org.magnos.data.store
Class MemoryStore

java.lang.Object
  org.magnos.data.store.AbstractStore
      org.magnos.data.store.MemoryStore

All Implemented Interfaces:

Store

public class MemoryStore
extends AbstractStore

A store which is kept entirely in memory and is not persisted to any medium.

Author:

Philip Diffenderfer

Constructor Summary

MemoryStore(java.lang.String name)
Instantiates a MemoryStore.

MemoryStore(java.lang.String name, int capacity)
Instantiates a MemoryStore.

MemoryStore(java.lang.String name, StoreAccess access, int capacity)
Instantiates a MemoryStore.

Method Summary

java.nio.ByteBuffer	getBuffer() Returns the buffer which contains all this stores data.
protected void	storeClose() Should close the store.
protected void	storeDelete() Deletes the medium to which the store has been persisting to.
protected boolean	storeExists() Returns whether the store exists in its probable medium.
protected void	storeFlush() Should flush the contents of the store from memory to a persisted medium if the implementation supports it.
protected void	storeGet(int location, byte[] bytes, int offset, int length) Gets data at the given location and stores it in the given byte array.
protected void	storeGet(int location, java.nio.ByteBuffer b) Gets data at the given location and stores it in the given ByteBuffer.
protected void	storeLoad() Should load contents of the store into memory from a persisted medium if the implementation supports it.
protected int	storeOpen(StoreAccess access) Should open the store and return the capacity.
protected void	storePut(int location, byte[] bytes, int offset, int length) Puts data at the given location from the given byte array.
protected void	storePut(int location, java.nio.ByteBuffer b) Puts data at the given location from the given ByteBuffer.
protected int	storeResize(int bytes) Resizes the store to the given capacity.

Methods inherited from class org.magnos.data.store.AbstractStore

capacity, capacity, close, create, delete, equals, exists, flush, get, get, get, get, getAccess, getName, hashCode, isAutoFlush, isAutoLoad, isAutoOpen, isClosed, isOpen, load, open, put, put, put, setAccess, setAutoFlush, setAutoLoad, setAutoOpen, toString, validate

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

MemoryStore

public MemoryStore(java.lang.String name)

Instantiates a MemoryStore.

Parameters:

name - The unique name of the Store.

MemoryStore

public MemoryStore(java.lang.String name,
                   int capacity)

Instantiates a MemoryStore.

Parameters:

name - The unique name of the Store.

capacity - The requested capacity of the store.

MemoryStore

public MemoryStore(java.lang.String name,
                   StoreAccess access,
                   int capacity)

Instantiates a MemoryStore.

Parameters:

name - The unique name of the Store.

access - The requested access to the store.

capacity - The requested capacity of the store.

Method Detail

getBuffer

public java.nio.ByteBuffer getBuffer()

Returns the buffer which contains all this stores data.

Returns:

The reference to the underlying buffer.

storeOpen

protected int storeOpen(StoreAccess access)
                 throws java.io.IOException

Should open the store and return the capacity. If the requested access could not be granted an exception should be thrown. This will only be invoked if the store has been closed previously or has not been opened yet. If the store doesn't exist this should forcefully create it before opening it with the requested access.

Specified by:

storeOpen in class AbstractStore

Returns:

The capacity of the store.

Throws:

java.io.IOException - An error occurred opening the store with the given access.

storeLoad

protected void storeLoad()
                  throws java.io.IOException

Should load contents of the store into memory from a persisted medium if the implementation supports it.

Specified by:

storeLoad in class AbstractStore

Throws:

java.io.IOException - An error occurred loading the store.

storeFlush

protected void storeFlush()
                   throws java.io.IOException

Should flush the contents of the store from memory to a persisted medium if the implementation supports it.

Specified by:

storeFlush in class AbstractStore

Throws:

java.io.IOException - An error occurred flushing the store.

storeClose

protected void storeClose()
                   throws java.io.IOException

Should close the store. This will only be invoked if the store has been successfully opened previously. If there is an error closing the store an exception should be thrown. This exception however may be ignored due to the likeliness that the store is still closed even after an exception is thrown.

Specified by:

storeClose in class AbstractStore

Throws:

java.io.IOException - An error occurred closing the store.

storeDelete

protected void storeDelete()

Deletes the medium to which the store has been persisting to.

Specified by:

storeDelete in class AbstractStore

storeExists

protected boolean storeExists()

Returns whether the store exists in its probable medium. This could be called before or after the store has been opened or created.

Specified by:

storeExists in class AbstractStore

Returns:

True if the store already exists.

storeResize

protected int storeResize(int bytes)

Resizes the store to the given capacity. If the store could not be resized to the requested capacity an exception should be thrown. This will only be called if the store was successfully opened previously. If the resize results in a larger store the end of the store should be padded with zeros (which the system will implicitly due most likely).

Specified by:

storeResize in class AbstractStore

Parameters:

bytes - The new capacity of the store.

storeGet

protected void storeGet(int location,
                        byte[] bytes,
                        int offset,
                        int length)
                 throws java.io.IOException

Gets data at the given location and stores it in the given byte array.

Specified by:

storeGet in class AbstractStore

Parameters:

location - The offset to get the data, in bytes, from the beginning of the store.

bytes - The array of bytes to place the data in.

offset - The offset in the byte array to place the data.

length - The number of bytes to copy from the store and place in the array.

Throws:

java.io.IOException - An error occurred reading from the store.

storePut

protected void storePut(int location,
                        byte[] bytes,
                        int offset,
                        int length)
                 throws java.io.IOException

Puts data at the given location from the given byte array.

Specified by:

storePut in class AbstractStore

Parameters:

location - The offset to put the data, in bytes, from the beginning of the store.

bytes - The array of bytes to take data from.

offset - The offset in the byte array to take the data.

length - The number of bytes to copy from the array and place in the store.

Throws:

java.io.IOException - An error occurred writing to the store.

storeGet

protected void storeGet(int location,
                        java.nio.ByteBuffer b)
                 throws java.io.IOException

Gets data at the given location and stores it in the given ByteBuffer.

Specified by:

storeGet in class AbstractStore

Parameters:

location - The offset to get the data, in bytes, from the beginning of the store.

b - The buffer to place the data in. The buffer will be filled with data to its limit (so it has no remaining bytes).

Throws:

java.io.IOException - An error occurred reading from the store.

storePut

protected void storePut(int location,
                        java.nio.ByteBuffer b)
                 throws java.io.IOException

Puts data at the given location from the given ByteBuffer.

Specified by:

storePut in class AbstractStore

Parameters:

location - The offset to put the data, in bytes, from the beginning of the store.

b - The buffer to take the data from. The buffer will be emptied of data to its limit (so it has no remaining bytes).

Throws:

java.io.IOException - An error occurred writing to the store.