UsageMap.PageCursor

java.lang.Object
- com.healthmarketscience.jackcess.impl.UsageMap.PageCursor

Enclosing class:

UsageMap
```
public final class UsageMap.PageCursor
extends java.lang.Object
```
Utility class to traverse over the pages in the UsageMap. Remains valid in the face of usage map modifications.

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`private class`	`UsageMap.PageCursor.DirHandler` Handles moving the cursor in a given direction.
`private class`	`UsageMap.PageCursor.ForwardDirHandler` Handles moving the cursor forward.
`private class`	`UsageMap.PageCursor.ReverseDirHandler` Handles moving the cursor backward.

Field Summary

Fields
Modifier and Type	Field and Description
`private int`	`_curPageNumber` the current used page number
`private UsageMap.PageCursor.DirHandler`	`_forwardDirHandler` handler for moving the page cursor forward
`private int`	`_lastModCount` the last read modification count on the UsageMap.
`private int`	`_prevPageNumber` the previous used page number
`private UsageMap.PageCursor.DirHandler`	`_reverseDirHandler` handler for moving the page cursor backward

Constructor Summary

Constructors
Modifier Constructor and Description

private PageCursor()

Constructors
Modifier	Constructor and Description
`private`	`PageCursor()`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`afterLast()` After calling this method, `getPreviousPage()` will return the last page in the map
`void`	`beforeFirst()` After calling this method, `getNextPage()` will return the first page in the map
`private void`	`checkForModification()` Checks the usage map for modifications an updates state accordingly.
`private int`	`getAnotherPage(boolean moveForward)` Gets another page in the given direction, returning the new page.
`private UsageMap.PageCursor.DirHandler`	`getDirHandler(boolean moveForward)` Returns the DirHandler for the given direction
`int`	`getNextPage()`
`int`	`getPreviousPage()`
`UsageMap`	`getUsageMap()`
`boolean`	`isUpToDate()` Returns `true` if this cursor is up-to-date with respect to its usage map.
`void`	`reset()` After calling this method, getNextPage will return the first page in the map
`protected void`	`reset(boolean moveForward)` Resets this page cursor for traversing the given direction.
`private void`	`restorePosition(int curPageNumber)` Restores a current position for the cursor (current position becomes previous position).
`protected void`	`restorePosition(int curPageNumber, int prevPageNumber)` Restores a current and previous position for the cursor.
`java.lang.String`	`toString()`
`private int`	`updatePosition(int pageNumber)`

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

- Field Detail
  - _forwardDirHandler
```
private final UsageMap.PageCursor.DirHandler _forwardDirHandler
```
    handler for moving the page cursor forward
  - _reverseDirHandler
```
private final UsageMap.PageCursor.DirHandler _reverseDirHandler
```
    handler for moving the page cursor backward
  - _curPageNumber
```
private int _curPageNumber
```
    the current used page number
  - _prevPageNumber
```
private int _prevPageNumber
```
    the previous used page number
  - _lastModCount
```
private int _lastModCount
```
    the last read modification count on the UsageMap. we track this so that the cursor can detect updates to the usage map while traversing and act accordingly
- Constructor Detail
  - PageCursor
```
private PageCursor()
```
- Method Detail
  - getUsageMap
```
public UsageMap getUsageMap()
```
  - getDirHandler
```
private UsageMap.PageCursor.DirHandler getDirHandler(boolean moveForward)
```
    Returns the DirHandler for the given direction
  - isUpToDate
```
public boolean isUpToDate()
```
    Returns true if this cursor is up-to-date with respect to its usage map.
  - getNextPage
```
public int getNextPage()
```
    Returns:
    
    valid page number if there was another page to read, RowIdImpl.LAST_PAGE_NUMBER otherwise
  - getPreviousPage
```
public int getPreviousPage()
```
    Returns:
    
    valid page number if there was another page to read, RowIdImpl.FIRST_PAGE_NUMBER otherwise
  - getAnotherPage
```
private int getAnotherPage(boolean moveForward)
```
    Gets another page in the given direction, returning the new page.
  - reset
```
public void reset()
```
    After calling this method, getNextPage will return the first page in the map
  - beforeFirst
```
public void beforeFirst()
```
    After calling this method, getNextPage() will return the first page in the map
  - afterLast
```
public void afterLast()
```
    After calling this method, getPreviousPage() will return the last page in the map
  - reset
```
protected void reset(boolean moveForward)
```
    Resets this page cursor for traversing the given direction.
  - restorePosition
```
private void restorePosition(int curPageNumber)
```
    Restores a current position for the cursor (current position becomes previous position).
  - restorePosition
```
protected void restorePosition(int curPageNumber,
                               int prevPageNumber)
```
    Restores a current and previous position for the cursor.
  - checkForModification
```
private void checkForModification()
```
    Checks the usage map for modifications an updates state accordingly.
  - updatePosition
```
private int updatePosition(int pageNumber)
```
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object

Class UsageMap.PageCursor

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

_forwardDirHandler

_reverseDirHandler

_curPageNumber

_prevPageNumber

_lastModCount

Constructor Detail

PageCursor

Method Detail

getUsageMap

getDirHandler

isUpToDate

getNextPage

getPreviousPage

getAnotherPage

reset

beforeFirst

afterLast

reset

restorePosition

restorePosition

checkForModification

updatePosition

toString