org.fusesource.hawtdb.internal.page

Class HawtPageFile

java.lang.Object

org.fusesource.hawtdb.internal.page.HawtPageFile

All Implemented Interfaces:

Paged, PageFile

public class HawtPageFile
extends Object
implements PageFile

Provides a PageFile interface to a MemoryMappedFile.

Author:

Hiram Chirino

Nested Class Summary

Nested classes/interfaces inherited from interface org.fusesource.hawtdb.api.Paged

Paged.SliceType

Field Summary

Fields

Modifier and Type	Field and Description
boolean	storeFreePages

Constructor Summary

Constructors

Constructor and Description
HawtPageFile(MemoryMappedFile file, short pageSize, int headerSize, int maxPages, boolean storeFreePages)

Method Summary

Modifier and Type	Method and Description
int	alloc() does the same as allocator().alloc(1)
SimpleAllocator	allocator()
<T> void	clear(PagedAccessor<T> pagedAccessor, int page) Frees any pages associated with the value stored at the given page if any.
void	close()
void	flush()
void	free(int page) does the same as allocator().free(page, 1)
<T> T	get(PagedAccessor<T> pagedAccessor, int page) Gets an object previously put at the given page.
MemoryMappedFile	getFile()
int	getHeaderSize()
int	getPageSize()
long	offset(long pageId)
int	pages(int length)
<T> void	put(PagedAccessor<T> pagedAccessor, int page, T value) Put an object at a given page.
void	read(int pageId, org.fusesource.hawtbuf.Buffer buffer) Copies the contents of a page into the buffer space.
ByteBuffer	slice(Paged.SliceType type, int pageId, int size) Provides direct access to the memory associated with a page.
String	toString()
void	unslice(ByteBuffer buffer)
void	write(int pageId, org.fusesource.hawtbuf.Buffer buffer) Copies the buffer into the page.
void	write(int pageId, ByteBuffer buffer) Writes a byte buffer to a page location.

Methods inherited from class java.lang.Object

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

Field Detail

storeFreePages

public final boolean storeFreePages

Constructor Detail

HawtPageFile

public HawtPageFile(MemoryMappedFile file,
                    short pageSize,
                    int headerSize,
                    int maxPages,
                    boolean storeFreePages)
             throws IOException

Throws:

IOException

Method Detail

close

public void close()
           throws IOException

Throws:

IOException

allocator

public SimpleAllocator allocator()

Specified by:

allocator in interface Paged

Returns:

An object which provides access to allocate/deallocate pages.

alloc

public int alloc()

Description copied from interface: Paged

does the same as allocator().alloc(1)

Specified by:

alloc in interface Paged

Returns:

a newly allocated page location.

free

public void free(int page)

Description copied from interface: Paged

does the same as allocator().free(page, 1)

Specified by:

free in interface Paged

read

public void read(int pageId,
                 org.fusesource.hawtbuf.Buffer buffer)

Description copied from interface: Paged

Copies the contents of a page into the buffer space. The buffer offset will be updated to reflect the amount of data copied into the buffer.

Specified by:

read in interface Paged

write

public void write(int pageId,
                  org.fusesource.hawtbuf.Buffer buffer)

Description copied from interface: Paged

Copies the buffer into the page. The buffer offset will be updated to reflect the amount of data copied to the page.

Specified by:

write in interface Paged

slice

public ByteBuffer slice(Paged.SliceType type,
                        int pageId,
                        int size)

Description copied from interface: Paged

Provides direct access to the memory associated with a page. Specifying the correct mode argument is especially critical and the Paged resources is being accessed in a transaction context so that the transaction can maintain snapshot isolation.

Specified by:

slice in interface Paged

Parameters:

type - how will the buffer be used.

pageId - the starting page of the buffer

size - the number of pages to include in the buffer.

Returns:

unslice

public void unslice(ByteBuffer buffer)

Specified by:

unslice in interface Paged

getPageSize

public int getPageSize()

Specified by:

getPageSize in interface Paged

Returns:

the maximum number of bytes that be read or written to a page.

pages

public int pages(int length)

Specified by:

pages in interface Paged

Returns:

the number of pages that would be required to store the specified number of bytes

flush

public void flush()

Specified by:

flush in interface Paged

get

public <T> T get(PagedAccessor<T> pagedAccessor,
                 int page)

Description copied from interface: Paged

Gets an object previously put at the given page. The returned object SHOULD NEVER be mutated.

Specified by:

get in interface Paged

Returns:

put

public <T> void put(PagedAccessor<T> pagedAccessor,
                    int page,
                    T value)

Description copied from interface: Paged

Put an object at a given page. The supplied object SHOULD NEVER be mutated once it has been stored.

Specified by:

put in interface Paged

clear

public <T> void clear(PagedAccessor<T> pagedAccessor,
                      int page)

Description copied from interface: Paged

Frees any pages associated with the value stored at the given page if any. Does not free the page supplied.

Specified by:

clear in interface Paged

write

public void write(int pageId,
                  ByteBuffer buffer)

Description copied from interface: PageFile

Writes a byte buffer to a page location.

Specified by:

write in interface PageFile

Parameters:

pageId - the location to write to

buffer - the buffer containing the data to write.

offset

public long offset(long pageId)

getHeaderSize

public int getHeaderSize()

getFile

public MemoryMappedFile getFile()

toString

public String toString()

Overrides:

toString in class Object