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* as indicated by the @author tags. See the copyright.txt file in the
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*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
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*
* This software is distributed in the hope that it will be useful,
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
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package org.jboss.cache.interceptors;
import org.jboss.cache.DataContainer;
import org.jboss.cache.Fqn;
import org.jboss.cache.InternalNode;
import org.jboss.cache.InvocationContext;
import org.jboss.cache.NodeSPI;
import org.jboss.cache.commands.VisitableCommand;
import org.jboss.cache.commands.read.ExistsCommand;
import org.jboss.cache.commands.read.GetChildrenNamesCommand;
import org.jboss.cache.commands.read.GetDataMapCommand;
import org.jboss.cache.commands.read.GetKeyValueCommand;
import org.jboss.cache.commands.read.GetKeysCommand;
import org.jboss.cache.commands.read.GetNodeCommand;
import org.jboss.cache.commands.read.GravitateDataCommand;
import org.jboss.cache.commands.tx.CommitCommand;
import org.jboss.cache.commands.tx.PrepareCommand;
import org.jboss.cache.commands.tx.RollbackCommand;
import org.jboss.cache.commands.write.ClearDataCommand;
import org.jboss.cache.commands.write.EvictCommand;
import org.jboss.cache.commands.write.InvalidateCommand;
import org.jboss.cache.commands.write.MoveCommand;
import org.jboss.cache.commands.write.PutDataMapCommand;
import org.jboss.cache.commands.write.PutForExternalReadCommand;
import org.jboss.cache.commands.write.PutKeyValueCommand;
import org.jboss.cache.commands.write.RemoveKeyCommand;
import org.jboss.cache.commands.write.RemoveNodeCommand;
import org.jboss.cache.factories.annotations.Inject;
import org.jboss.cache.interceptors.base.PrePostProcessingCommandInterceptor;
import org.jboss.cache.lock.LockManager;
import org.jboss.cache.mvcc.MVCCNodeHelper;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
import java.util.ListIterator;
import java.util.Map;
/**
* Interceptor to implement <a href="http://wiki.jboss.org/wiki/JBossCacheMVCC">MVCC</a> functionality.
*
* @author Manik Surtani (<a href="mailto:manik AT jboss DOT org">manik AT jboss DOT org</a>)
* @see <a href="http://wiki.jboss.org/wiki/JBossCacheMVCC">MVCC designs</a>
* @since 3.0
*/
public class MVCCLockingInterceptor extends PrePostProcessingCommandInterceptor
{
LockManager lockManager;
DataContainer dataContainer;
MVCCNodeHelper helper;
@Inject
public void setDependencies(LockManager lockManager, DataContainer dataContainer, MVCCNodeHelper helper)
{
this.lockManager = lockManager;
this.dataContainer = dataContainer;
this.helper = helper;
}
@Override
protected boolean doBeforeCall(InvocationContext ctx, VisitableCommand command)
{
if (ctx.getOptionOverrides().isSuppressLocking() && log.isWarnEnabled()) log.warn("Lock suppression not supported with MVCC!");
return true;
}
@Override
public Object handlePutDataMapCommand(InvocationContext ctx, PutDataMapCommand command) throws Throwable
{
helper.wrapNodeForWriting(ctx, command.getFqn(), true, true, false, false, false); // get the node and stick it in the context.
return invokeNextInterceptor(ctx, command);
}
@Override
public Object handlePutKeyValueCommand(InvocationContext ctx, PutKeyValueCommand command) throws Throwable
{
helper.wrapNodeForWriting(ctx, command.getFqn(), true, true, false, false, false); // get the node and stick it in the context.
return invokeNextInterceptor(ctx, command);
}
@Override
public Object handlePutForExternalReadCommand(InvocationContext ctx, PutForExternalReadCommand command) throws Throwable
{
helper.wrapNodeForWriting(ctx, command.getFqn(), true, true, false, false, false); // get the node and stick it in the context.
return invokeNextInterceptor(ctx, command);
}
@Override
public Object handleRemoveNodeCommand(InvocationContext ctx, RemoveNodeCommand command) throws Throwable
{
helper.wrapNodesRecursivelyForRemoval(ctx, command.getFqn());
return invokeNextInterceptor(ctx, command);
}
@Override
public Object handleClearDataCommand(InvocationContext ctx, ClearDataCommand command) throws Throwable
{
helper.wrapNodeForWriting(ctx, command.getFqn(), true, false, false, false, false);
return invokeNextInterceptor(ctx, command);
}
@Override
public Object handleEvictFqnCommand(InvocationContext ctx, EvictCommand command) throws Throwable
{
// set lock acquisition timeout to 0 - we need to fail fast.
ctx.getOptionOverrides().setLockAcquisitionTimeout(0);
if (command.isRecursive())
{
handleRecursiveEvict(ctx, command);
}
else
{
handleNonrecursiveEvict(ctx, command);
}
return invokeNextInterceptor(ctx, command);
}
@SuppressWarnings("unchecked")
private void handleRecursiveEvict(InvocationContext ctx, EvictCommand command) throws InterruptedException
{
List<Fqn> fqnsToEvict;
if (command.getFqn().isRoot())
{
// if this is the root node, do not attempt to lock this for writing but instead just get all direct children of root.
Map<Object, InternalNode> children = dataContainer.peekInternalNode(Fqn.ROOT, false).getChildrenMap();
if (!children.isEmpty())
{
fqnsToEvict = new LinkedList<Fqn>();
// lock recursively.
for (InternalNode child : children.values())
fqnsToEvict.addAll(helper.wrapNodesRecursivelyForRemoval(ctx, child.getFqn()));
}
else
{
fqnsToEvict = Collections.emptyList();
}
}
else
{
// lock current node recursively.
fqnsToEvict = helper.wrapNodesRecursivelyForRemoval(ctx, command.getFqn());
}
// set these in the evict command so that the command is aware of what needs to be evicted.
command.setNodesToEvict(fqnsToEvict);
}
@SuppressWarnings("unchecked")
private void handleNonrecursiveEvict(InvocationContext ctx, EvictCommand command) throws InterruptedException
{
if (command.getFqn().isRoot())
{
// if this is the root node, do not attempt to lock this for writing but instead just get all direct children of root.
Map<Object, InternalNode> children = dataContainer.peekInternalNode(Fqn.ROOT, false).getChildrenMap();
if (!children.isEmpty())
{
for (InternalNode child : children.values())
helper.wrapNodeForWriting(ctx, child.getFqn(), true, false, false, true, true);
}
}
else
{
// just wrap the node for writing. Do not create if absent.
helper.wrapNodeForWriting(ctx, command.getFqn(), true, false, false, true, true);
}
}
@Override
public Object handleInvalidateCommand(InvocationContext ctx, InvalidateCommand command) throws Throwable
{
// this should be handled the same as a recursive evict command.
ctx.getOptionOverrides().setLockAcquisitionTimeout(0);
if (!command.getFqn().isRoot()) helper.wrapNodesRecursivelyForRemoval(ctx, command.getFqn());
return invokeNextInterceptor(ctx, command);
}
@Override
public Object handleRemoveKeyCommand(InvocationContext ctx, RemoveKeyCommand command) throws Throwable
{
helper.wrapNodeForWriting(ctx, command.getFqn(), true, false, false, false, false);
return invokeNextInterceptor(ctx, command);
}
@Override
public Object handleGetDataMapCommand(InvocationContext ctx, GetDataMapCommand command) throws Throwable
{
helper.wrapNodeForReading(ctx, command.getFqn(), true);
return invokeNextInterceptor(ctx, command);
}
@Override
public Object handleExistsNodeCommand(InvocationContext ctx, ExistsCommand command) throws Throwable
{
helper.wrapNodeForReading(ctx, command.getFqn(), true);
return invokeNextInterceptor(ctx, command);
}
@Override
public Object handleGetKeyValueCommand(InvocationContext ctx, GetKeyValueCommand command) throws Throwable
{
helper.wrapNodeForReading(ctx, command.getFqn(), true);
return invokeNextInterceptor(ctx, command);
}
@Override
public Object handleGetNodeCommand(InvocationContext ctx, GetNodeCommand command) throws Throwable
{
helper.wrapNodeForReading(ctx, command.getFqn(), true);
return invokeNextInterceptor(ctx, command);
}
@Override
public Object handleGetKeysCommand(InvocationContext ctx, GetKeysCommand command) throws Throwable
{
helper.wrapNodeForReading(ctx, command.getFqn(), true);
return invokeNextInterceptor(ctx, command);
}
@Override
public Object handleGetChildrenNamesCommand(InvocationContext ctx, GetChildrenNamesCommand command) throws Throwable
{
helper.wrapNodeForReading(ctx, command.getFqn(), true);
return invokeNextInterceptor(ctx, command);
}
@Override
public Object handleMoveCommand(InvocationContext ctx, MoveCommand command) throws Throwable
{
// Nodes we need to get WLs for:
// 1) node we are moving FROM, and its parent and ALL children. Same as removeNode.
List<Fqn> nodeAndChildren = helper.wrapNodesRecursivelyForRemoval(ctx, command.getFqn());
Fqn newParent = command.getTo();
Fqn oldParent = command.getFqn().getParent();
// 2) The new parent.
helper.wrapNodeForWriting(ctx, newParent, true, true, false, false, false);
if (!oldParent.equals(newParent))
{
// the nodeAndChildren list contains all child nodes, including the node itself.
// 3) now obtain locks on the new places these new nodes will occupy.
for (Fqn f : nodeAndChildren)
{
Fqn newChildFqn = f.replaceAncestor(oldParent, newParent);
helper.wrapNodeForWriting(ctx, newChildFqn, true, true, true, false, false);
}
}
// now pass up the chain.
return invokeNextInterceptor(ctx, command);
}
@Override
public Object handleGravitateDataCommand(InvocationContext ctx, GravitateDataCommand command) throws Throwable
{
helper.wrapNodeForReading(ctx, command.getFqn(), true);
return invokeNextInterceptor(ctx, command);
}
@Override
public Object handleRollbackCommand(InvocationContext ctx, RollbackCommand command) throws Throwable
{
Object retval = null;
try
{
retval = invokeNextInterceptor(ctx, command);
}
finally
{
transactionalCleanup(false, ctx);
}
return retval;
}
@Override
public Object handleCommitCommand(InvocationContext ctx, CommitCommand command) throws Throwable
{
Object retval = null;
try
{
retval = invokeNextInterceptor(ctx, command);
}
finally
{
transactionalCleanup(true, ctx);
}
return retval;
}
@Override
public Object handlePrepareCommand(InvocationContext ctx, PrepareCommand command) throws Throwable
{
Object retval = null;
try
{
retval = invokeNextInterceptor(ctx, command);
}
finally
{
if (command.isOnePhaseCommit()) transactionalCleanup(true, ctx);
}
return retval;
}
@SuppressWarnings("unchecked")
protected void doAfterCall(InvocationContext ctx, VisitableCommand command)
{
// for non-transactional stuff.
if (ctx.getTransactionContext() == null)
{
List<Fqn> locks;
if (!(locks = ctx.getLocks()).isEmpty())
{
cleanupLocks(locks, ctx, Thread.currentThread(), true);
}
else
{
if (trace) log.trace("Nothing to do since there are no modifications in scope.");
}
}
else
{
if (trace) log.trace("Nothing to do since there is a transaction in scope.");
}
}
private void cleanupLocks(List<Fqn> locks, InvocationContext ctx, Object owner, boolean commit)
{
// clean up.
// unlocking needs to be done in reverse order.
ListIterator<Fqn> it = locks.listIterator(locks.size());
if (commit)
{
while (it.hasPrevious())
{
Fqn f = it.previous();
NodeSPI rcn = ctx.lookUpNode(f);
// could be null with read-committed
if (rcn != null) rcn.commitUpdate(ctx, dataContainer);
// and then unlock
if (trace) log.trace("Releasing lock on [" + f + "] for owner " + owner);
lockManager.unlock(f, owner);
}
}
else
{
while (it.hasPrevious())
{
Fqn f = it.previous();
NodeSPI rcn = ctx.lookUpNode(f);
// could be null with read-committed
if (rcn != null) rcn.rollbackUpdate();
// and then unlock
if (trace) log.trace("Releasing lock on [" + f + "] for owner " + owner);
lockManager.unlock(f, owner);
}
}
ctx.clearLocks();
}
@SuppressWarnings("unchecked")
private void transactionalCleanup(boolean commit, InvocationContext ctx)
{
if (ctx.getTransactionContext() != null)
{
List<Fqn> locks = ctx.getTransactionContext().getLocks();
if (!locks.isEmpty()) cleanupLocks(locks, ctx, ctx.getGlobalTransaction(), commit);
}
else
{
throw new IllegalStateException("Attempting to do a commit or rollback but there is no transactional context in scope. " + ctx);
}
}
}