Package org.apache.wiki.providers

Class CachingAttachmentProvider

  • All Implemented Interfaces:
    AttachmentProvider, WikiProvider
    public class CachingAttachmentProvider
extends java.lang.Object
implements AttachmentProvider
    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.

    • Method Detail

      • initialize

        public void initialize​(Engine engine,
                       java.util.Properties properties)
                throws NoRequiredPropertyException,
                       java.io.IOException
        Initializes the page provider.
        Specified by:
        initialize in interface WikiProvider
        Parameters:
        engine - Engine 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
        java.io.IOException - If there is an IO problem

      • getAttachmentData

        public java.io.InputStream getAttachmentData​(Attachment att)
                                      throws ProviderException,
                                             java.io.IOException
        Get attachment data.
        Specified by:
        getAttachmentData in interface AttachmentProvider
        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
        java.io.IOException - If the attachment cannot be opened

      • findAttachments

        public java.util.Collection<Attachment> findAttachments​(QueryItem[] query)
        Finds attachments based on the query.
        Specified by:
        findAttachments in interface AttachmentProvider
        Parameters:
        query - An array of QueryItem objects to search for
        Returns:
        A Collection of Attachment objects. May be empty, but never null.

      • listAllChanged

        public java.util.List<Attachment> listAllChanged​(java.util.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 AttachmentProvider
        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​(Page page,
                                    java.lang.String name,
                                    int version)
                             throws ProviderException
        Returns info about an attachment.
        Specified by:
        getAttachmentInfo in interface AttachmentProvider
        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.

      • 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 AttachmentProvider
        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 AttachmentProvider
        Parameters:
        att - Attachment to delete.
        Throws:
        ProviderException - If the page could not be removed for some reason.

      • getProviderInfo

        public java.lang.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 AttachmentProvider getRealProvider()
        Returns the WikiAttachmentProvider that this caching provider delegates to.
        Returns:
        The real provider underneath this one.

      • moveAttachmentsForPage

        public void moveAttachmentsForPage​(java.lang.String oldParent,
                                   java.lang.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 AttachmentProvider
        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.