DeferredDeletablesManager.java
/*
** Module : DeferredDeletablesManager.java
** Abstract : Defines a manager for deletables which postpones them to a specific block.
**
** Copyright (c) 2020-2023, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------------Description----------------------------------------
** 001 AIL 20200518 Created initial version.
** AIL 20200616 Moved buffer logic to the procedure manager. Remade the getHandlingBlock().
** AIL 20200617 Moved the StaleProcedureHelper as separate class.
** Javadoc update.
** 002 CA 20220120 Improved performance for finalizables, keep them already sorted by their weight.
** CA 20221006 Check if 'block.finalizables' exists before iterating it. Refs #6824
** 003 CA 20231216 Avoid iterators when processing BlockDefinition.finalizables.
*/
/*
** This program is free software: you can redistribute it and/or modify
** it under the terms of the GNU Affero General Public License as
** published by the Free Software Foundation, either version 3 of the
** License, or (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU Affero General Public License for more details.
**
** You may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
**
** Additional terms under GNU Affero GPL version 3 section 7:
**
** Under Section 7 of the GNU Affero GPL version 3, the following additional
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** Affero GPL version 3 and may not be removed by you.
**
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*/
package com.goldencode.p2j.util;
import java.util.*;
/**
* Provides a mean of postponing deletion of deletable resources at a specific block level. This is useful
* where there are postpone deletes which can't be determined at the target place of deletion.
*/
public class DeferredDeletablesManager
implements Finalizable
{
/** The core collection of resources which are to be deleted when the manager is finished */
private final Set<DeferredDeletable> deletables = new HashSet<>();
/**
* Registers a resource at a specific block depth. This also handles the scenario in which there
* is already such manager registered at that block.
*
* @param blockDepth
* The index of the outermost block at which a manager should be registered; blockDepth 0
* means the global scope.
* @param resource
* The resource which is to be registered.
*
* @return <code>false</code> if the registration was skipped as this resource was already registered,
* <code>true</code> otherwise.
*/
public static boolean registerAt(int blockDepth, DeferredDeletable resource)
{
BlockDefinition block = TransactionManager.getBlockAtDepth(blockDepth);
Set<Finalizable>[] fini = block.finalizables;
if (fini != null)
{
for (int i = 0; i < fini.length; i++)
{
Set<Finalizable> l = fini[i];
if (l == null)
{
continue;
}
for (Finalizable finalizable : l)
{
if (finalizable instanceof DeferredDeletablesManager)
{
return ((DeferredDeletablesManager) finalizable).register(resource);
}
}
}
}
DeferredDeletablesManager ddm = new DeferredDeletablesManager();
ddm.register(resource);
TransactionManager.registerFinalizableAt(blockDepth, ddm);
return true;
}
/**
* Registers a specific deletable to this manager. While the collection is a set, the
* deletable won't be deleted twice.
*
* @param deletable
* A resource meant to be registered for deletion.
*
* @return <code>true</code> if the register was successful or <code>false</code> if the
* deletable was already registered in this manager.
*/
public boolean register(DeferredDeletable deletable)
{
return deletables.add(deletable);
}
/**
* Does the effective delete of the registered resources when this manager is finished.
*/
@Override
public void finished()
{
for (DeferredDeletable deletable : deletables)
{
deletable.deferredDelete();
}
}
/**
* The method is a no-op due to the fact that the delete defer is made only when the
* the manager is notified through the {@code finished} method.
*/
@Override
public void deleted()
{
// no-op
}
/**
* The method is a no-op due to the fact that the delete defer is made only when the
* the manager is notified through the {@code finished} method.
*/
@Override
public void iterate()
{
// no-op
}
/**
* The method is a no-op due to the fact that the delete defer is made only when the
* the manager is notified through the {@code finished} method.
*/
@Override
public void retry()
{
// no-op
}
}