alluxio.client.file.cache

Interface PageStore

All Superinterfaces:

AutoCloseable

All Known Implementing Classes:

LocalPageStore, RocksPageStore

public interface PageStore
extends AutoCloseable

A simple abstraction on the storage to put, get and delete pages. The implementation of this class does not need to provide thread-safety.

Field Summary

Fields

Modifier and Type	Field and Description
static org.slf4j.Logger	LOG

Method Summary

Modifier and Type	Method and Description
static PageStore	create(PageStoreOptions options, boolean init) Creates a PageStore.
void	delete(PageId pageId, long pageSize) Deletes a page from the store.
default ReadableByteChannel	get(PageId pageId) Wraps a page from the store as a channel to read.
ReadableByteChannel	get(PageId pageId, int pageOffset) Gets part of a page from the store to the destination channel.
long	getCacheSize()
java.util.stream.Stream<PageInfo>	getPages() Gets a stream of all pages from the page store.
static Path	getStorePath(PageStoreType storeType, String rootDir) Gets store path given root directory and store type.
static void	initialize(PageStoreOptions options) Initializes a page store at the configured location.
void	put(PageId pageId, byte[] page) Writes a new page from a source channel to the store.

Methods inherited from interface java.lang.AutoCloseable

close

Field Detail

LOG

static final org.slf4j.Logger LOG

Method Detail

create

static PageStore create(PageStoreOptions options,
                        boolean init)
                 throws IOException

Creates a PageStore. When init is false, restore from previous state; clean up the cache dir otherwise.

Parameters:

options - the options to instantiate the page store

init - whether to init the cache dir

Returns:

a PageStore instance

Throws:

IOException - if I/O error happens

getStorePath

static Path getStorePath(PageStoreType storeType,
                         String rootDir)

Gets store path given root directory and store type.

Parameters:

storeType - the type of the page store

rootDir - the root directory path

Returns:

the store directory path

initialize

static void initialize(PageStoreOptions options)
                throws IOException

Initializes a page store at the configured location. Data from different store type will be removed.

Parameters:

options - initialize a new page store based on the options

Throws:

IOException - when failed to clean up the specific location

put

void put(PageId pageId,
         byte[] page)
  throws IOException

Writes a new page from a source channel to the store.

Parameters:

pageId - page identifier

page - page data

Throws:

IOException

get

default ReadableByteChannel get(PageId pageId)
                         throws IOException,
                                PageNotFoundException

Wraps a page from the store as a channel to read.

Parameters:

pageId - page identifier

Returns:

the channel to read this page

Throws:

IOException - when the store fails to read this page

PageNotFoundException - when the page isn't found in the store

get

ReadableByteChannel get(PageId pageId,
                        int pageOffset)
                 throws IOException,
                        PageNotFoundException

Gets part of a page from the store to the destination channel.

Parameters:

pageId - page identifier

pageOffset - offset within page

Returns:

the number of bytes read

Throws:

IOException - when the store fails to read this page

PageNotFoundException - when the page isn't found in the store

IllegalArgumentException - when the page offset exceeds the page size

delete

void delete(PageId pageId,
            long pageSize)
     throws IOException,
            PageNotFoundException

Deletes a page from the store.

Parameters:

pageId - page identifier

pageSize - page size in bytes

Throws:

IOException - when the store fails to delete this page

PageNotFoundException - when the page isn't found in the store

getPages

java.util.stream.Stream<PageInfo> getPages()
                                    throws IOException

Gets a stream of all pages from the page store. This stream needs to be closed as it may open IO resources.

Returns:

a stream of all pages from page store

Throws:

IOException - if any error occurs

getCacheSize

long getCacheSize()

Returns:

an estimated cache size in bytes