ArchiveStoreItem.java (freenet.client)

//s243a pearltree node: http://www.pearltrees.com/s243a/archivestoreitem-freenet/id12827747
/* This code is part of Freenet. It is distributed under the GNU General
 * Public License, version 2 (or at your option any later version). See
 * http://www.gnu.org/ for further details of the GPL. */
package freenet.client;

import com.db4o.ObjectContainer;

import freenet.support.DoublyLinkedListImpl;
import freenet.support.Logger;
import freenet.support.api.Bucket;

/**
 * Base class for items stored in the archive cache.
 */
abstract class ArchiveStoreItem extends DoublyLinkedListImpl.Item<ArchiveStoreItem> {
    final ArchiveKey key;
    final ArchiveStoreContext context;

    /** Basic constructor. */
    ArchiveStoreItem(ArchiveKey key, ArchiveStoreContext context) {
        this.key = key;
        this.context = context;
        context.addItem(this);
    }

    /** Delete any stored data on disk etc.
     * Override in subtypes for specific cleanup.
     * Will be called with locks held, so should only do low level operations
     * such as deletes.. */
    void innerClose() { } // override in subtypes for cleanup

    /**
     * Shortcut to start the removal/cleanup process.
     */
    final void close() {
        context.removeItem(this);
    }

    /**
     * Return cached data as a Bucket, or throw an ArchiveFailureException.
     */
    abstract Bucket getDataOrThrow() throws ArchiveFailureException;

    /**
     * Return the amount of cache space used by the item. May be called inside
     * locks so should not take any nontrivial locks or take long.
     */
    abstract long spaceUsed();

    /**
     * Get the data as a Bucket, and guarantee that it won't be freed until the
     * returned object is either finalized or freed.
     */
    abstract Bucket getReaderBucket() throws ArchiveFailureException;

    public boolean objectCanNew(ObjectContainer container) {
        Logger.error(this, "Trying to store an ArchiveStoreItem!", new Exception("error"));
        return false;
    }

    public boolean objectCanUpdate(ObjectContainer container) {
        Logger.error(this, "Trying to store an ArchiveStoreItem!", new Exception("error"));
        return false;
    }

    public boolean objectCanActivate(ObjectContainer container) {
        Logger.error(this, "Trying to store an ArchiveStoreItem!", new Exception("error"));
        return false;
    }

    public boolean objectCanDeactivate(ObjectContainer container) {
        Logger.error(this, "Trying to store an ArchiveStoreItem!", new Exception("error"));
        return false;
    }

}