org.apache.wiki.providers

Class CachingAttachmentProvider

java.lang.Object

org.apache.wiki.providers.CachingAttachmentProvider

All Implemented Interfaces:

WikiAttachmentProvider, WikiProvider

public class CachingAttachmentProvider
extends Object
implements WikiAttachmentProvider

Provides a caching attachment provider. This class rests on top of a real provider class and provides a cache to speed things up. Only the Attachment objects are cached; the actual attachment contents are fetched always from the provider.

Since:

2.1.64.

Field Summary

Fields

Modifier and Type	Field and Description
static String	ATTCACHE_NAME Name of the attachment cache.
static String	ATTCOLLCACHE_NAME Name of the attachment cache.
static String	DIR_EXTENSION The extension to append to directory names to denote an attachment directory.
static int	m_capacity Default cache capacity for now.
static String	PROP_STORAGEDIR Property that supplies the directory used to store attachments.

Fields inherited from interface org.apache.wiki.WikiProvider

LATEST_VERSION

Constructor Summary

Constructors

Constructor and Description
CachingAttachmentProvider()

Method Summary

Modifier and Type	Method and Description
void	deleteAttachment(Attachment att) Removes an entire page from the repository.
void	deleteVersion(Attachment att) Removes a specific version from the repository.
Collection	findAttachments(QueryItem[] query) Finds attachments based on the query.
InputStream	getAttachmentData(Attachment att) Get attachment data.
Attachment	getAttachmentInfo(WikiPage page, String name, int version) Returns info about an attachment.
String	getProviderInfo() Gets the provider class name, and cache statistics (misscount and,hitcount of the attachment cache).
WikiAttachmentProvider	getRealProvider() Returns the WikiAttachmentProvider that this caching provider delegates to.
List	getVersionHistory(Attachment att) Returns version history.
void	initialize(WikiEngine engine, Properties properties) Initializes the page provider.
List	listAllChanged(Date timestamp) Lists changed attachments since given date.
Collection	listAttachments(WikiPage page) Lists all attachments attached to a page.
void	moveAttachmentsForPage(String oldParent, String newParent) Move all the attachments for a given page so that they are attached to a new page.
void	putAttachmentData(Attachment att, InputStream data) Put new attachment data.

Methods inherited from class java.lang.Object

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

Field Detail

m_capacity

public static final int m_capacity

Default cache capacity for now.

See Also:

Constant Field Values

ATTCOLLCACHE_NAME

public static final String ATTCOLLCACHE_NAME

Name of the attachment cache.

See Also:

Constant Field Values

ATTCACHE_NAME

public static final String ATTCACHE_NAME

Name of the attachment cache.

See Also:

Constant Field Values

DIR_EXTENSION

public static final String DIR_EXTENSION

The extension to append to directory names to denote an attachment directory.

See Also:

Constant Field Values

PROP_STORAGEDIR

public static final String PROP_STORAGEDIR

Property that supplies the directory used to store attachments.

See Also:

Constant Field Values

Constructor Detail

CachingAttachmentProvider

public CachingAttachmentProvider()

Method Detail

initialize

public void initialize(WikiEngine engine,
                       Properties properties)
                throws NoRequiredPropertyException,
                       IOException

Initializes the page provider.

Specified by:

initialize in interface WikiProvider

Parameters:

engine - WikiEngine to own this provider

properties - A set of properties used to initialize this provider

Throws:

NoRequiredPropertyException - If the provider needs a property which is not found in the property set

IOException - If there is an IO problem

putAttachmentData

public void putAttachmentData(Attachment att,
                              InputStream data)
                       throws ProviderException,
                              IOException

Put new attachment data.

Specified by:

putAttachmentData in interface WikiAttachmentProvider

Parameters:

att - Attachment object to add new data to

data - The stream from which the provider should read the data

Throws:

ProviderException - If there are other errors.

IOException - If writing fails

getAttachmentData

public InputStream getAttachmentData(Attachment att)
                              throws ProviderException,
                                     IOException

Get attachment data.

Specified by:

getAttachmentData in interface WikiAttachmentProvider

Parameters:

att - The attachment

Returns:

An InputStream which you contains the raw data of the object. It's your responsibility to close it.

Throws:

ProviderException - If the attachment cannot be found

IOException - If the attachment cannot be opened

listAttachments

public Collection listAttachments(WikiPage page)
                           throws ProviderException

Lists all attachments attached to a page.

Specified by:

listAttachments in interface WikiAttachmentProvider

Parameters:

page - The page to list the attachments from.

Returns:

A collection of Attachment objects. May be empty, but never null.

Throws:

ProviderException - If something goes wrong when listing the attachments.

findAttachments

public Collection findAttachments(QueryItem[] query)

Finds attachments based on the query.

Specified by:

findAttachments in interface WikiAttachmentProvider

Parameters:

query - An array of QueryItem objects to search for

Returns:

A Collection of Attachment objects. May be empty, but never null.

listAllChanged

public List listAllChanged(Date timestamp)
                    throws ProviderException

Lists changed attachments since given date. Can also be used to fetch a list of all pages.

This is different from WikiPageProvider, where you basically get a list of all pages, then sort them locally. However, since some providers can be more efficient in locating recently changed files (like any database) than our non-optimized Java code, it makes more sense to fetch the whole list this way.

To get all files, call this with Date(0L);

Specified by:

listAllChanged in interface WikiAttachmentProvider

Parameters:

timestamp - List all files from this date onward.

Returns:

A List of Attachment objects, in most-recently-changed first order.

Throws:

ProviderException - If something goes wrong.

getAttachmentInfo

public Attachment getAttachmentInfo(WikiPage page,
                                    String name,
                                    int version)
                             throws ProviderException

Returns info about an attachment.

Specified by:

getAttachmentInfo in interface WikiAttachmentProvider

Parameters:

page - The parent page

name - The name of the attachment

version - The version of the attachment (it's okay to use WikiPage.LATEST_VERSION to find the latest one)

Returns:

An attachment object

Throws:

ProviderException - If the attachment cannot be found or some other error occurs.

getVersionHistory

public List getVersionHistory(Attachment att)

Returns version history. Each element should be an Attachment.

Specified by:

getVersionHistory in interface WikiAttachmentProvider

Parameters:

att - The attachment for which to find the version history for.

Returns:

A List of Attachment objects.

deleteVersion

public void deleteVersion(Attachment att)
                   throws ProviderException

Removes a specific version from the repository. The implementations should really do no more security checks, since that is the domain of the AttachmentManager. Just delete it as efficiently as you can.

Specified by:

deleteVersion in interface WikiAttachmentProvider

Parameters:

att - Attachment to be removed. The version field is checked, and thus only that version is removed.

Throws:

ProviderException - If the attachment cannot be removed for some reason.

deleteAttachment

public void deleteAttachment(Attachment att)
                      throws ProviderException

Removes an entire page from the repository. The implementations should really do no more security checks, since that is the domain of the AttachmentManager. Just delete it as efficiently as you can. You should also delete any auxiliary files and directories that belong to this attachment, IF they were created by this provider.

Specified by:

deleteAttachment in interface WikiAttachmentProvider

Parameters:

att - Attachment to delete.

Throws:

ProviderException - If the page could not be removed for some reason.

getProviderInfo

public String getProviderInfo()

Gets the provider class name, and cache statistics (misscount and,hitcount of the attachment cache).

Specified by:

getProviderInfo in interface WikiProvider

Returns:

A plain string with all the above mentioned values.

getRealProvider

public WikiAttachmentProvider getRealProvider()

Returns the WikiAttachmentProvider that this caching provider delegates to.

Returns:

The real provider underneath this one.

moveAttachmentsForPage

public void moveAttachmentsForPage(String oldParent,
                                   String newParent)
                            throws ProviderException

Move all the attachments for a given page so that they are attached to a new page.

Specified by:

moveAttachmentsForPage in interface WikiAttachmentProvider

Parameters:

oldParent - Name of the page we are to move the attachments from.

newParent - Name of the page we are to move the attachments to.

Throws:

ProviderException - If the attachments could not be moved for some reason.