org.gridgain.grid.spi.swapspace

Interface GridSwapSpaceSpi

All Superinterfaces:

GridSpi

All Known Implementing Classes:

GridFileSwapSpaceSpi, GridNoopSwapSpaceSpi

public interface GridSwapSpaceSpi
extends GridSpi

Provides a mechanism in grid for storing data on disk. GridGain cache uses swap space to overflow data to disk if it cannot fit in memory. It's also possible to use swap space directly by calling Grid API swap-related methods. Logically storage is organized into independent 'spaces' in which data is stored.

All swap space implementations can be configured to prevent infinite growth and evict oldest entries.

The default swap space SPI is GridFileSwapSpaceSpi which stores values on disk in files and keeps keys in memory.

Gridgain provides the following GridSwapSpaceSpi implementations:

• GridFileSwapSpaceSpi - pure Java implementation with in-memory keys. This SPI is used by default.
• GridNoopSwapSpaceSpi - no-op SPI mainly for testing.

NOTE: this SPI (i.e. methods in this interface) should never be used directly. SPIs provide internal view on the subsystem and is used internally by GridGain kernal. In rare use cases when access to a specific implementation of this SPI is required - an instance of this SPI can be obtained via Grid.configuration() method to check its configuration properties or call other non-SPI methods. Note again that calling methods from this interface on the obtained instance can lead to undefined behavior and explicitly not supported.

Method Summary

Methods

Modifier and Type	Method and Description
void	clear(String spaceName) Entirely clears data space with given name, if any.
long	count(String spaceName) Gets number of stored entries (keys) in data space with given name.
<K> GridSpiCloseableIterator<K>	keyIterator(String spaceName, GridSwapContext ctx) Gets iterator over space keys.
Collection<Integer>	partitions(String spaceName) Gets partitions IDs that are stored in the passed in space.
GridSpiCloseableIterator<Map.Entry<byte[],byte[]>>	rawIterator(String spaceName) Gets raw iterator over space entries.
GridSpiCloseableIterator<Map.Entry<byte[],byte[]>>	rawIterator(String spaceName, int part) Gets raw iterator over space entries.
byte[]	read(String spaceName, GridSwapKey key, GridSwapContext ctx) Reads stored value as array of bytes by key from data space with given name.
Map<GridSwapKey,byte[]>	readAll(String spaceName, Iterable<GridSwapKey> keys, GridSwapContext ctx) Reads stored values as array of bytes by all passed keys from data space with given name.
void	remove(String spaceName, GridSwapKey key, GridInClosure<byte[]> c, GridSwapContext ctx) Removes value stored in data space with given name corresponding to specified key.
void	removeAll(String spaceName, Collection<GridSwapKey> keys, GridBiInClosure<GridSwapKey,byte[]> c, GridSwapContext ctx) Removes values stored in data space with given name corresponding to specified keys.
void	setListener(GridSwapSpaceSpiListener evictLsnr) Sets eviction listener to receive notifications on evicted swap entries.
long	size(String spaceName) Gets size in bytes for data space with given name.
void	store(String spaceName, GridSwapKey key, byte[] val, GridSwapContext ctx) Stores value as array of bytes with given key into data space with given name.
void	storeAll(String spaceName, Map<GridSwapKey,byte[]> pairs, GridSwapContext ctx) Stores key-value pairs (both keys and values are arrays of bytes) into data space with given name.

Methods inherited from interface org.gridgain.grid.spi.GridSpi

getName, getNodeAttributes, onContextDestroyed, onContextInitialized, spiStart, spiStop

Method Detail

clear

void clear(@Nullable
         String spaceName)
           throws GridSpiException

Entirely clears data space with given name, if any.

Parameters:

spaceName - Space name to clear.

Throws:

GridSpiException - In case of any errors.

size

long size(@Nullable
        String spaceName)
          throws GridSpiException

Gets size in bytes for data space with given name. If specified space does not exist this method returns 0.

Parameters:

spaceName - Space name to get size for.

Returns:

Size in bytes.

Throws:

GridSpiException - In case of any errors.

count

long count(@Nullable
         String spaceName)
           throws GridSpiException

Gets number of stored entries (keys) in data space with given name. If specified space does not exist this method returns 0.

Parameters:

spaceName - Space name to get number of entries for.

Returns:

Number of stored entries in specified space.

Throws:

GridSpiException - In case of any errors.

read

@Nullable
byte[] read(@Nullable
                   String spaceName,
                   GridSwapKey key,
                   GridSwapContext ctx)
            throws GridSpiException

Reads stored value as array of bytes by key from data space with given name. If specified space does not exist this method returns null.

Parameters:

spaceName - Name of the data space to read from.

key - Key used to read value from data space.

ctx - Swap context.

Returns:

Value as array of bytes stored in specified data space that matches to given key.

Throws:

GridSpiException - In case of any errors.

readAll

Map<GridSwapKey,byte[]> readAll(@Nullable
                              String spaceName,
                              Iterable<GridSwapKey> keys,
                              GridSwapContext ctx)
                                throws GridSpiException

Reads stored values as array of bytes by all passed keys from data space with given name. If specified space does not exist this method returns empty map.

Parameters:

spaceName - Name of the data space to read from.

keys - Keys used to read values from data space.

ctx - Swap context.

Returns:

Map in which keys are the ones passed into method and values are corresponding values read from swap storage.

Throws:

GridSpiException - In case of any errors.

remove

void remove(@Nullable
          String spaceName,
          GridSwapKey key,
          @Nullable
          GridInClosure<byte[]> c,
          GridSwapContext ctx)
            throws GridSpiException

Removes value stored in data space with given name corresponding to specified key.

Parameters:

spaceName - Space name to remove value from.

key - Key to remove value in the specified space for.

c - Optional closure that takes removed value and executes after actual removing. If there was no value in storage the closure is not executed.

ctx - Swap context.

Throws:

GridSpiException - In case of any errors.

removeAll

void removeAll(@Nullable
             String spaceName,
             Collection<GridSwapKey> keys,
             @Nullable
             GridBiInClosure<GridSwapKey,byte[]> c,
             GridSwapContext ctx)
               throws GridSpiException

Removes values stored in data space with given name corresponding to specified keys.

Parameters:

spaceName - Space name to remove values from.

keys - Keys to remove value in the specified space for.

c - Optional closure that takes removed value and executes after actual removing. If there was no value in storage the closure is not executed.

ctx - Swap context.

Throws:

GridSpiException - In case of any errors.

store

void store(@Nullable
         String spaceName,
         GridSwapKey key,
         @Nullable
         byte[] val,
         GridSwapContext ctx)
           throws GridSpiException

Stores value as array of bytes with given key into data space with given name.

Parameters:

spaceName - Space name to store key-value pair into.

key - Key to store given value for. This key can be used further to read or remove stored value.

val - Some value as array of bytes to store into specified data space.

ctx - Swap context.

Throws:

GridSpiException - In case of any errors.

storeAll

void storeAll(@Nullable
            String spaceName,
            Map<GridSwapKey,byte[]> pairs,
            GridSwapContext ctx)
              throws GridSpiException

Stores key-value pairs (both keys and values are arrays of bytes) into data space with given name.

Parameters:

spaceName - Space name to store key-value pairs into.

pairs - Map of stored key-value pairs where each one is an array of bytes.

ctx - Swap context.

Throws:

GridSpiException - In case of any errors.

setListener

void setListener(@Nullable
               GridSwapSpaceSpiListener evictLsnr)

Sets eviction listener to receive notifications on evicted swap entries.

Parameters:

evictLsnr - Eviction listener (null to stop receiving notifications).

partitions

@Nullable
Collection<Integer> partitions(@Nullable
                                      String spaceName)
                               throws GridSpiException

Gets partitions IDs that are stored in the passed in space.

Parameters:

spaceName - Space name.

Returns:

Partitions IDs or null if space is unknown.

Throws:

GridSpiException - If failed.

keyIterator

@Nullable
<K> GridSpiCloseableIterator<K> keyIterator(@Nullable
                                                   String spaceName,
                                                   GridSwapContext ctx)
                                        throws GridSpiException

Gets iterator over space keys.

Parameters:

spaceName - Space name.

ctx - Swap context.

Returns:

Iterator over space entries or null if space is unknown.

Throws:

GridSpiException - If failed.

rawIterator

@Nullable
GridSpiCloseableIterator<Map.Entry<byte[],byte[]>> rawIterator(@Nullable
                                                                      String spaceName)
                                                               throws GridSpiException

Gets raw iterator over space entries.

Parameters:

spaceName - Space name.

Returns:

Iterator over space entries or null if space is unknown.

Throws:

GridSpiException - If failed.

rawIterator

@Nullable
GridSpiCloseableIterator<Map.Entry<byte[],byte[]>> rawIterator(@Nullable
                                                                      String spaceName,
                                                                      int part)
                                                               throws GridSpiException

Gets raw iterator over space entries.

Parameters:

spaceName - Space name.

part - Partition.

Returns:

Iterator over space entries or null if space is unknown.

Throws:

GridSpiException - If failed.