jdbm.recman

Class PageManager

java.lang.Object

jdbm.recman.PageManager

final class PageManager
extends java.lang.Object

This class manages the linked lists of pages that make up a recordFile. It contains a FileHeadrer and a reference to the recordFile it manages.

Field Summary

Fields

Modifier and Type	Field and Description
private FileHeader	header header data
private BlockIo	headerBuf recordFile header containing block
private RecordFile	recordFile our record recordFile

Constructor Summary

Constructors

Constructor and Description
PageManager(RecordFile recordFile) Creates a new page manager using the indicated record recordFile.

Method Summary

Modifier and Type	Method and Description
(package private) long	allocate(short type) Allocates a page of the indicated type.
(package private) void	close() Closes the page manager.
(package private) void	commit() Commit all pending (in-memory) data by flushing the page manager.
(package private) void	free(short type, long recid) Frees a page of the indicated type.
(package private) FileHeader	getFileHeader() Returns the recordFile header.
(package private) long	getFirst(short type) Returns the first page on the indicated list.
(package private) long	getLast(short type) Returns the last page on the indicated list.
(package private) long	getNext(long block) Returns the page following the indicated block
(package private) long	getPrev(long block) Returns the page before the indicated block
(package private) RecordFile	getRecordFile()
(package private) void	rollback() Flushes the page manager.

Methods inherited from class java.lang.Object

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

Field Detail

recordFile

private RecordFile recordFile

our record recordFile

header

private FileHeader header

header data

headerBuf

private BlockIo headerBuf

recordFile header containing block

Constructor Detail

PageManager

PageManager(RecordFile recordFile)
     throws java.io.IOException

Creates a new page manager using the indicated record recordFile. We will load in memory the associated FileHeader, which is read from the RecordFile if it exists, or is created if it doesn't.

Parameters:

The - associated RecordFile

Throws:

java.io.IOException - If there is an issue storing data into the recordFile

Method Detail

allocate

long allocate(short type)
       throws java.io.IOException

Allocates a page of the indicated type.

Parameters:

The - page type we want to allocate

Returns:

The record ID of the page.

Throws:

java.io.IOException

free

void free(short type,
          long recid)
   throws java.io.IOException

Frees a page of the indicated type.

Throws:

java.io.IOException

getNext

long getNext(long block)
      throws java.io.IOException

Returns the page following the indicated block

Throws:

java.io.IOException

getPrev

long getPrev(long block)
      throws java.io.IOException

Returns the page before the indicated block

Throws:

java.io.IOException

getFirst

long getFirst(short type)
       throws java.io.IOException

Returns the first page on the indicated list.

Throws:

java.io.IOException

getLast

long getLast(short type)
      throws java.io.IOException

Returns the last page on the indicated list.

Throws:

java.io.IOException

commit

void commit()
     throws java.io.IOException

Commit all pending (in-memory) data by flushing the page manager. This forces a flush of all outstanding blocks (this is an implicit RecordFile.commit() as well).

Throws:

java.io.IOException

rollback

void rollback()
       throws java.io.IOException

Flushes the page manager. This forces a flush of all outstanding blocks (this is an implicit RecordFile.commit() as well).

Throws:

java.io.IOException

close

void close()
    throws java.io.IOException

Closes the page manager. This flushes the page manager and releases the lock on the header.

Throws:

java.io.IOException

getFileHeader

FileHeader getFileHeader()

Returns the recordFile header.

getRecordFile

RecordFile getRecordFile()