RegionSnapshotService (Apache Geode 1.13.2)
Date: 2021-03-08

org.apache.geode.cache.snapshot

## Interface RegionSnapshotService<K,V>

- Type Parameters:
    `K` - the cache entry key type
    `V` - the cache entry value type

      public interface RegionSnapshotService<K,V>

  Allows a snapshot of region data to be imported and exported. Example usage:

       // obtain a snapshot
       RegionSnapshot snapshot = region.getSnapshotService();

       // export the snapshot, every region in the cache will be exported
       snapshot.save(new File("snapshot.gfd"), SnapshotOptions.GEMFIRE);

       // import the snapshot file, updates any existing entries in the region
       snapshot.load(new File("snapshot.gfd"), SnapshotOptions.GEMFIRE);

  When parallel export is used, the file name will be modified to include a unique identifier for the member that created the file, so providing a file location of "snapshot.gfd" would result in creation of multiple files with the format "snapshot-unique_id.gfd". When loading files from a parallel export, a directory can be given instead of a single file and all snapshot files in that directory will be loaded.

       // import directory of snapshot files
       snapshot.load(new File("snapshotDir"), SnapshotOptions.GEMFIRE);

  The default behavior is to perform all I/O operations on the node where the snapshot operations are invoked. This will involve either collecting or dispersing data over the network if the region is a partitioned region. The snapshot behavior can be changed using `SnapshotOptions`. For example:

       RegionSnapshotService snapshot = region.getSnapshotService();
       SnapshotFilter filter = new SnapshotFilter() {
         public boolean accept(Entry entry) {
           return true;
         }
       };

       SnapshotOptions options = snapshot.createOptions();
       options.setFilter(filter);

       snapshot.save(new File("snapshot.gfd"), SnapshotFormat.GEMFIRE, options);

  Note that the snapshot does not provide a consistency guarantee. Updates to data during the course of import/export operations could result data inconsistencies.
  Since:
    GemFire 7.0
  See Also:
    `Region.getSnapshotService()`, `SnapshotOptions`

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static String` | `SNAPSHOT_FILE_EXTENSION` File extension for snapshot files

  - ### Method Summary

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method and Description
    --- | ---
    `SnapshotOptions<K,V>` | `createOptions()` Creates a `SnapshotOptions` object configured with default settings.
    `void` | `load(File snapshot, SnapshotOptions.SnapshotFormat format)` Imports the snapshot file into the specified region.
    `void` | `load(File snapshot, SnapshotOptions.SnapshotFormat format, SnapshotOptions<K,V> options)` Imports the snapshot file into the specified region by applying user-configured options.
    `void` | `save(File snapshot, SnapshotOptions.SnapshotFormat format)` Exports the region data into the snapshot file.
    `void` | `save(File snapshot, SnapshotOptions.SnapshotFormat format, SnapshotOptions<K,V> options)` Exports the region data into the snapshot file by applying user-configured options.

- - ### Field Detail

    - #### SNAPSHOT_FILE_EXTENSION

          static final String SNAPSHOT_FILE_EXTENSION

      File extension for snapshot files
      See Also:
        Constant Field Values

  - ### Method Detail

    - #### createOptions

          SnapshotOptions<K,V> createOptions()

      Creates a `SnapshotOptions` object configured with default settings. The options can be used to configure snapshot behavior.
      Returns:
        the default options

    - #### save

          void save(File snapshot,
                    SnapshotOptions.SnapshotFormat format)
             throws IOException

      Exports the region data into the snapshot file.
      Parameters:
        `snapshot` - the snapshot file (must end in .gfd)
        `format` - the snapshot format
      Throws:
        `IOException` - error writing snapshot

    - #### save

          void save(File snapshot,
                    SnapshotOptions.SnapshotFormat format,
                    SnapshotOptions<K,V> options)
             throws IOException

      Exports the region data into the snapshot file by applying user-configured options.
      Parameters:
        `snapshot` - the snapshot file (must end in .gfd)
        `format` - the snapshot format
        `options` - the snapshot options
      Throws:
        `IOException` - error writing snapshot

    - #### load

          void load(File snapshot,
                    SnapshotOptions.SnapshotFormat format)
             throws IOException,
                    ClassNotFoundException

      Imports the snapshot file into the specified region. The snapshot parameter can be either a single snapshot file or a directory containing snapshot files. If a single file, it must end in the snapshot file extension (.gfd) to be imported. If a directory, only files in the directory that end in .gfd will be loaded.

      Prior to loading data, the region should have been created and any necessary serializers (either `DataSerializer` or `PdxSerializer`) and `Instantiator`s should have been registered.

      Parameters:
        `snapshot` - the snapshot file (ending in .gfd) or a directory of .gfd snapshot files
        `format` - the snapshot file format
      Throws:
        `IOException` - Unable to import data
        `ClassNotFoundException` - Unable to import data

    - #### load

          void load(File snapshot,
                    SnapshotOptions.SnapshotFormat format,
                    SnapshotOptions<K,V> options)
             throws IOException,
                    ClassNotFoundException

      Imports the snapshot file into the specified region by applying user-configured options. The snapshot parameter can be either a single snapshot file or a directory containing snapshot files. If a single file, it must end in the snapshot file extension (.gfd) to be imported. If a directory, only files in the directory that end in .gfd will be loaded.

      Prior to loading data, the region should have been created and any necessary serializers (either `DataSerializer` or `PdxSerializer`) and `Instantiator`s should have been registered.

      Parameters:
        `snapshot` - the snapshot file (ending in .gfd) or a directory of .gfd snapshot files
        `format` - the snapshot file format
        `options` - the snapshot options
      Throws:
        `IOException` - Unable to import data
        `ClassNotFoundException` - Unable to import data