, list, put, release

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.bsc.langgraph4j.checkpoint.BaseCheckpointSaver

threadId

Constructor Details

FileSystemSaver

public FileSystemSaver(Path targetFolder,
 Serializer<LinkedList<Checkpoint>> checkpointsSerializer)

FileSystemSaver

public FileSystemSaver(Path targetFolder,
 StateSerializer<? extends AgentState> stateSerializer)

Method Details

insertedCheckpoint

protected void insertedCheckpoint(RunnableConfig config,
 LinkedList<Checkpoint> checkpoints,
 Checkpoint checkpoint)
                           throws Exception

Specified by:

insertedCheckpoint in class AbstractCheckpointSaver

Throws:

Exception

updatedCheckpoint

protected void updatedCheckpoint(RunnableConfig config,
 LinkedList<Checkpoint> checkpoints,
 Checkpoint checkpoint)
                          throws Exception

Specified by:

updatedCheckpoint in class AbstractCheckpointSaver

Throws:

Exception

loadCheckpoints

protected LinkedList<Checkpoint> loadCheckpoints(RunnableConfig config)
                                          throws Exception

Specified by:

loadCheckpoints in class AbstractCheckpointSaver

Throws:

Exception

releaseCheckpoints

protected BaseCheckpointSaver.Tag releaseCheckpoints(RunnableConfig config,
 LinkedList<Checkpoint> checkpoints)
                                              throws Exception

Releases the checkpoints associated with the given configuration. This involves copying the current checkpoint file (e.g., "thread-123.saver") to a versioned backup file (e.g., "thread-123-v1.saver", "thread-123-v2.saver", etc.) based on existing versioned files, deleting the original unversioned file, and then clearing the in-memory checkpoints.

Specified by:

releaseCheckpoints in class AbstractCheckpointSaver

Parameters:

config - The configuration for which to release checkpoints.

checkpoints - released checkpoints

Throws:

Exception - If an error occurs during file operations or releasing from memory.

deleteFile

public boolean deleteFile(RunnableConfig config)

delete the checkpoint file associated with the given RunnableConfig.

Parameters:

config - the RunnableConfig for which the checkpoint file should be cleared

Returns:

true if the file existed and was successfully deleted, false otherwise