org.axonframework.eventstore.fs

Class SimpleEventFileResolver

java.lang.Object

org.axonframework.eventstore.fs.SimpleEventFileResolver

All Implemented Interfaces:

EventFileResolver

public class SimpleEventFileResolver
extends Object
implements EventFileResolver

Very straightforward implementation of the EventFileResolver that stores files in a directory structure underneath a given base directory. Events of a single aggregate are appended to a pair of files, one for regular events and one for snapshot events. Directories are used to separate files for different aggregate types.

Since:

0.5

Author:

Allard Buijze

Field Summary

Fields

Modifier and Type	Field and Description
static String	FILE_EXTENSION_EVENTS Describes the file extension used for files containing domain events.
static String	FILE_EXTENSION_SNAPSHOTS Describes the file extension used for files containing snapshot events.

Constructor Summary

Constructors

Constructor and Description
SimpleEventFileResolver(File baseDir) Initialize the SimpleEventFileResolver with the given baseDir.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	eventFileExists(String type, Object identifier) Indicates whether there is a file containing (regular) events for the given aggregateIdentifier of given type.
InputStream	openEventFileForReading(String type, Object identifier) Provides an input stream to the (regular) events file for the aggregate with the given aggregateIdentifier and of given type.
OutputStream	openEventFileForWriting(String type, Object aggregateIdentifier) Provides an output stream to the (regular) events file for the aggregate with the given aggregateIdentifier and of given type.
InputStream	openSnapshotFileForReading(String type, Object identifier) Provides an input stream to the snapshot events file for the aggregate with the given aggregateIdentifier and of given type.
OutputStream	openSnapshotFileForWriting(String type, Object aggregateIdentifier) Provides an output stream to the snapshot events file for the aggregate with the given aggregateIdentifier and of given type.
boolean	snapshotFileExists(String type, Object identifier) Indicates whether there is a file containing snapshot events for the given aggregateIdentifier of given type.

Methods inherited from class java.lang.Object

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

Field Detail

FILE_EXTENSION_EVENTS

public static final String FILE_EXTENSION_EVENTS

Describes the file extension used for files containing domain events.

See Also:

Constant Field Values

FILE_EXTENSION_SNAPSHOTS

public static final String FILE_EXTENSION_SNAPSHOTS

Describes the file extension used for files containing snapshot events.

See Also:

Constant Field Values

Constructor Detail

SimpleEventFileResolver

public SimpleEventFileResolver(File baseDir)

Initialize the SimpleEventFileResolver with the given baseDir.

Note that the resource supplied must point to a folder and should contain a trailing slash. See org.springframework.core.io.FileSystemResource#FileSystemResource(String).

Parameters:

baseDir - The directory where event files are stored.

Method Detail

openEventFileForWriting

public OutputStream openEventFileForWriting(String type,
                                   Object aggregateIdentifier)
                                     throws IOException

Description copied from interface: EventFileResolver

Provides an output stream to the (regular) events file for the aggregate with the given aggregateIdentifier and of given type. Written bytes are appended to already existing information.

The caller of this method is responsible for closing the output stream when all data has been written to it.

Specified by:

openEventFileForWriting in interface EventFileResolver

Parameters:

type - The type of aggregate to open the stream for

aggregateIdentifier - the identifier of the aggregate

Returns:

an OutputStream that appends to the event log of of the given aggregate

Throws:

IOException - when an error occurs while opening a file

openSnapshotFileForWriting

public OutputStream openSnapshotFileForWriting(String type,
                                      Object aggregateIdentifier)
                                        throws IOException

Description copied from interface: EventFileResolver

Provides an output stream to the snapshot events file for the aggregate with the given aggregateIdentifier and of given type. Written bytes are appended to already existing information.

The caller of this method is responsible for closing the output stream when all data has been written to it.

Specified by:

openSnapshotFileForWriting in interface EventFileResolver

Parameters:

type - The type of aggregate to open the stream for

aggregateIdentifier - the identifier of the aggregate

Returns:

an OutputStream that appends to the snapshot event log of of the given aggregate

Throws:

IOException - when an error occurs while opening a file

openEventFileForReading

public InputStream openEventFileForReading(String type,
                                  Object identifier)
                                    throws IOException

Description copied from interface: EventFileResolver

Provides an input stream to the (regular) events file for the aggregate with the given aggregateIdentifier and of given type.

The caller of this method is responsible for closing the input stream when done reading from it.

Specified by:

openEventFileForReading in interface EventFileResolver

Parameters:

type - The type of aggregate to open the stream for

identifier - the identifier of the aggregate

Returns:

an InputStream that reads from the event log of of the given aggregate

Throws:

IOException - when an error occurs while opening a file

openSnapshotFileForReading

public InputStream openSnapshotFileForReading(String type,
                                     Object identifier)
                                       throws IOException

Description copied from interface: EventFileResolver

Provides an input stream to the snapshot events file for the aggregate with the given aggregateIdentifier and of given type.

The caller of this method is responsible for closing the input stream when done reading from it.

Specified by:

openSnapshotFileForReading in interface EventFileResolver

Parameters:

type - The type of aggregate to open the stream for

identifier - the identifier of the aggregate

Returns:

an InputStream that reads from the snapshot event log of of the given aggregate

Throws:

IOException - when an error occurs while opening a file

eventFileExists

public boolean eventFileExists(String type,
                      Object identifier)
                        throws IOException

Description copied from interface: EventFileResolver

Indicates whether there is a file containing (regular) events for the given aggregateIdentifier of given type.

Specified by:

eventFileExists in interface EventFileResolver

Parameters:

type - The type of aggregate

identifier - the identifier of the aggregate

Returns:

true if an event log exists for the aggregate, false otherwise.

Throws:

IOException - when an error occurs while reading from the FileSystem. The existence of the event file is undetermined.

snapshotFileExists

public boolean snapshotFileExists(String type,
                         Object identifier)
                           throws IOException

Description copied from interface: EventFileResolver

Indicates whether there is a file containing snapshot events for the given aggregateIdentifier of given type.

Specified by:

snapshotFileExists in interface EventFileResolver

Parameters:

type - The type of aggregate

identifier - the identifier of the aggregate

Returns:

true if a snapshot event log exists for the aggregate, false otherwise.

Throws:

IOException - when an error occurs while reading from the FileSystem. The existence of the event file is undetermined.