java.lang.Object
- org.apache.derby.impl.store.raw.data.AllocExtent

All Implemented Interfaces:

java.io.Externalizable, java.io.Serializable
```
public class AllocExtent
extends java.lang.Object
implements java.io.Externalizable
```
An allocation extent row manages the page status of page in the extent. AllocExtent is externalizable and is written to the AllocPage directly, without being converted to a row first.
See Also:

AllocPage, Serialized Form

Field Summary

Fields
Modifier and Type	Field	Description
`private static int`	`ALL_FREE`
`protected static int`	`ALLOCATED_PAGE`	public Per Page status
`protected static int`	`DEALLOCATED_PAGE`
`private long`	`extentEnd`
`private int`	`extentLength`
`private long`	`extentOffset`
`private long`	`extentStart`
`(package private) int`	`extentStatus`
`protected static int`	`FREE_PAGE`
`(package private) FormatableBitSet`	`freePages`
`private static int`	`HAS_DEALLOCATED`
`private static int`	`HAS_FREE`
`private static int`	`HAS_UNFILLED_PAGES`
`private static int`	`KEEP_UNFILLED_PAGES`
`private static int`	`NO_DEALLOC_PAGE_MAP`
`private int`	`preAllocLength`
`private int`	`reserved1`
`private long`	`reserved2`
`private long`	`reserved3`
`private static int`	`RETIRED`
`(package private) FormatableBitSet`	`unFilledPages`

Constructor Summary

Constructors
Modifier	Constructor	Description
	`AllocExtent()`
`protected`	`AllocExtent(long offset, long start, int length, int pagesize, int maxlength)`
`protected`	`AllocExtent(AllocExtent original)`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`protected void`	`allocPage(long pagenum)`	Allocate this page - this is called underneath the log record
`protected boolean`	`canAddFreePage(long lastAllocatedPage)`
`private void`	`checkInRange(long pagenum)`
`protected int`	`compress(BaseContainerHandle owner, RawTransaction ntt, AllocPage alloc_page)`	Compress free pages at end of this extent.
`protected void`	`compressPages(int new_highest_page, int num_pages_truncated)`
`protected void`	`deallocPage(long pagenum)`	Deallocate logical page pagenum - this is called underneath the log record.
`protected int`	`getAllocatedPageCount()`	Get the number of used page in this extent
`protected long`	`getExtentEnd()`
`protected long`	`getFirstPagenum()`	Get the first logical page number managed by this extent.
`protected long`	`getFreePageNumber(long pnum)`	Get a page number that is free
`protected long`	`getLastPagenum()`	Get the last logical page number managed by this extent.
`protected long`	`getLastPreallocPagenum()`	get the last preallocated pagenumber managed by this alloc page
`protected long`	`getLastValidPageNumber()`
`protected long`	`getNextValidPageNumber(long prevPageNumber)`
`protected long`	`getPagenum(int bit_pos)`	translate bit position in map to page number.
`protected long`	`getPageOffset(long pagenum, int pagesize, boolean deallocOK)`	Get the physical offset of pagenum.
`protected int`	`getPageStatus(long pagenum)`	Return the status of a particular page
`protected int`	`getTotalPageCount()`	Get the total number of pages in this extent
`protected int`	`getUnfilledPageCount()`	Get the number of unfilled pages in this extent
`protected long`	`getUnfilledPageNumber(long pagenum)`	Get a page number that is unfilled, pagenum is the last page that was rejected.
`protected boolean`	`isRetired()`	Return the status of this extent
`protected static int`	`MAX_RANGE(int availspace)`	Statically calculates how many pages this extent can manage given the availspace number of bytes to store this extent in if read/writeExternal changes, this must change too
`private boolean`	`mayHaveFreePage()`
`void`	`readExternal(java.io.ObjectInput in)`
`private void`	`setExtentFreePageStatus(boolean hasFree)`
`protected void`	`setLastPreallocPagenum(long preAllocPagenum)`	preallocated N pages, passed in the last preallocated page number.
`protected java.lang.String`	`toDebugString()`
`protected boolean`	`trackUnfilledPage(long pagenumber, boolean unfilled)`
`protected void`	`undoCompressPages(int new_highest_page, int num_pages_truncated)`	Undo the compress space operation.
`protected void`	`updateUnfilledPageInfo(AllocExtent inputExtent)`
`void`	`writeExternal(java.io.ObjectOutput out)`

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

- Field Detail
  - extentOffset
```
private long extentOffset
```
  - extentStart
```
private long extentStart
```
  - extentEnd
```
private long extentEnd
```
  - extentLength
```
private int extentLength
```
  - extentStatus
```
int extentStatus
```
  - preAllocLength
```
private int preAllocLength
```
  - reserved1
```
private int reserved1
```
  - reserved2
```
private long reserved2
```
  - reserved3
```
private long reserved3
```
  - HAS_DEALLOCATED
```
private static final int HAS_DEALLOCATED
```
    See Also:
    
    Constant Field Values
  - HAS_FREE
```
private static final int HAS_FREE
```
    See Also:
    
    Constant Field Values
  - ALL_FREE
```
private static final int ALL_FREE
```
    See Also:
    
    Constant Field Values
  - HAS_UNFILLED_PAGES
```
private static final int HAS_UNFILLED_PAGES
```
    See Also:
    
    Constant Field Values
  - KEEP_UNFILLED_PAGES
```
private static final int KEEP_UNFILLED_PAGES
```
    See Also:
    
    Constant Field Values
  - NO_DEALLOC_PAGE_MAP
```
private static final int NO_DEALLOC_PAGE_MAP
```
    See Also:
    
    Constant Field Values
  - RETIRED
```
private static final int RETIRED
```
    See Also:
    
    Constant Field Values
  - ALLOCATED_PAGE
```
protected static final int ALLOCATED_PAGE
```
    public Per Page status
    
    See Also:
    
    Constant Field Values
  - DEALLOCATED_PAGE
```
protected static final int DEALLOCATED_PAGE
```
    See Also:
    
    Constant Field Values
  - FREE_PAGE
```
protected static final int FREE_PAGE
```
    See Also:
    
    Constant Field Values
  - freePages
```
FormatableBitSet freePages
```
  - unFilledPages
```
FormatableBitSet unFilledPages
```
- Constructor Detail
  - AllocExtent
```
protected AllocExtent(long offset,
                      long start,
                      int length,
                      int pagesize,
                      int maxlength)
```
  - AllocExtent
```
protected AllocExtent(AllocExtent original)
```
  - AllocExtent
```
public AllocExtent()
```
- Method Detail
  - MAX_RANGE
```
protected static int MAX_RANGE(int availspace)
```
    Statically calculates how many pages this extent can manage given the availspace number of bytes to store this extent in if read/writeExternal changes, this must change too
  - writeExternal
```
public void writeExternal(java.io.ObjectOutput out)
                   throws java.io.IOException
```
    Specified by:
    
    writeExternal in interface java.io.Externalizable
    
    Throws:
    
    java.io.IOException
  - readExternal
```
public void readExternal(java.io.ObjectInput in)
                  throws java.io.IOException,
                         java.lang.ClassNotFoundException
```
    Specified by:
    
    readExternal in interface java.io.Externalizable
    
    Throws:
    
    java.io.IOException
    
    java.lang.ClassNotFoundException
  - allocPage
```
protected void allocPage(long pagenum)
                  throws StandardException
```
    Allocate this page - this is called underneath the log record
    
    Throws:
    
    StandardException - Standard Derby error policy
  - deallocPage
```
protected void deallocPage(long pagenum)
                    throws StandardException
```
    Deallocate logical page pagenum - this is called underneath the log record. pagenum must be a page managed by this extent and it must be valid
    
    Throws:
    
    StandardException - Standard Derby error policy
  - compress
```
protected int compress(BaseContainerHandle owner,
                       RawTransaction ntt,
                       AllocPage alloc_page)
                throws StandardException
```
    Compress free pages at end of this extent.
    Search backward from end of extent and prepare data structures to return pages at end of extent to the OS. Returns the lowest page that can be returned to the OS.
    
    Returns:
    
    Return bit of page where all pages that follow can be returned to the OS.
    
    Throws:
    
    StandardException
  - compressPages
```
protected void compressPages(int new_highest_page,
                             int num_pages_truncated)
```
  - undoCompressPages
```
protected void undoCompressPages(int new_highest_page,
                                 int num_pages_truncated)
```
    Undo the compress space operation.
    Undo of this operation doesn't really "undo" the operation, it just makes sure the data structures are ok after the undo. We are guaranteed at the point of the transaction doing the Undo of the compress space operation fixes up the bit maps to only point at pages within the new_highest_page range.
    Prior to logging the compress space operation all pages greater than There are only 2 possibilities at this point: 1) the truncate of pages greater than new_highest_page happened before the abort took place. W 2)
  - getExtentEnd
```
protected long getExtentEnd()
```
  - getFreePageNumber
```
protected long getFreePageNumber(long pnum)
```
    Get a page number that is free
  - getPageOffset
```
protected long getPageOffset(long pagenum,
                             int pagesize,
                             boolean deallocOK)
                      throws StandardException
```
    Get the physical offset of pagenum. If deallocOK is true, then even if pagenum is deallocated, it is OK. If deallocOK is false, then an exception is thrown if pagenum is deallocated. An exception is always thrown if pagenum is a free page
    
    Throws:
    
    StandardException - Standard Derby error policy
  - isRetired
```
protected boolean isRetired()
```
    Return the status of this extent
  - mayHaveFreePage
```
private boolean mayHaveFreePage()
```
  - setExtentFreePageStatus
```
private void setExtentFreePageStatus(boolean hasFree)
```
  - canAddFreePage
```
protected boolean canAddFreePage(long lastAllocatedPage)
```
  - getPageStatus
```
protected int getPageStatus(long pagenum)
```
    Return the status of a particular page
  - getFirstPagenum
```
protected long getFirstPagenum()
```
    Get the first logical page number managed by this extent.
  - getLastPagenum
```
protected long getLastPagenum()
```
    Get the last logical page number managed by this extent.
  - getPagenum
```
protected long getPagenum(int bit_pos)
```
    translate bit position in map to page number.
    
    Returns:
    
    The page number of this "bit" in the extent map.
  - getLastPreallocPagenum
```
protected long getLastPreallocPagenum()
```
    get the last preallocated pagenumber managed by this alloc page
  - setLastPreallocPagenum
```
protected void setLastPreallocPagenum(long preAllocPagenum)
```
    preallocated N pages, passed in the last preallocated page number.
  - getNextValidPageNumber
```
protected long getNextValidPageNumber(long prevPageNumber)
```
  - getLastValidPageNumber
```
protected long getLastValidPageNumber()
```
  - checkInRange
```
private void checkInRange(long pagenum)
```
  - updateUnfilledPageInfo
```
protected void updateUnfilledPageInfo(AllocExtent inputExtent)
```
  - trackUnfilledPage
```
protected boolean trackUnfilledPage(long pagenumber,
                                    boolean unfilled)
```
  - getUnfilledPageNumber
```
protected long getUnfilledPageNumber(long pagenum)
```
    Get a page number that is unfilled, pagenum is the last page that was rejected.
  - getAllocatedPageCount
```
protected int getAllocatedPageCount()
```
    Get the number of used page in this extent
  - getUnfilledPageCount
```
protected int getUnfilledPageCount()
```
    Get the number of unfilled pages in this extent
  - getTotalPageCount
```
protected int getTotalPageCount()
```
    Get the total number of pages in this extent
  - toDebugString
```
protected java.lang.String toDebugString()
```

Class AllocExtent

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

extentOffset

extentStart

extentEnd

extentLength

extentStatus

preAllocLength

reserved1

reserved2

reserved3

HAS_DEALLOCATED

HAS_FREE

ALL_FREE

HAS_UNFILLED_PAGES

KEEP_UNFILLED_PAGES

NO_DEALLOC_PAGE_MAP

RETIRED

ALLOCATED_PAGE

DEALLOCATED_PAGE

FREE_PAGE

freePages

unFilledPages

Constructor Detail

AllocExtent

AllocExtent

AllocExtent

Method Detail

MAX_RANGE

writeExternal

readExternal

allocPage

deallocPage

compress

compressPages

undoCompressPages

getExtentEnd

getFreePageNumber

getPageOffset

isRetired

mayHaveFreePage

setExtentFreePageStatus

canAddFreePage

getPageStatus

getFirstPagenum

getLastPagenum

getPagenum

getLastPreallocPagenum

setLastPreallocPagenum

getNextValidPageNumber

getLastValidPageNumber

checkInRange

updateUnfilledPageInfo

trackUnfilledPage

getUnfilledPageNumber

getAllocatedPageCount

getUnfilledPageCount

getTotalPageCount

toDebugString