SqlJetPageCache

java.lang.Object
- org.tmatesoft.sqljet.core.internal.pager.SqlJetPageCache

All Implemented Interfaces:

ISqlJetPageCache
```
public class SqlJetPageCache
extends java.lang.Object
implements ISqlJetPageCache
```
A complete page cache is an instance of this structure.

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`PAGE_CACHE_SIZE_DEFAULT`
`static int`	`PAGE_CACHE_SIZE_MINIMUM`
`static java.lang.String`	`SQLJET_PAGE_CACHE_SIZE` System property name for cache size configuration.

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`cleanAll()` Mark all dirty list pages as clean Make every page in the cache clean.
`void`	`clear()` Discard the contents of the cache
`void`	`clearSyncFlags()` Clear flags from pages of the page cache
`void`	`close()` Reset and close the cache object
`void`	`drop(ISqlJetPage page)` Remove page from cache Drop a page from the cache.
`ISqlJetPage`	`fetch(int pgno, boolean createFlag)` Try to obtain a page from the cache.
`int`	`getCachesize()` Get the cache-size for the pager-cache.
`ISqlJetPage`	`getDirtyList()` Get a list of all dirty pages in the cache, sorted by page number
`int`	`getPageCount()` Return the total number of pages stored in the cache
`int`	`getRefCount()` Return the total number of outstanding page references
`void`	`iterate(ISqlJetPageCallback iter)` Iterate through all pages currently stored in the cache.
`void`	`makeClean(ISqlJetPage page)` Make sure the page is marked as clean.
`void`	`makeDirty(ISqlJetPage page)` Make sure the page is marked as dirty.
`void`	`move(ISqlJetPage page, int newPgno)` Change a page number.
`void`	`open(int szPage, boolean purgeable, ISqlJetPageCallback stress)` Create a new pager cache.
`void`	`release(ISqlJetPage page)` Dereference a page.
`void`	`setCacheSize(int mxPage)` Set the suggested cache-size for the pager-cache.
`void`	`setPageSize(int pageSize)` Modify the page-size after the cache has been created.
`void`	`truncate(int pgno)` Remove all pages with page numbers more than pageNumber.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - SQLJET_PAGE_CACHE_SIZE
```
public static final java.lang.String SQLJET_PAGE_CACHE_SIZE
```
    System property name for cache size configuration.
    
    See Also:
    Constant Field Values
  - PAGE_CACHE_SIZE_DEFAULT
```
public static final int PAGE_CACHE_SIZE_DEFAULT
```
    See Also:
    Constant Field Values
  - PAGE_CACHE_SIZE_MINIMUM
```
public static final int PAGE_CACHE_SIZE_MINIMUM
```
    See Also:
    Constant Field Values
- Method Detail
  - open
```
public void open(int szPage,
        boolean purgeable,
        ISqlJetPageCallback stress)
```
    Description copied from interface: ISqlJetPageCache
    
    Create a new pager cache. Under memory stress, invoke xStress to try to make pages clean. Only clean and unpinned pages can be reclaimed.
    
    Specified by:
    
    open in interface ISqlJetPageCache
    
    Parameters:
    szPage - Size of every page
    purgeable - True if pages are on backing store
    stress - Call to try to make pages clean
  - setPageSize
```
public void setPageSize(int pageSize)
```
    Description copied from interface: ISqlJetPageCache
    
    Modify the page-size after the cache has been created. Change the page size for PCache object. This can only happen when the cache is empty.
    
    Specified by:
    
    setPageSize in interface ISqlJetPageCache
  - fetch
```
public ISqlJetPage fetch(int pgno,
                boolean createFlag)
                  throws SqlJetException
```
    Description copied from interface: ISqlJetPageCache
    
    Try to obtain a page from the cache.
    
    Specified by:
    
    fetch in interface ISqlJetPageCache
    
    createFlag - If true, create page if it does not exist already
    
    Returns:
    
    Throws:
    
    SqlJetException
  - release
```
public void release(ISqlJetPage page)
```
    Description copied from interface: ISqlJetPageCache
    
    Dereference a page. When the reference count reaches zero, move the page to the LRU list if it is clean. One release per successful fetch. Page is pinned until released. Reference counted.
    
    Specified by:
    
    release in interface ISqlJetPageCache
  - drop
```
public void drop(ISqlJetPage page)
```
    Description copied from interface: ISqlJetPageCache
    
    Remove page from cache Drop a page from the cache. There must be exactly one reference to the page. This function deletes that reference, so after it returns the page pointed to by p is invalid.
    
    Specified by:
    
    drop in interface ISqlJetPageCache
  - makeDirty
```
public void makeDirty(ISqlJetPage page)
```
    Description copied from interface: ISqlJetPageCache
    
    Make sure the page is marked as dirty. If it isn't dirty already, make it so.
    
    Specified by:
    
    makeDirty in interface ISqlJetPageCache
  - makeClean
```
public void makeClean(ISqlJetPage page)
```
    Description copied from interface: ISqlJetPageCache
    
    Make sure the page is marked as clean. If it isn't clean already, make it so.
    
    Specified by:
    
    makeClean in interface ISqlJetPageCache
  - cleanAll
```
public void cleanAll()
```
    Description copied from interface: ISqlJetPageCache
    
    Mark all dirty list pages as clean Make every page in the cache clean.
    
    Specified by:
    
    cleanAll in interface ISqlJetPageCache
  - clearSyncFlags
```
public void clearSyncFlags()
```
    Description copied from interface: ISqlJetPageCache
    
    Clear flags from pages of the page cache
    
    Specified by:
    
    clearSyncFlags in interface ISqlJetPageCache
  - move
```
public void move(ISqlJetPage page,
        int newPgno)
```
    Description copied from interface: ISqlJetPageCache
    
    Change a page number. Used by incr-vacuum. Change the page number of page p to newPgno. If newPgno is 0, then the page object is added to the clean-list and the PGHDR_REUSE_UNLIKELY flag set.
    
    Specified by:
    
    move in interface ISqlJetPageCache
  - truncate
```
public void truncate(int pgno)
```
    Description copied from interface: ISqlJetPageCache
    
    Remove all pages with page numbers more than pageNumber. Reset the cache if pageNumber==0 Drop every cache entry whose page number is greater than "pgno".
    
    Specified by:
    
    truncate in interface ISqlJetPageCache
  - close
```
public void close()
```
    Description copied from interface: ISqlJetPageCache
    
    Reset and close the cache object
    
    Specified by:
    
    close in interface ISqlJetPageCache
  - clear
```
public void clear()
```
    Description copied from interface: ISqlJetPageCache
    
    Discard the contents of the cache
    
    Specified by:
    
    clear in interface ISqlJetPageCache
  - getDirtyList
```
public ISqlJetPage getDirtyList()
```
    Description copied from interface: ISqlJetPageCache
    
    Get a list of all dirty pages in the cache, sorted by page number
    
    Specified by:
    
    getDirtyList in interface ISqlJetPageCache
    
    Returns:
  - getRefCount
```
public int getRefCount()
```
    Description copied from interface: ISqlJetPageCache
    
    Return the total number of outstanding page references
    
    Specified by:
    
    getRefCount in interface ISqlJetPageCache
  - getPageCount
```
public int getPageCount()
```
    Description copied from interface: ISqlJetPageCache
    
    Return the total number of pages stored in the cache
    
    Specified by:
    
    getPageCount in interface ISqlJetPageCache
  - getCachesize
```
public int getCachesize()
```
    Description copied from interface: ISqlJetPageCache
    
    Get the cache-size for the pager-cache.
    
    Specified by:
    
    getCachesize in interface ISqlJetPageCache
    
    Returns:
  - setCacheSize
```
public void setCacheSize(int mxPage)
```
    Description copied from interface: ISqlJetPageCache
    
    Set the suggested cache-size for the pager-cache. If no global maximum is configured, then the system attempts to limit the total number of pages cached by purgeable pager-caches to the sum of the suggested cache-sizes.
    
    Specified by:
    
    setCacheSize in interface ISqlJetPageCache
  - iterate
```
public void iterate(ISqlJetPageCallback iter)
             throws SqlJetException
```
    Description copied from interface: ISqlJetPageCache
    
    Iterate through all pages currently stored in the cache.
    
    Specified by:
    
    iterate in interface ISqlJetPageCache
    
    Throws:
    
    SqlJetException

Class SqlJetPageCache

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

SQLJET_PAGE_CACHE_SIZE

PAGE_CACHE_SIZE_DEFAULT

PAGE_CACHE_SIZE_MINIMUM

Method Detail

open

setPageSize

fetch

release

drop

makeDirty

makeClean

cleanAll

clearSyncFlags

move

truncate

close

clear

getDirtyList

getRefCount

getPageCount

getCachesize

setCacheSize

iterate