jena-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From a...@apache.org
Subject [075/100] [abbrv] jena git commit: JENA-1397: Rename java packages
Date Thu, 28 Sep 2017 16:06:27 GMT
http://git-wip-us.apache.org/repos/asf/jena/blob/3d456654/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionCoordinator.java
----------------------------------------------------------------------
diff --git a/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionCoordinator.java b/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionCoordinator.java
deleted file mode 100644
index 8a866a9..0000000
--- a/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionCoordinator.java
+++ /dev/null
@@ -1,805 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.seaborne.dboe.transaction.txn;
-
-import static org.apache.jena.query.ReadWrite.WRITE ;
-import static org.seaborne.dboe.transaction.txn.journal.JournalEntryType.UNDO ;
-
-import java.nio.ByteBuffer ;
-import java.util.ArrayList ;
-import java.util.Iterator ;
-import java.util.List ;
-import java.util.Objects ;
-import java.util.concurrent.ConcurrentHashMap ;
-import java.util.concurrent.Semaphore ;
-import java.util.concurrent.atomic.AtomicLong ;
-import java.util.concurrent.locks.ReadWriteLock ;
-import java.util.concurrent.locks.ReentrantReadWriteLock ;
-
-import org.apache.jena.atlas.logging.Log ;
-import org.apache.jena.query.ReadWrite ;
-import org.seaborne.dboe.base.file.Location ;
-import org.seaborne.dboe.sys.Sys ;
-import org.seaborne.dboe.transaction.txn.journal.Journal ;
-import org.seaborne.dboe.transaction.txn.journal.JournalEntry ;
-import org.slf4j.Logger ;
-
-/**
- * One {@code TransactionCoordinator} per group of {@link TransactionalComponent}s.
- * {@link TransactionalComponent}s can not be shared across TransactionCoordinators.
- * <p>
- * This is a general engine although tested and most used for multiple-reader
- * and single-writer (MR+SW). {@link TransactionalComponentLifecycle} provides the
- * per-threadstyle.
- * <p>
- * Contrast to MRSW: multiple-reader or single-writer.
- * <h3>Block writers</h3>
- * Block until no writers are active.
- * When this returns, this guarantees that the database is not changing
- * and the journal is flushed to disk.
- * <p>
- * See {@link #blockWriters()}, {@link #enableWriters()}, {@link #execAsWriter(Runnable)}
- * <h3>Excluisve mode</h3>
- * Exclusive mode is when the current thread is the only active code : no readers, no writers.
- * <p>
- * See {@link #startExclusiveMode()}/{@link #tryExclusiveMode()} {@link #finishExclusiveMode()}, {@link #execExclusive(Runnable)}
- *
- * @see Transaction
- * @see TransactionalComponent
- * @see TransactionalSystem
- */
-final
-public class TransactionCoordinator {
-    private static Logger log = Sys.syslog ;
-    
-    private final Journal journal ;
-    private boolean coordinatorStarted = false ;
-
-    private final ComponentGroup components = new ComponentGroup() ;
-    // Components 
-    private ComponentGroup txnComponents = null ;
-    private List<ShutdownHook> shutdownHooks ;
-    private TxnIdGenerator txnIdGenerator = TxnIdFactory.txnIdGenSimple ;
-    
-    private QuorumGenerator quorumGenerator = null ;
-    //private QuorumGenerator quorumGenerator = (m) -> components ;
-
-    // Semaphore to implement "Single Active Writer" - independent of readers
-    // This is not reentrant.
-    private Semaphore writersWaiting = new Semaphore(1, true) ;
-    
-    // All transaction need a "read" lock through out their lifetime. 
-    // Do not confuse with read/write transactions.  We need a 
-    // "one exclusive, or many other" lock which happens to be called ReadWriteLock
-    // See also {@code lock} which protects the datastructures during transaction management.  
-    private ReadWriteLock exclusivitylock = new ReentrantReadWriteLock() ;
-
-    // Coordinator wide lock object.
-    private Object coordinatorLock = new Object() ;
-
-    @FunctionalInterface
-    public interface ShutdownHook { void shutdown() ; }
-
-    /** Create a TransactionCoordinator, initially with no associated {@link TransactionalComponent}s */ 
-    public TransactionCoordinator(Location location) {
-        this(Journal.create(location)) ;
-    }
-    
-    /** Create a TransactionCoordinator, initially with no associated {@link TransactionalComponent}s */ 
-    public TransactionCoordinator(Journal journal) {
-        this(journal, null , new ArrayList<>()) ;
-    }
-
-    /** Create a TransactionCoordinator, initially with {@link TransactionalComponent} in the ComponentGroup */
-    public TransactionCoordinator(Journal journal, List<TransactionalComponent> components) {
-        this(journal, components , new ArrayList<>()) ;
-    }
-
-    //    /** Create a TransactionCoordinator, initially with no associated {@link TransactionalComponent}s */ 
-//    public TransactionCoordinator(Location journalLocation) {
-//        this(Journal.create(journalLocation), new ArrayList<>() , new ArrayList<>()) ;
-//    }
-
-    private TransactionCoordinator(Journal journal, List<TransactionalComponent> txnComp, List<ShutdownHook> shutdownHooks) { 
-        this.journal = journal ;
-        this.shutdownHooks = new ArrayList<>(shutdownHooks) ;
-        if ( txnComp != null ) {
-            //txnComp.forEach(x-> System.out.println(x.getComponentId().label()+" :: "+Bytes.asHex(x.getComponentId().bytes()) ) ) ;
-            txnComp.forEach(components::add);
-        }
-    }
-    
-    /** Add a {@link TransactionalComponent}.
-     * Safe to call at any time but it is good practice is to add all the
-     * compoents before any transactions start.
-     * Internally, the coordinator ensures the add will safely happen but it
-     * does not add the component to existing transactions.
-     * This must be setup before recovery is attempted. 
-     */
-    public TransactionCoordinator add(TransactionalComponent elt) {
-        checkSetup() ;
-        synchronized(coordinatorLock) {
-            components.add(elt) ;
-        }
-        return this ;
-    }
-
-    /** 
-     * Remove a {@link TransactionalComponent}.
-     * @see #add 
-     */
-    public TransactionCoordinator remove(TransactionalComponent elt) {
-        checkSetup() ;
-        synchronized(coordinatorLock) {
-            components.remove(elt.getComponentId()) ;
-        }
-        return this ;
-    }
-
-    /**
-     * Add a shutdown hook. Shutdown is not guaranteed to be called
-     * and hence hooks may not get called.
-     */
-    public void add(TransactionCoordinator.ShutdownHook hook) {
-        checkSetup() ;
-        synchronized(coordinatorLock) {
-            shutdownHooks.add(hook) ;
-        }
-    }
-
-    /** Remove a shutdown hook */
-    public void remove(TransactionCoordinator.ShutdownHook hook) {
-        checkSetup() ;
-        synchronized(coordinatorLock) {
-            shutdownHooks.remove(hook) ;
-        }
-    }
-    
-    public void setQuorumGenerator(QuorumGenerator qGen) {
-        checkSetup() ;
-        this.quorumGenerator = qGen ;
-    }
-
-    public void start() {
-        checkSetup() ;
-        recovery() ;
-        coordinatorStarted = true ;
-    }
-
-    private /*public*/ void recovery() {
-        
-        Iterator<JournalEntry> iter = journal.entries() ;
-        if ( ! iter.hasNext() ) {
-            components.forEachComponent(c -> c.cleanStart()) ;
-            return ;
-        }
-        
-        log.info("Journal recovery start") ;
-        components.forEachComponent(c -> c.startRecovery()) ;
-        
-        // Group to commit
-        
-        List<JournalEntry> entries = new ArrayList<>() ;
-        
-        iter.forEachRemaining( entry -> {
-            switch(entry.getType()) {
-                case ABORT :
-                    entries.clear() ;
-                    break ;
-                case COMMIT :
-                    recover(entries) ;
-                    entries.clear() ;
-                    break ;
-                case REDO : case UNDO :
-                    entries.add(entry) ;
-                    break ;
-            }
-        }) ;
-    
-        components.forEachComponent(c -> c.finishRecovery()) ;
-        journal.reset() ;
-        log.info("Journal recovery end") ;
-    }
-
-    private void recover(List<JournalEntry> entries) {
-        entries.forEach(e -> {
-            if ( e.getType() == UNDO ) {
-                Log.warn(TransactionCoordinator.this, "UNDO entry : not handled") ;  
-                return ;
-            }
-            ComponentId cid = e.getComponentId() ;
-            ByteBuffer bb = e.getByteBuffer() ;
-            // find component.
-            TransactionalComponent c = components.findComponent(cid) ;
-            if ( c == null ) {
-                Log.warn(TransactionCoordinator.this, "No component for "+cid) ;
-                return ;
-            }
-            c.recover(bb); 
-        }) ;
-    }
-
-    public void setTxnIdGenerator(TxnIdGenerator generator) {
-        this.txnIdGenerator = generator ;
-    }
-    
-    public Journal getJournal() {
-        return journal ;
-    }
-    
-    public TransactionCoordinatorState detach(Transaction txn) {
-        txn.detach();
-        TransactionCoordinatorState coordinatorState = new TransactionCoordinatorState(txn) ;
-        components.forEach((id, c) -> {
-            SysTransState s = c.detach() ;
-            coordinatorState.componentStates.put(id, s) ;
-        } ) ;
-        // The txn still counts as "active" for tracking purposes below.
-        return coordinatorState ;
-    }
-
-    public void attach(TransactionCoordinatorState coordinatorState) {
-        Transaction txn = coordinatorState.transaction ;
-        txn.attach() ;
-        coordinatorState.componentStates.forEach((id, obj) -> {
-            components.findComponent(id).attach(obj);
-        });
-    }
-
-    public void shutdown() {
-        if ( coordinatorLock == null )
-            return ;
-        components.forEach((id, c) -> c.shutdown()) ;
-        shutdownHooks.forEach((h)-> h.shutdown()) ;
-        coordinatorLock = null ;
-        journal.close(); 
-    }
-
-    // Are we in the initialization phase?
-    private void checkSetup() {
-        if ( coordinatorStarted )
-            throw new TransactionException("TransactionCoordinator has already been started") ;
-    }
-
-    // Are we up and ruuning?
-    private void checkActive() {
-        if ( ! coordinatorStarted )
-            throw new TransactionException("TransactionCoordinator has not been started") ;
-        checkNotShutdown();
-    }
-
-    // Check not wrapped up
-    private void checkNotShutdown() {
-        if ( coordinatorLock == null )
-            throw new TransactionException("TransactionCoordinator has been shutdown") ;
-    }
-
-    private void releaseWriterLock() {
-        int x = writersWaiting.availablePermits() ;
-        if ( x != 0 )
-            throw new TransactionException("TransactionCoordinator: Probably mismatch of enable/disableWriter calls") ;
-        writersWaiting.release() ;
-    }
-    
-    /** Acquire the writer lock - return true if succeeded */
-    private boolean acquireWriterLock(boolean canBlock) {
-        if ( ! canBlock )
-            return writersWaiting.tryAcquire() ;
-        try { 
-            writersWaiting.acquire() ; 
-            return true;
-        } catch (InterruptedException e) { throw new TransactionException(e) ; }
-    }
-    
-    /** Enter exclusive mode; block if necessary.
-     * There are no active transactions on return; new transactions will be held up in 'begin'.
-     * Return to normal (release waiting transactions, allow new transactions)
-     * with {@link #finishExclusiveMode}.
-     * <p>
-     * Do not call inside an existing transaction.
-     */
-    public void startExclusiveMode() {
-        startExclusiveMode(true);
-    }
-    
-    /** Try to enter exclusive mode. 
-     *  If return is true, then there are no active transactions on return and new transactions will be held up in 'begin'.
-     *  If false, there were in-progress transactions.
-     *  Return to normal (release waiting transactions, allow new transactions)
-     *  with {@link #finishExclusiveMode}.   
-     * <p>
-     * Do not call inside an existing transaction.
-     */
-    public boolean tryExclusiveMode() {
-        return tryExclusiveMode(false);
-    }
-    
-    /** Try to enter exclusive mode.  
-     *  If return is true, then there are no active transactions on return and new transactions will be held up in 'begin'.
-     *  If false, there were in-progress transactions.
-     *  Return to normal (release waiting transactions, allow new transactions)
-     *  with {@link #finishExclusiveMode}.   
-     * <p>
-     * Do not call inside an existing transaction.
-     * @param canBlock Allow the operation block and wait for the exclusive mode lock.
-     */
-    public boolean tryExclusiveMode(boolean canBlock) {
-        return startExclusiveMode(canBlock);
-    }
-
-    private boolean startExclusiveMode(boolean canBlock) {
-        if ( canBlock ) {
-            exclusivitylock.writeLock().lock() ;
-            return true ;
-        }
-        return exclusivitylock.writeLock().tryLock() ;
-    }
-
-    /** Return to normal (release waiting transactions, allow new transactions).
-     * Must be paired with an earlier {@link #startExclusiveMode}. 
-     */
-    public void finishExclusiveMode() {
-        exclusivitylock.writeLock().unlock() ;
-    }
-
-    /** Execute an action in exclusive mode.  This method can block.
-     * Equivalent to:
-     * <pre>
-     *  startExclusiveMode() ;
-     *  try { action.run(); }
-     *  finally { finishExclusiveMode(); }
-     * </pre>
-     * 
-     * @param action
-     */
-    public void execExclusive(Runnable action) {
-        startExclusiveMode() ;
-        try { action.run(); }
-        finally { finishExclusiveMode(); }
-    }
-    
-    /** Block until no writers are active.
-     *  When this returns, this guarantees that the database is not changing
-     *  and the journal is flushed to disk.
-     * <p> 
-     * The application must call {@link #enableWriters} later.
-     * <p> 
-     * This operation must not be nested (it will block).
-     * 
-     * @see #tryBlockWriters()
-     * @see #enableWriters()
-     * 
-     */
-    public void blockWriters() {
-        acquireWriterLock(true) ;
-    }
-
-    /** Try to block all writers, or return if can't at the moment.
-     * <p>
-     * Unlike a write transction, there is no associated transaction. 
-     * <p>
-     * If it returns true, the application must call {@link #enableWriters} later.
-     *  
-     * @see #blockWriters()
-     * @see #enableWriters()
-
-     * @return true if the operation succeeded and writers are blocked 
-     */
-    public boolean tryBlockWriters() {
-        return tryBlockWriters(false) ;
-    }
-
-    /**
-     * Block until no writers are active, optionally blocking or returning if can't at the moment.
-     * <p>
-     * Unlike a write transction, there is no associated transaction. 
-     * <p>
-     * If it returns true, the application must call {@link #enableWriters} later.
-     * @param canBlock
-     * @return true if the operation succeeded and writers are blocked
-     */
-    public boolean tryBlockWriters(boolean canBlock) {
-        return acquireWriterLock(canBlock) ;
-    }
-    /** Allow writers.  
-     * This must be used in conjunction with {@link #blockWriters()} or {@link #tryBlockWriters()}
-     * 
-     * @see #blockWriters()
-     * @see #tryBlockWriters()
-     */ 
-    public void enableWriters() {
-        releaseWriterLock();
-    }
-    
-    /** Execute an action in as if a Write but no write transaction started.
-     * This method can block.
-     * <p>
-     * Equivalent to:
-     * <pre>
-     *  blockWriters() ;
-     *  try { action.run(); }
-     *  finally { enableWriters(); }
-     * </pre>
-     * 
-     * @param action
-     */
-    public void execAsWriter(Runnable action) {
-        blockWriters() ;
-        try { action.run(); }
-        finally { enableWriters(); }
-    }
-    
-    /** Start a transaction. This may block. */
-    public Transaction begin(ReadWrite readWrite) {
-        return begin(readWrite, true) ;
-    }
-    
-    /** 
-     * Start a transaction.  Returns null if this operation would block.
-     * Readers can start at any time.
-     * A single writer policy is currently imposed so a "begin(WRITE)"
-     * may block.  
-     */
-    public Transaction begin(ReadWrite readWrite, boolean canBlock) {
-        Objects.nonNull(readWrite) ;
-        checkActive() ;
-        
-        // XXX Flag to bounce writers fpor long term "block writers"
-        if ( false /* bounceWritersAtTheMoment */) {
-            if ( readWrite == WRITE ) {
-                throw new TransactionException("Writers currently being rejected");
-            }
-        }
-        
-        if ( canBlock )
-            exclusivitylock.readLock().lock() ;
-        else {
-            if ( ! exclusivitylock.readLock().tryLock() )
-                return null ;
-        }
-        
-        // Readers never block.
-        if ( readWrite == WRITE ) {
-            // Writers take a WRITE permit from the semaphore to ensure there
-            // is at most one active writer, else the attempt to start the
-            // transaction blocks.
-            // Released by in notifyCommitFinish/notifyAbortFinish
-            boolean b = acquireWriterLock(canBlock) ;
-            if ( !b ) {
-                exclusivitylock.readLock().unlock() ;
-                return null ;
-            }
-        }
-        Transaction transaction = begin$(readWrite) ;
-        startActiveTransaction(transaction) ;
-        transaction.begin();
-        return transaction;
-    }
-    
-    // The version is the serialization point for a transaction.
-    // All transactions on the same view of the data get the same serialization point.
-    
-    // A read transaction can be promoted if writer does not start
-    // This TransactionCoordinator provides Serializable, Read-lock-free
-    // execution.  With no item locking, a read can only be promoted
-    // if no writer started since the reader started.
-
-    /* The version of the data - incremented when transaction commits.
-     * This is the version with repest to the last commited transaction.
-     * Aborts do not cause the data version to advance. 
-     * This counterr never goes backwards.
-     */ 
-    private final AtomicLong dataVersion = new AtomicLong(0) ;
-    
-    private Transaction begin$(ReadWrite readWrite) {
-        synchronized(coordinatorLock) {
-            // Thread safe part of 'begin'
-            // Allocate the transaction serialization point.
-            TxnId txnId = txnIdGenerator.generate() ;
-            List<SysTrans> sysTransList = new ArrayList<>() ;
-            Transaction transaction = new Transaction(this, txnId, readWrite, dataVersion.get(), sysTransList) ;
-            
-            ComponentGroup txnComponents = chooseComponents(this.components, readWrite) ;
-            
-            try {
-                txnComponents.forEachComponent(elt -> {
-                    SysTrans sysTrans = new SysTrans(elt, transaction, txnId) ;
-                    sysTransList.add(sysTrans) ; }) ;
-                // Calling each component must be inside the lock
-                // so that a transaction does not commit overlapping with setup.
-                // If it did, different components might end up starting from
-                // different start states of the overall system.
-                txnComponents.forEachComponent(elt -> elt.begin(transaction)) ;
-            } catch(Throwable ex) {
-                // Careful about incomplete.
-                //abort() ;
-                //complete() ;
-                throw ex ;
-            }
-            return transaction ;
-        }
-    }
-    
-    private ComponentGroup chooseComponents(ComponentGroup components, ReadWrite readWrite) {
-        if ( quorumGenerator == null )
-            return components ;
-        ComponentGroup cg = quorumGenerator.genQuorum(readWrite) ;
-        if ( cg == null )
-            return components ;
-        cg.forEach((id, c) -> {
-            TransactionalComponent tcx = components.findComponent(id) ;
-            if ( ! tcx.equals(c) )
-                log.warn("TransactionalComponent not in TransactionCoordinator's ComponentGroup") ; 
-        }) ;
-        if ( log.isDebugEnabled() )
-            log.debug("Custom ComponentGroup for transaction "+readWrite+": size="+cg.size()+" of "+components.size()) ;
-        return cg ;
-    }
-
-    /** Is promotion of transactions enabled? */ 
-    /*private*/public/*for development*/ static boolean promotion               = true ;
-    
-    /** Control of whether a transaction promotion can see any commits that
-     *  happened between this transaction starting and it promoting.
-     *  A form of "ReadCommitted".   
-     */
-    /*private*/public/*for development*/ static boolean readCommittedPromotion  = false ;
-    
-    /** Whether to wait for writers when trying to promote */
-    private static final boolean promotionWaitForWriters = true;
-
-    /** Attempt to promote a tranasaction from READ to WRITE.
-     * No-op for a transaction already a writer.
-     * Throws {@link TransactionException} if the promotion
-     * can not be done.
-     */
-    /*package*/ boolean promoteTxn(Transaction transaction) {
-        if ( ! promotion )
-            return false;
-
-        if ( transaction.getMode() == WRITE )
-            return true ;
-        
-        // Has there been an writer active since the transaction started?
-        // Do a test outside the lock - only dataVaersion can change and that increases.
-        // If "read commited transactions" not allowed, the data has changed in a way we
-        // do no twish to expose.
-        // If this test fails outside the lock it will fail inside.
-        // If it passes, we have to test again in case there is an active writer.
-        
-        if ( ! readCommittedPromotion ) {
-            long txnEpoch = transaction.getDataVersion() ;      // The transaction-start point.
-            long currentEpoch = dataVersion.get() ;             // The data serialization point.
-            
-            if ( txnEpoch < currentEpoch )
-                // The data has changed and "read committed" not allowed.
-                // We can reject now.
-                return false ;
-        }
-        
-        // Once we have acquireWriterLock, we are single writer.
-        // We may have to discard writer status because eocne we can make the defintite
-        // decision on promotion, we find we can't promote after all.
-        if ( readCommittedPromotion ) {
-            /*
-             * acquireWriterLock(true) ;
-             * synchronized(coordinatorLock) {
-             * begin$ ==>
-             *    reset transaction.
-             *    promote components
-             *    reset dataVersion
-             */
-            acquireWriterLock(true) ;
-            synchronized(coordinatorLock) {
-                try { 
-                    transaction.promoteComponents() ;
-                    // Because we want to see the new state of the data.s
-                    //transaction.resetDataVersion(dataVersion.get());
-                } catch (TransactionException ex) {
-                    try { transaction.abort(); } catch(RuntimeException ex2) {}
-                    releaseWriterLock();
-                    return false ;
-                }
-            }
-            return true;
-        }
-        
-        if ( ! waitForWriters() )
-            // Failed to become a writer.
-            return false;
-        // Now a proto-writer.
-        
-        synchronized(coordinatorLock) {
-            // Not read commited.
-            // Need to check the data version once we are the writer and all previous
-            // writers have commited or aborted.
-            // Has there been an writer active since the transaction started?
-            long txnEpoch = transaction.getDataVersion() ;    // The transaction-start point.
-            long currentEpoch = dataVersion.get() ;         // The data serialization point.
-
-            if ( txnEpoch != currentEpoch ) {
-                // Failed to promote.
-                releaseWriterLock();
-                return false ;
-            }
-            
-            // ... we have now got the writer lock ...
-            try { 
-                transaction.promoteComponents() ;
-                // No need to reset the data version because strict isolation. 
-            } catch (TransactionException ex) {
-                try { transaction.abort(); } catch(RuntimeException ex2) {}
-                releaseWriterLock();
-                return false ;
-            }
-        }
-        return true ;
-    }
-        
-    private boolean waitForWriters() {
-        if ( promotionWaitForWriters )
-            return acquireWriterLock(true) ;
-        else
-            return acquireWriterLock(false) ;
-    }
-
-    // Called once by Transaction after the action of commit()/abort() or end()
-    /** Signal that the transaction has finished. */  
-    /*package*/ void completed(Transaction transaction) {
-        finishActiveTransaction(transaction);
-        journal.reset() ;
-    }
-
-    /*package*/ void executePrepare(Transaction transaction) {
-        // Do here because it needs access to the journal.
-        notifyPrepareStart(transaction);
-        transaction.getComponents().forEach(sysTrans -> {
-            TransactionalComponent c = sysTrans.getComponent() ;
-            ByteBuffer data = c.commitPrepare(transaction) ;
-            if ( data != null ) {
-                PrepareState s = new PrepareState(c.getComponentId(), data) ;
-                journal.write(s) ;
-            }
-        }) ;
-        notifyPrepareFinish(transaction);
-    }
-
-    /*package*/ void executeCommit(Transaction transaction,  Runnable commit, Runnable finish) {
-        // This is the commit point. 
-        synchronized(coordinatorLock) {
-            // *** COMMIT POINT
-            journal.sync() ;
-            // *** COMMIT POINT
-            // Now run the Transactions commit actions. 
-            commit.run() ;
-            journal.truncate(0) ;
-            // and tell the Transaction it's finished. 
-            finish.run() ;
-            // Bump global serialization point if necessary.
-            if ( transaction.getMode() == WRITE )
-                advanceDataVersion() ;
-            notifyCommitFinish(transaction) ;
-        }
-    }
-    
-    // Inside the global transaction start/commit lock.
-    private void advanceDataVersion() {
-        dataVersion.incrementAndGet();
-    }
-    
-    /*package*/ void executeAbort(Transaction transaction, Runnable abort) {
-        notifyAbortStart(transaction) ;
-        abort.run();
-        notifyAbortFinish(transaction) ;
-    }
-    
-    // Active transactions: this is (the missing) ConcurrentHashSet
-    private final static Object dummy                   = new Object() ;    
-    private ConcurrentHashMap<Transaction, Object> activeTransactions = new ConcurrentHashMap<>() ;
-    private AtomicLong activeTransactionCount = new AtomicLong(0) ;
-    private AtomicLong activeReadersCount = new AtomicLong(0) ;
-    private AtomicLong activeWritersCount = new AtomicLong(0) ;
-    
-    private void startActiveTransaction(Transaction transaction) {
-        synchronized(coordinatorLock) {
-            // Use lock to ensure all the counters move together.
-            // Thread safe - we have not let the Transaction object out yet.
-            countBegin.incrementAndGet() ;
-            switch(transaction.getMode()) {
-                case READ:  countBeginRead.incrementAndGet() ;  activeReadersCount.incrementAndGet() ; break ;
-                case WRITE: countBeginWrite.incrementAndGet() ; activeWritersCount.incrementAndGet() ; break ;
-            }
-            activeTransactionCount.incrementAndGet() ;
-            activeTransactions.put(transaction, dummy) ;
-        }
-    }
-    
-    private void finishActiveTransaction(Transaction transaction) {
-        synchronized(coordinatorLock) {
-            // Idempotent.
-            Object x = activeTransactions.remove(transaction) ;
-            if ( x == null )
-                return ;
-            countFinished.incrementAndGet() ;
-            activeTransactionCount.decrementAndGet() ;
-            switch(transaction.getMode()) {
-                case READ:  activeReadersCount.decrementAndGet() ; break ;
-                case WRITE: activeWritersCount.decrementAndGet() ; break ;
-            }
-        }
-        exclusivitylock.readLock().unlock() ; 
-    }
-    
-    public long countActiveReaders()    { return activeReadersCount.get() ; } 
-    public long countActiveWriter()     { return activeWritersCount.get() ; } 
-    public long countActive()           { return activeTransactionCount.get(); }
-    
-    // notify*Start/Finish called round each transaction lifecycle step
-    // Called in cooperation between Transaction and TransactionCoordinator
-    // depending on who is actually do the work of each step.
-
-    /*package*/ void notifyPrepareStart(Transaction transaction) {}
-
-    /*package*/ void notifyPrepareFinish(Transaction transaction) {}
-
-    // Writers released here - can happen because of commit() or abort(). 
-
-    private void notifyCommitStart(Transaction transaction) {}
-    
-    private void notifyCommitFinish(Transaction transaction) {
-        if ( transaction.getMode() == WRITE )
-            releaseWriterLock();
-    }
-    
-    private void notifyAbortStart(Transaction transaction) { }
-    
-    private void notifyAbortFinish(Transaction transaction) {
-        if ( transaction.getMode() == WRITE )
-            releaseWriterLock();
-    }
-
-    /*package*/ void notifyEndStart(Transaction transaction) { }
-
-    /*package*/ void notifyEndFinish(Transaction transaction) {}
-
-    // Called by Transaction once at the end of first commit()/abort() or end()
-    
-    /*package*/ void notifyCompleteStart(Transaction transaction) { }
-
-    /*package*/ void notifyCompleteFinish(Transaction transaction) { }
-
-    // Coordinator state.
-    private final AtomicLong countBegin         = new AtomicLong(0) ;
-
-    private final AtomicLong countBeginRead     = new AtomicLong(0) ;
-
-    private final AtomicLong countBeginWrite    = new AtomicLong(0) ;
-
-    private final AtomicLong countFinished      = new AtomicLong(0) ;
-
-    // Access counters
-    public long countBegin()        { return countBegin.get() ; }
-
-    public long countBeginRead()    { return countBeginRead.get() ; }
-
-    public long countBeginWrite()   { return countBeginWrite.get() ; }
-
-    public long countFinished()     { return countFinished.get() ; }
-}
-

http://git-wip-us.apache.org/repos/asf/jena/blob/3d456654/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionCoordinatorState.java
----------------------------------------------------------------------
diff --git a/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionCoordinatorState.java b/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionCoordinatorState.java
deleted file mode 100644
index 7402cc1..0000000
--- a/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionCoordinatorState.java
+++ /dev/null
@@ -1,34 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.seaborne.dboe.transaction.txn;
-
-import java.util.HashMap ;
-import java.util.Map ;
-
-public class TransactionCoordinatorState {
-    /*package*/final Transaction transaction ;
-    /*package*/Map<ComponentId, SysTransState> componentStates = new HashMap<>();
-    /*package*/ TransactionCoordinatorState(Transaction transaction) {
-        this.transaction = transaction ;
-    }
-    
-    public Transaction getTransaction() {
-        return transaction ;
-    }
-}

http://git-wip-us.apache.org/repos/asf/jena/blob/3d456654/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionException.java
----------------------------------------------------------------------
diff --git a/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionException.java b/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionException.java
deleted file mode 100644
index f15a22b..0000000
--- a/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionException.java
+++ /dev/null
@@ -1,30 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.seaborne.dboe.transaction.txn;
-
-import org.apache.jena.sparql.JenaTransactionException ;
-
-public class TransactionException extends JenaTransactionException {
-    public TransactionException()                                  { super(); }
-    public TransactionException(String message)                    { super(message); }
-    public TransactionException(Throwable cause)                   { super(cause) ; }
-    public TransactionException(String message, Throwable cause)   { super(message, cause) ; }
-
-}
-

http://git-wip-us.apache.org/repos/asf/jena/blob/3d456654/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionInfo.java
----------------------------------------------------------------------
diff --git a/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionInfo.java b/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionInfo.java
deleted file mode 100644
index a0a9483..0000000
--- a/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionInfo.java
+++ /dev/null
@@ -1,76 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.seaborne.dboe.transaction.txn;
-
-import static org.seaborne.dboe.transaction.txn.TxnState.INACTIVE ;
-import org.apache.jena.query.ReadWrite ;
-
-/** 
- * A view that provides information about a transaction
- * @see Transaction
- */
-public interface TransactionInfo {
-
-    /** The transaction lifecycle state */
-    public TxnState getState() ;
-
-    /**
-     * Each transaction is allocated a serialization point by the transaction
-     * coordinator. Normally, this is related to this number and it increases
-     * over time as the data changes. Two readers can have the same
-     * serialization point - they are working with the same view of the data.
-     */
-    public long getDataVersion() ;
-
-    /** Has the transaction started? */ 
-    public boolean hasStarted() ;
-    
-    /** Has the transaction finished (has commit/abort/end been called)? */ 
-    public boolean hasFinished() ; 
-
-    /** Has the transaction gone through all lifecycle states? */ 
-    public boolean hasFinalised() ; 
-
-    /** Get the trasnaction id for this transaction. Unique within this OS process (JVM) at least . */
-    public TxnId getTxnId() ; 
-
-    /** What mode is this transaction?
-     *  This may change from {@code READ} to {@code WRITE} in a transactions lifetime.  
-     */
-    public ReadWrite getMode() ;
-    
-    /** Is this a view of a READ transaction?
-     * Convenience operation equivalent to {@code (getMode() == READ)}
-     */
-    public default boolean isReadTxn()  { return getMode() == ReadWrite.READ ; }
-    
-    /** Is this a view of a WRITE transaction?
-     * Convenience operation equivalent to {@code (getMode() == WRITE)}
-     */
-    public default boolean isWriteTxn()  { return getMode() == ReadWrite.WRITE ; }
-    
-    /** Is this a view of a transaction that is active?
-     * Equivalent to {@code getState() != INACTIVE} 
-     */
-    public default boolean isActiveTxn() { 
-        return getState() != INACTIVE ;
-    }
-
-}
-

http://git-wip-us.apache.org/repos/asf/jena/blob/3d456654/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalBase.java
----------------------------------------------------------------------
diff --git a/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalBase.java b/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalBase.java
deleted file mode 100644
index 0e88c57..0000000
--- a/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalBase.java
+++ /dev/null
@@ -1,250 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.seaborne.dboe.transaction.txn;
-
-import java.util.Objects ;
-
-import org.apache.jena.atlas.logging.Log ;
-import org.apache.jena.query.ReadWrite ;
-
-/**
- * Framework for implementing a Transactional.
- */
-
-public class TransactionalBase implements TransactionalSystem {
-    // Help debugging by generating names for Transactionals.
-    private final String label ; 
-    protected boolean isShutdown = false ; 
-    protected final TransactionCoordinator txnMgr ;
-    
-    // Per thread transaction.
-    private final ThreadLocal<Transaction> theTxn = new ThreadLocal<>() ;
-    
-    public TransactionalBase(String label, TransactionCoordinator txnMgr) {
-        this.label = label ;
-        this.txnMgr = txnMgr ;
-    }
-    
-    public TransactionalBase(TransactionCoordinator txnMgr) {
-        this(null, txnMgr) ;
-    }
-
-    @Override
-    public TransactionCoordinator getTxnMgr() {
-        return txnMgr ;
-    }
-
-    // Development
-    private static final boolean trackAttachDetach = false ;
-    
-    @Override
-    public TransactionCoordinatorState detach() {
-        if ( trackAttachDetach )
-            Log.info(this,  ">> detach");
-        checkRunning() ;
-        // Not if it just commited but before end.
-        //checkActive() ;
-        Transaction txn = theTxn.get() ;
-        TransactionCoordinatorState coordinatorState = null ;
-        if ( txn != null )
-            // We are not ending.
-            coordinatorState = txnMgr.detach(txn) ;
-        if ( trackAttachDetach )
-            Log.info(this,  "  theTxn = "+txn) ;
-        theTxn.remove() ; ///??????
-        if ( trackAttachDetach )
-            Log.info(this,  "<< detach");
-        if ( coordinatorState == null )
-            throw new TransactionException("Not attached") ;
-        return coordinatorState ;
-    }
-    
-    @Override
-    public void attach(TransactionCoordinatorState coordinatorState) {
-        if ( trackAttachDetach )
-            Log.info(this,  ">> attach");
-        Objects.nonNull(coordinatorState) ;
-        checkRunning() ;
-        checkNotActive() ;
-        TxnState txnState = coordinatorState.transaction.getState() ;
-        if ( txnState != TxnState.DETACHED )
-            throw new TransactionException("Not a detached transaction") ;
-        txnMgr.attach(coordinatorState) ;
-        if ( trackAttachDetach )
-            Log.info(this,  "  theTxn = "+coordinatorState.transaction) ;
-        theTxn.set(coordinatorState.transaction);
-        if ( trackAttachDetach )
-            Log.info(this,  "<< attach");
-    } 
-    
-    @Override
-    public final void begin(ReadWrite readWrite) {
-        Objects.nonNull(readWrite) ;
-        checkRunning() ;
-        checkNotActive() ;
-        Transaction transaction = txnMgr.begin(readWrite) ;
-        theTxn.set(transaction) ;
-    }
-    
-    @Override
-    public boolean promote() {
-        checkActive() ;
-        Transaction txn = getValidTransaction() ;
-        return txn.promote() ;
-    }
-
-    @Override
-    public final void commit() {
-        checkRunning() ;
-        TransactionalSystem.super.commit() ;
-    }
-
-    @Override
-    public void commitPrepare() {
-        Transaction txn = getValidTransaction() ;
-        txn.prepare() ;
-    }
-
-    @Override
-    public void commitExec() {
-        Transaction txn = getValidTransaction() ;
-        txn.commit() ;
-        _end() ;
-    }
-
-//    /** Signal end of commit phase */
-//    @Override
-//    public void commitEnd() {
-//        _end() ;
-//    }
-    
-    @Override
-    public final void abort() {
-        checkRunning() ;
-        checkActive() ;
-        Transaction txn = getValidTransaction() ;
-        try { txn.abort() ; }
-        finally { _end() ; }
-    }
-
-    @Override
-    public final void end() {
-        checkRunning() ;
-        // Don't check if active or if any thread locals exist
-        // because this may have already been called.
-        // txn.get() ; -- may be null -- test repeat calls.
-        _end() ;
-    }
-
-    /**
-     * Return the Read/write state (or null when not in a transaction)
-     */
-    @Override
-    final
-    public ReadWrite getState() {
-        checkRunning() ;
-        // tricky - touching theTxn causes it to initialize.
-        Transaction txn = theTxn.get() ;
-        if ( txn != null )
-            return txn.getMode() ;
-        theTxn.remove() ;
-        return null ; 
-    }
-    
-    @Override
-    final
-    public TransactionInfo getTransactionInfo() {
-        return getThreadTransaction() ;
-    }
-    
-    @Override
-    final
-    public Transaction getThreadTransaction() {
-        Transaction txn = theTxn.get() ;
-        // Touched the thread local so it is defined now.
-//        if ( txn == null )
-//            theTxn.remove() ;
-        return txn ;
-    }
-
-    /** Get the transaction, checking there is one */  
-    private Transaction getValidTransaction() {
-        Transaction txn = theTxn.get() ;
-        if ( txn == null )
-            throw new TransactionException("Not in a transaction") ;
-        return txn ;
-    }
-
-    private void checkRunning() {
-//        if ( ! hasStarted )
-//            throw new TransactionException("Not started") ;
-        
-        if ( isShutdown )
-            throw new TransactionException("Shutdown") ;
-    }
-    
-    /**
-     * Shutdown component, aborting any in-progress transactions. This operation
-     * is not guaranteed to be called.
-     */
-    public void shutdown() {
-        txnMgr.shutdown() ;
-        isShutdown = true ;
-    }
-
-    protected String label(String msg) {
-        if ( label == null )
-            return msg ;
-        return label+": "+msg ;
-    }
-    
-    final
-    protected void checkActive() {
-        checkNotShutdown() ;
-        if ( ! isInTransaction() )
-            throw new TransactionException(label("Not in an active transaction")) ;
-    }
-
-    final
-    protected void checkNotActive() {
-        checkNotShutdown() ;
-        if ( isInTransaction() )
-            throw new TransactionException(label("Currently in an active transaction")) ;
-    }
-
-    final
-    protected void checkNotShutdown() {
-        if ( isShutdown )
-            throw new TransactionException(label("Already shutdown")) ;
-    }
-
-    private final void _end() {
-        Transaction txn = theTxn.get() ;
-        if ( txn != null ) {
-            try {
-                // Can throw an exception on begin(W)...end().
-                txn.end() ;
-            } finally {
-                theTxn.set(null) ;
-                theTxn.remove() ;
-            }
-        }
-    }
-}
-

http://git-wip-us.apache.org/repos/asf/jena/blob/3d456654/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalComponent.java
----------------------------------------------------------------------
diff --git a/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalComponent.java b/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalComponent.java
deleted file mode 100644
index 5057ae6..0000000
--- a/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalComponent.java
+++ /dev/null
@@ -1,176 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.seaborne.dboe.transaction.txn;
-
-import java.nio.ByteBuffer ;
-
-/** Interface that for components of a transaction system.
-* <p><br/>
-* The {@link TransactionCoordinator} manages a number of components
-* which provide the {@link TransactionalComponent} interface.
-* <p><br/>
-* When a new coordinator starts, typically being when the in-process system starts,
-* there is a recovery phase when work from a previous coordinator is recovered.
-* Transactions were either were properly committed by the previous coordinator,
-* and hence redo actions (finalization) should be done,
-* or they were not, in which case undo actions may be needed.
-* Transctions to discard are not notified, only fully commited transaction are
-* notified during recovery. The component may need to keepit's own record of
-* undo actions needed across restarts.
-* <p><br/>
-* Lifecycle of startup:
-* <ul>
-* <li>{@link #startRecovery}
-* <li>{@link #recover} for each commited/durable transaction (redo actions)
-* <li>{@link #finishRecovery}, discarding any othe transactions (undo actions).
-* </ul>
-* <p><br/>
-* Lifecycle of a read transaction:
-* <ul>
-* <li>{@link #begin}
-* <li>{@link #complete}
-* </ul>
-* <br/>
-* A read transaction may also include {@code commit} or {@code abort} lifecycles.
-* {@link #commitPrepare} and {@link #commitEnd} are not called.
-*<p><br/>
-* Lifecycle of a write transaction:
-* <li>{@link #begin}
-* <li>{@link #commitPrepare}
-* <li>{@link #commit} or {@link #abort}
-* <li>{@link #commitEnd}
-* <li>{@link #complete} including abort
-* </ul>
-* <br/>
-* or if the application aborts the transaction:
-* <ul>
-* <li>{@link #begin}
-* <li>{@link #abort}
-* <li>{@link #complete}
-* </ul>
-* <p>
-* {@link #complete} may be called out of sequence and it forces an abort if before 
-* {@link #commitPrepare}. Once {@link #commitPrepare} has been called, the component
-* can not decide whether to commit finally or to cause a system abort; it must wait 
-* for the coordinator. After {@link #commitEnd}, the coordinator has definitely 
-* commited the overall transaction and local prepared state can be released, and changes
-* made to the permanent state of the component.
-*
-* @see Transaction
-* @see TransactionCoordinator
-*/
-
-public interface TransactionalComponent
-{
-    /**
-     * Every component <i>instance</i> must supplied a unique number.
-     * It is used to route journal entries to subsystems, including across restarts/recovery. 
-     * Uniqueness scope is within the same {@link TransactionCoordinator},
-     * and the same across restarts.  
-     * <p>
-     * If a component imposes the rule of one-per-{@link TransactionCoordinator},
-     * the same number can be used (if different from all other component type instances).
-     * <p>
-     * If a component can have multiple instances per {@link TransactionCoordinator},
-     * for example indexes, each must have a unique instance id. 
-     */
-    public ComponentId getComponentId() ;
-
-    // ---- Recovery phase
-    public void startRecovery() ;
-    
-    /** Notification that {@code ref} was really committed and is being recovered.
-     *  
-     * @param ref Same bytes as were written during prepare originally.
-     */
-    public void recover(ByteBuffer ref) ;
-    
-    /** End of the receovery phase */
-    public void finishRecovery() ;
-
-    /** Indicate that no recovery is being done (the journal thinks everything was completed last time) */
-    public void cleanStart() ;
-
-    // ---- Normal operation
-    
-    /** Start a transaction; return an identifier for this components use. */ 
-    public void begin(Transaction transaction) ;
-    
-    /** Promote a component in a transaction.
-     * <p>
-     *  May return "false" for "can't do that" if the transaction can not be promoted.
-     *  <p>
-     *  May throw {@link UnsupportedOperationException} if promotion is not supported.
-     */
-    public boolean promote(Transaction transaction) ;
-
-    /** Prepare for a commit.
-     *  Returns some bytes that will be written to the journal.
-     *  The journal remains valid until {@link #commitEnd} is called.
-     */
-    public ByteBuffer commitPrepare(Transaction transaction) ;
-
-    /** Commit a transaction (make durable).
-     * Other components not have been commited yet and recovery may occur still.
-     * Permanent state should not be finalised until {@link #commitEnd}.
-     */
-    public void commit(Transaction transaction) ;
-    
-    /** Signal all commits on all components are done (the component can clearup now) */  
-    public void commitEnd(Transaction transaction) ;
-
-    /** Abort a transaction (undo the effect of a transaction) */   
-    public void abort(Transaction transaction) ;
-
-    /** Finalization - the coordinator will not mention the transaction again
-     *  although recovery after a crash may do so.
-     */
-    public void complete(Transaction transaction) ;
-    
-    // ---- End of operations
-    
-    /** Detach this component from the transaction of the current thread
-     * and return some internal state that can be used in a future call of 
-     * {@link #attach(SysTransState)}
-     * <p>
-     * After this call, the component is not in a transaction but the
-     * existing transaction still exists. The thread may start a new
-     * transaction; that transaction is completely independent of the
-     * detached transaction.
-     * <p>
-     * Returns {@code null} if the current thread not in a transaction.
-     * The component may return null to indicate it has no state. 
-     * The return system state should be used in a call to {@link #attach(SysTransState)}
-     * and the transaction ended in the usual way. 
-     *   
-     */
-    public SysTransState detach() ;
-    
-    /** Set the current thread to be in the transaction.  The {@code systemState}
-     * must be obtained from a call of {@link #detach()}.
-     * This method can only be called once per {@code systemState}.
-     */
-    public void attach(SysTransState systemState) ;
-    
-    /** Shutdown component, aborting any in-progress transactions.
-     * This operation is not guaranteed to be called.
-     */
-    public void shutdown() ;
-    
-}

http://git-wip-us.apache.org/repos/asf/jena/blob/3d456654/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalComponentBase.java
----------------------------------------------------------------------
diff --git a/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalComponentBase.java b/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalComponentBase.java
deleted file mode 100644
index 8dc8530..0000000
--- a/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalComponentBase.java
+++ /dev/null
@@ -1,77 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.seaborne.dboe.transaction.txn;
-
-import java.nio.ByteBuffer ;
-
-import org.apache.jena.query.ReadWrite ;
-
-/**
- * A transaction component that does nothing - can be used as a helper for
- * management tasks hooked into the transaction component lifecycle but which
- * are not stateful across restarts.
- */
-public class TransactionalComponentBase<X> extends TransactionalComponentLifecycle<X> {
-    
-    public TransactionalComponentBase(ComponentId id) {
-        super(id) ;
-    }
-    
-    @Override
-    public void startRecovery() {}
-
-    @Override
-    public void recover(ByteBuffer ref) {}
-
-    @Override
-    public void finishRecovery() {}
-    
-    @Override 
-    public void cleanStart() {}
-
-    @Override
-    protected X _begin(ReadWrite readWrite, TxnId txnId) {
-        return null ;
-    }
-
-    @Override
-    protected ByteBuffer _commitPrepare(TxnId txnId, X state) {
-        return null ;
-    }
-
-    @Override
-    protected void _commit(TxnId txnId, X state) {}
-
-    @Override
-    protected void _commitEnd(TxnId txnId, X state) {}
-
-    @Override
-    protected void _abort(TxnId txnId, X state) {}
-
-    @Override
-    protected void _complete(TxnId txnId, X state) {}
-
-    @Override
-    protected void _shutdown() {}
-
-    @Override
-    protected X _promote(TxnId txnId, X state) { return null; }
-
-}
-

http://git-wip-us.apache.org/repos/asf/jena/blob/3d456654/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalComponentLifecycle.java
----------------------------------------------------------------------
diff --git a/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalComponentLifecycle.java b/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalComponentLifecycle.java
deleted file mode 100644
index f4aeb53..0000000
--- a/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalComponentLifecycle.java
+++ /dev/null
@@ -1,481 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.seaborne.dboe.transaction.txn;
-
-import static org.seaborne.dboe.transaction.txn.TxnState.* ;
-
-import java.nio.ByteBuffer ;
-import java.util.Objects ;
-
-import org.apache.jena.query.ReadWrite ;
-
-import org.apache.jena.atlas.lib.InternalErrorException ;
-
-/** 
- * Base implementation of the component interface for {@link TransactionalComponent}.
- */
-public abstract class TransactionalComponentLifecycle<X> implements TransactionalComponent {
-    
-    // Pass down recovery operations.
-    // This class has no transaction-recorded state.
-    @Override public abstract void startRecovery();
-    @Override public abstract void recover(ByteBuffer ref);
-    @Override public abstract void finishRecovery();
-    
-    // ---- Normal operation
-    
-    private static final boolean CHECKING = false ;
-    private ThreadLocal<TxnState> trackTxn = CHECKING ? ThreadLocal.withInitial(() -> INACTIVE) : null ; 
-    
-    // Access to these two must be via the getter/setters below only.
-    // Allows stuff for thread switching.
-    private ThreadLocal<Transaction> threadTxn = new ThreadLocal<>() ;
-    private ThreadLocal<X> componentState = new ThreadLocal<>() ;
-    private final ComponentId componentId ;
-    
-    protected TransactionalComponentLifecycle(ComponentId componentId) {
-        this.componentId = componentId ;
-    }
-    
-    @Override
-    public ComponentId getComponentId() {
-        return componentId ;
-    }
-
-//    // Very dangerous!
-//    protected void setForThread(Transaction txn, X state) {
-//        threadTxn.set(txn);
-//        componentState.set(state);
-//    }
-    
-    /** Start a transaction */
-    @Override
-    final
-    public void begin(Transaction transaction) {
-        Objects.requireNonNull(transaction) ;
-        setTransaction(transaction); 
-        checkState(INACTIVE, COMMITTED, ABORTED) ;
-        setTrackTxn(ACTIVE);
-        X x = _begin(transaction.getMode(), transaction.getTxnId()) ;
-        setDataState(x);
-    }
-    
-    /** Promote a component in a transaction */
-    @Override
-    final
-    public boolean promote(Transaction transaction) {
-        Objects.requireNonNull(transaction) ;
-        checkState(ACTIVE) ;
-        X newState = _promote(transaction.getTxnId(), getDataState());
-        if ( newState == null )
-            return false;
-        setDataState(newState);
-        return true;
-    }
-    
-    /** Commit a transaction (make durable): prepare - commit - cleanup */  
-    @Override
-    final
-    public ByteBuffer commitPrepare(Transaction transaction) {
-        checkAligned(transaction) ;
-        checkState(ACTIVE) ;
-        try { return _commitPrepare(transaction.getTxnId(), getDataState()) ; }
-        finally { setTrackTxn(PREPARE) ; }
-    }
-
-    @Override
-    final
-    public void commit(Transaction transaction) {
-        checkAligned(transaction) ;
-        checkState(PREPARE) ;
-        _commit(transaction.getTxnId(), getDataState());
-        setTrackTxn(COMMIT) ;
-    }
-    
-    @Override
-    final
-    public void commitEnd(Transaction transaction) {
-        checkAligned(transaction) ;
-        checkState(COMMIT) ;
-        _commitEnd(transaction.getTxnId(), getDataState());
-        setTrackTxn(COMMITTED) ;
-        internalComplete(transaction) ;
-    }
-
-    @Override 
-    final
-    public void abort(Transaction transaction) {
-        checkAligned(transaction) ;
-        checkState(ACTIVE, PREPARE, COMMIT) ;
-        _abort(transaction.getTxnId(), getDataState()) ;
-        setTrackTxn(ABORTED) ;
-        internalComplete(transaction) ;
-    }
-
-    private void internalComplete(Transaction transaction) {
-        _complete(transaction.getTxnId(), getDataState());
-        setTrackTxn(INACTIVE) ;
-        releaseThreadState() ;
-    }
-
-    @Override
-    final
-    public void complete(Transaction transaction) {
-        if ( transaction.hasFinished() )
-            return ;
-        checkAligned(transaction) ;
-        ReadWrite m = getReadWriteMode() ;
-        switch(m) {
-            case READ:
-                checkState(ACTIVE, COMMITTED, ABORTED) ;
-                break ;
-            case WRITE:
-                // If bad, force abort?
-                checkState(COMMITTED, ABORTED) ; 
-                break ;
-        }
-        _complete(transaction.getTxnId(), getDataState());
-        switch(m) {
-            case READ:
-                internalComplete(transaction);
-                break ;
-            case WRITE:
-                // complete happened in the commit or abort.
-                break ;
-        }
-    }
-    
-    @Override 
-    final
-    public void shutdown() {
-        _shutdown() ;
-        clearInternal() ;
-    }
-    
-    @Override 
-    final public SysTransState detach() {
-        TxnState txnState = getTxnState() ;
-        if ( txnState == null )
-            return null ;
-        checkState(ACTIVE) ;
-        setTrackTxn(DETACHED) ;
-        SysTransState transState = new SysTransState(this, getTransaction(), getDataState()) ;
-        //****** Thread locals 
-        releaseThreadState() ;
-        return transState ;
-    }
-    
-    @Override
-    public void attach(SysTransState state) {
-        @SuppressWarnings("unchecked")
-        X x = (X)state.getState() ;
-//        // reset to not thread not in 
-//        if ( CHECKING )
-//            trackTxn : ThreadLocal<TxnState>
-//        
-//      
-        setTransaction(state.getTransaction());
-        setDataState(x);
-        setTrackTxn(ACTIVE) ;
-    }
-    
-    // -- Access object members.
-
-    public static class ComponentState<X> {
-        final TxnState state;
-        final Transaction txn ;
-        final X componentState ;
-        ComponentState(TxnState state, Transaction txn, X componentState) {
-            super() ;
-            this.state = state ;
-            this.txn = txn ;
-            this.componentState = componentState ;
-        }
-    }
-    
-    public ComponentState<X> getComponentState() {
-        return new ComponentState<>(getTrackTxn(), getTransaction(), getDataState()) ; 
-    }
-    
-    public void setComponentState(ComponentState<X> state) {
-        setTrackTxn(state.state);
-        setTransaction(state.txn);
-        setDataState(state.componentState);
-        
-    }
-
-    protected void releaseThreadState() {
-        // Remove thread locals
-        if ( trackTxn != null )
-            trackTxn.remove() ;
-        componentState.remove();
-        
-//        java version "1.8.0_31"
-//        Java(TM) SE Runtime Environment (build 1.8.0_31-b13)
-//        Java HotSpot(TM) 64-Bit Server VM (build 25.31-b07, mixed mode)
-//        
-//        openjdk version "1.8.0_40-internal"
-//        OpenJDK Runtime Environment (build 1.8.0_40-internal-b09)
-//        OpenJDK 64-Bit Server VM (build 25.40-b13, mixed mode)
-        
-        // This one is very important else the memory usage grows.  Not clear why.
-        // A Transaction has an internal AtomicReference.  Replacing the AtomicReference
-        // with a plain member variable slows the growth down greatly.
-        threadTxn.remove() ;
-    }
-    
-    protected void clearInternal() {
-        trackTxn = null ;
-        threadTxn = null ;
-        componentState = null ;
-    }
-    
-    //protected ComponentState<X> getState()
-    
-    protected X getDataState()                      { return componentState.get() ; }
-    protected void setDataState(X data)             { componentState.set(data) ; }
-
-    protected Transaction getTransaction()          { return threadTxn.get(); }
-    protected void setTransaction(Transaction txn)  { threadTxn.set(txn); }
-    
-    private void setTrackTxn(TxnState newState) {
-        if ( ! CHECKING ) return ;
-        trackTxn.set(newState);
-    }
-
-    // This is our record of the state - it is not necessarily the transactions
-    // view during changes.  This class tracks the expected incomign state and
-    // the transaction
-    private TxnState getTrackTxn() {
-        if ( ! CHECKING ) return null ;
-        return trackTxn.get();
-    }
-    // -- Access object members.
-    
-    // XXX Align to javadoc in TransactionalComponent.
-    
-    /* There are two lifecycles, one for write transaction, one
-     * for read transactions. This affects how transaction end so
-     * when/if promoted read->write transactions happen, a promoted
-     * transaction will follow the write lifecycle. 
-     * 
-     * In both lifecyles, the implementer can assume that calls
-     * happen at the right points and called only as needed.  Framework
-     * takes care of checking.  
-     * 
-     * Read lifecycle:
-     * A read transaction be be just begin(READ)-end() but may also
-     * have commit or abort before end. The _commitRead and _abortRead
-     * calls note if an explicit commit or abort occurs but may not be
-     * called. _endRead is always called exactly once.
-     *  
-     * _commitRead
-     * _abortRead
-     * _endRead
-     * _complete
-     * 
-     * Write lifecycle:
-     * A write transaction must have a commit() or abort() before end().
-     * The fraemwork will check this.
-     * 
-     * If the transaction commits:
-     * _commitPrepareWrite
-     * _commitWrite -- The transaction is 
-     * _commitEndWrite
-     * 
-     * If the transaction aborts:
-     * _abortWrite
-     * 
-     * After any lifecycle, a final call of
-     * _complete()
-     * 
-     * indicates ths transaction has fully finished.
-     * 
-     * Typically, an implementation does not need to take action in every call. 
-     */
-    
-//    /**
-//     * 
-//     * @param readWrite
-//     * @param txnId
-//     * @return
-//     */
-//    protected abstract X           _begin(ReadWrite readWrite, TxnId txnId) ;
-//    
-//    /**
-//     * 
-//     * @param txnId
-//     * @param state
-//     * @return
-//     */
-//    protected abstract ByteBuffer  _commitPrepareWrite(TxnId txnId, X  state) ;
-//    
-//    /**
-//     * 
-//     * @param txnId
-//     * @param state
-//     */
-//    protected abstract void        _commitWrite(TxnId txnId, X state) ;
-//    
-//    /**
-//     * 
-//     * @param txnId
-//     * @param state
-//     */
-//    protected abstract void        _commitEndWrite(TxnId txnId, X state) ;
-//    
-//    /**
-//     * 
-//     * @param txnId
-//     * @param state
-//     */
-//    protected abstract void        _abortWrite(TxnId txnId, X state) ;
-//    
-//    /**
-//     * 
-//     * @param txnId
-//     * @param state
-//     * @return
-//     */
-//    protected abstract ByteBuffer  _commitRead(TxnId txnId, X  state) ;
-//    
-//    /**
-//     * 
-//     * @param txnId
-//     * @param state
-//     * @return
-//     */
-//    protected abstract ByteBuffer  _abortRead(TxnId txnId, X  state) ;
-//
-//    /**
-//     * 
-//     * @param txnId
-//     * @param state
-//     */
-//    protected abstract void        _complete(TxnId txnId, X state) ;
-//    
-//    /**
-//     * 
-//     */
-//    protected abstract void        _shutdown() ;
-
-    protected abstract X           _begin(ReadWrite readWrite, TxnId txnId) ;
-    protected abstract X           _promote(TxnId txnId, X oldState) ;
-    protected abstract ByteBuffer  _commitPrepare(TxnId txnId, X  state) ;
-    protected abstract void        _commit(TxnId txnId, X state) ;
-    protected abstract void        _commitEnd(TxnId txnId, X state) ;
-    protected abstract void        _abort(TxnId txnId, X state) ;
-    protected abstract void        _complete(TxnId txnId, X state) ;
-    protected abstract void        _shutdown() ;
-    
-    protected ReadWrite getReadWriteMode() {
-        Transaction txn = getTransaction() ;
-        return txn.getMode() ;
-    }
-    
-    protected boolean isActiveTxn() {
-        TxnState txnState = getTxnState() ;
-        if ( txnState == null )
-            return false ; 
-        switch(getTxnState()) {
-            case INACTIVE: case END_ABORTED: case END_COMMITTED: 
-                return false ;
-            case ACTIVE: case DETACHED: case PREPARE: case ABORTED: case COMMIT: case COMMITTED:  
-                return true ;
-            //null: default: return false ;
-            // Get the compiler to check all states covered.
-        }
-        // Should not happen.
-        throw new InternalErrorException("Unclear transaction state") ;
-    }
-
-    protected boolean isReadTxn() { return ! isWriteTxn() ; }
-    
-    protected boolean isWriteTxn() {
-        Transaction txn = getTransaction();
-        return txn.isWriteTxn() ;
-    }
-    
-    protected void checkTxn() {
-        if ( ! isActiveTxn() )
-            throw new TransactionException("Not in a transaction") ;
-    }
-
-//    protected void requireWriteTxn() {
-//        Transaction txn = getTransaction();
-//        if ( txn == null )
-//            throw new TransactionException("Not a transaction");
-//        else 
-//            txn.requireWriteTxn() ;
-//    }
-    
-    protected void checkWriteTxn() {
-        Transaction txn = getTransaction();
-        if ( txn == null )
-            throw new TransactionException("Not a transaction");
-        else 
-            txn.requireWriteTxn() ;
-    }
-
-    // -- Access object members.
-    
-    private TxnState getTxnState() { 
-        Transaction txn = getTransaction() ;
-        if ( txn == null )
-            return null ;
-        return txn.getState() ;
-    }
-
-    private void checkAligned(Transaction transaction) {
-        if ( ! CHECKING ) return ;
-        Transaction txn = getTransaction();
-        if ( txn != transaction )
-            throw new TransactionException("Transaction is not the transaction of the thread") ; 
-    }
-    
-    private void checkState(TxnState expected) {
-        if ( ! CHECKING ) return ;
-        TxnState s = getTrackTxn() ;
-        if ( s != expected )
-            throw new TransactionException("Transaction is in state "+s+": expected state "+expected) ;
-    }
-
-    private void checkState(TxnState expected1, TxnState expected2) {
-        if ( ! CHECKING ) return ;
-        TxnState s = getTrackTxn() ;
-        if ( s != expected1 && s != expected2 )
-            throw new TransactionException("Transaction is in state "+s+": expected state "+expected1+" or "+expected2) ;
-    }
-
-    // Avoid varargs ... undue worry?
-    private void checkState(TxnState expected1, TxnState expected2, TxnState expected3) {
-        if ( ! CHECKING ) return ;
-        TxnState s = getTrackTxn() ;
-        if ( s != expected1 && s != expected2 && s != expected3 )
-            throw new TransactionException("Transaction is in state "+s+": expected state "+expected1+", "+expected2+" or "+expected3) ;
-    }
-
-    //    private void checkStateNot(State unexpected) {
-//        State s = state.get();
-//        if ( s == unexpected )
-//            throw new TransactionException("Transaction in unexpected state "+s) ;
-//    }
-
-}
-

http://git-wip-us.apache.org/repos/asf/jena/blob/3d456654/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalComponentWrapper.java
----------------------------------------------------------------------
diff --git a/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalComponentWrapper.java b/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalComponentWrapper.java
deleted file mode 100644
index a07852e..0000000
--- a/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalComponentWrapper.java
+++ /dev/null
@@ -1,108 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.seaborne.dboe.transaction.txn ;
-
-import java.nio.ByteBuffer ;
-
-public class TransactionalComponentWrapper implements TransactionalComponent {
-    protected final TransactionalComponent other ;
-
-    public TransactionalComponentWrapper(TransactionalComponent other) {
-        this.other = other ;
-    }
-
-    @Override
-    public void startRecovery() {
-        other.startRecovery() ;
-    }
-
-    @Override
-    public void recover(ByteBuffer ref) {
-        other.recover(ref) ;
-    }
-
-    @Override
-    public void finishRecovery() {
-        other.finishRecovery() ;
-    }
-    
-    @Override
-    public void cleanStart() {
-        other.cleanStart() ;
-    }
-
-    @Override
-    public ComponentId getComponentId() {
-        return other.getComponentId() ;
-    }
-
-    @Override
-    public void begin(Transaction transaction) {
-        other.begin(transaction) ;
-    }
-
-    @Override
-    public boolean promote(Transaction transaction) {
-        return other.promote(transaction) ;
-    }
-
-    @Override
-    public ByteBuffer commitPrepare(Transaction transaction) {
-        return other.commitPrepare(transaction) ;
-    }
-
-    @Override
-    public void commit(Transaction transaction) {
-        other.commit(transaction) ;
-    }
-
-    @Override
-    public void commitEnd(Transaction transaction) {
-        other.commitEnd(transaction) ;
-    }
-
-    @Override
-    public void abort(Transaction transaction) {
-        other.abort(transaction) ;
-    }
-
-    @Override
-    public void complete(Transaction transaction) {
-        other.complete(transaction) ;
-    }
-
-    @Override
-    public SysTransState detach() {
-        return other.detach() ;
-    }
-
-    @Override
-    public void attach(SysTransState systemState) {
-        other.attach(systemState) ;
-    }
-
-    @Override
-    public void shutdown() {
-        other.shutdown() ;
-    }
-
-    @Override 
-    public String toString() { return "W:"+other.toString() ; }
-}
-

http://git-wip-us.apache.org/repos/asf/jena/blob/3d456654/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalMRSW.java
----------------------------------------------------------------------
diff --git a/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalMRSW.java b/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalMRSW.java
deleted file mode 100644
index 920ee05..0000000
--- a/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalMRSW.java
+++ /dev/null
@@ -1,137 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.seaborne.dboe.transaction.txn;
-
-import java.nio.ByteBuffer ;
-import java.util.concurrent.locks.Lock ;
-import java.util.concurrent.locks.ReadWriteLock ;
-import java.util.concurrent.locks.ReentrantReadWriteLock ;
-
-import org.apache.jena.atlas.logging.Log ;
-
-import org.apache.jena.query.ReadWrite ;
-
-/** Implementation of the component interface for {@link TransactionalComponent}.
- *  Useful for in-memory transactions that do not provide durability or abort (undo). 
- *  When retro fitting to other systems, that may be the best that can be done. 
- */
-public class TransactionalMRSW extends TransactionalComponentLifecycle<Object> {
-    // MRSW implementation of TransactionMVCC
-    // XXX Update to Jena style TransactionalLock
-    private ReadWriteLock lock = new ReentrantReadWriteLock() ;
-    
-    public TransactionalMRSW(ComponentId componentId) {
-        super(componentId) ;
-    }
-
-    // ---- Recovery phase
-    @Override
-    public void startRecovery() {}
-    
-    @Override
-    public void recover(ByteBuffer ref) {
-        Log.warn(this, "Called to recover a transaction (ignored)") ; 
-    }
-
-    @Override
-    public void finishRecovery() { }
-    
-    @Override 
-    public void cleanStart() {}
-    
-    private Lock getLock() {
-        return ( ReadWrite.WRITE.equals(getReadWriteMode()) ) ? lock.writeLock() : lock.readLock() ;
-    }
-    
-    @Override
-    protected Object _begin(ReadWrite readWrite, TxnId thisTxnId) {
-        Lock lock = getLock() ;
-        // This is the point that makes this MRSW (readers OR writer), not MR+SW (readers and a writer)
-        lock.lock();
-        if ( isWriteTxn() )
-            startWriteTxn(); 
-        else 
-            startReadTxn(); 
-        return createState();                    
-    }
-
-    private Object createState() {
-        return new Object();
-    }
-    
-    @Override
-    protected Object _promote(TxnId txnId, Object state) {
-        // We have a read lock, the transaction coordinator has said 
-        // it's OK (from it's point-of-view) to promote so this should succeed.
-        // We have a read lock - theer are no other writers.
-        boolean b = lock.writeLock().tryLock();
-        if ( ! b ) {
-            Log.warn(this, "Failed to promote");  
-            return false;
-        }
-        lock.readLock().unlock(); 
-        return createState(); 
-    }
-
-    // Checks.
-    
-    protected void startReadTxn()   {}
-    protected void startWriteTxn()  {}
-    protected void finishReadTxn()  {}
-    protected void finishWriteTxn() {}
-
-    @Override
-    protected ByteBuffer _commitPrepare(TxnId txnId, Object obj) {
-        return null ;
-    }
-
-    @Override
-    protected void _commit(TxnId txnId, Object obj) {
-        clearup() ;
-    }
-
-    @Override
-    protected void _commitEnd(TxnId txnId, Object obj) {
-        clearup() ;
-    }
-
-    @Override
-    protected void _abort(TxnId txnId, Object obj) {
-        clearup() ;
-    }
-
-    @Override
-    protected void _complete(TxnId txnId, Object obj) {
-    }
-
-    @Override
-    protected void _shutdown() {
-        lock = null ;
-    }
-
-    private void clearup() {
-        Lock lock = getLock() ;
-        if ( isWriteTxn() )
-            finishWriteTxn(); 
-        else 
-            finishReadTxn(); 
-        lock.unlock(); 
-    }
-}
-

http://git-wip-us.apache.org/repos/asf/jena/blob/3d456654/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalSystem.java
----------------------------------------------------------------------
diff --git a/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalSystem.java b/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalSystem.java
deleted file mode 100644
index 9b64799..0000000
--- a/jena-db/jena-dboe-transaction/src/main/java/org/seaborne/dboe/transaction/txn/TransactionalSystem.java
+++ /dev/null
@@ -1,83 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.seaborne.dboe.transaction.txn;
-
-import org.apache.jena.query.ReadWrite ;
-import org.seaborne.dboe.transaction.Transactional ;
-
-/** Implementation side of a {@link Transactional}.
- *  {@link Transactional} presents the application facing view
- *  whereas this has all the possible steps of an implementation.  
- *  Normally, the implementation of {@link #commit} is split up.
- */
-public interface TransactionalSystem extends Transactional {
-    
-    @Override
-    public default void commit() {
-        commitPrepare() ;
-        commitExec() ;
-    }
-    
-    /** Do the 2-phase "prepare" step after which
-     *  the transaction coordinator decides whether to commit
-     *  or abort.  A TransactionalSystem must be prepared for
-     *  both possibilities.   
-     */
-    public void commitPrepare();
-
-    /** Do the 2-phase "commit" step */
-    public void commitExec();
-
-    /** Suspend this transaction, detaching from the current thread.
-     * A new transaction on this thread can performed but the detached
-     * transaction still exists and if it is a write transaction
-     * it can still block other write transactions.
-     */
-    public TransactionCoordinatorState detach() ;
-    
-    /** 
-     * Attach a transaction to this thread.
-     * A transaction system implementation usually imposes a rule that 
-     * only one thread can have a transaction attached at a time. 
-     */
-    public void attach(TransactionCoordinatorState coordinatorState) ;
-
-    /** Get the associated {@link TransactionCoordinator} */
-    public TransactionCoordinator getTxnMgr() ; 
-    
-    /**  Return the Read/Write state from the point of view of the caller.
-     * Return null when not in a transaction.
-     */
-    public ReadWrite getState() ;
-    
-    @Override
-    public default boolean isInTransaction() { return getState() != null ; }  
-    
-    /** Return an information view of the transaction for this thread, if any.
-     *  Returns null when there is no active transaction for this tread. 
-     */
-    public TransactionInfo getTransactionInfo() ;
-    
-    /** Return the transaction object for this thread.  
-     *  Low-level use only.
-     *  To get information about the current transaction, call {@link #getTransactionInfo}.
-     */
-    public Transaction getThreadTransaction() ;
-}
-


Mime
View raw message