jena-db/jena-dboe-transaction/src/main/java/org/apache/jena/dboe/transaction/txn/Transaction.java - jena - Git at Google

 /*
  * 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.apache.jena.dboe.transaction.txn;

 import static org.apache.jena.dboe.transaction.txn.TxnState.ABORTED;
 import static org.apache.jena.dboe.transaction.txn.TxnState.ACTIVE;
 import static org.apache.jena.dboe.transaction.txn.TxnState.COMMIT;
 import static org.apache.jena.dboe.transaction.txn.TxnState.COMMITTED;
 import static org.apache.jena.dboe.transaction.txn.TxnState.DETACHED;
 import static org.apache.jena.dboe.transaction.txn.TxnState.END_ABORTED;
 import static org.apache.jena.dboe.transaction.txn.TxnState.END_COMMITTED;
 import static org.apache.jena.dboe.transaction.txn.TxnState.INACTIVE;
 import static org.apache.jena.dboe.transaction.txn.TxnState.PREPARE;

 import java.util.List;
 import java.util.Objects;
 import java.util.concurrent.atomic.AtomicReference;

 import org.apache.jena.query.ReadWrite;
 import org.apache.jena.query.TxnType;

 /**
  * A transaction as the composition of actions on components.
  * Works in conjunction with the TransactionCoordinator
  * to provide the transaction lifecycle.
  * @see TransactionCoordinator
  * @see TransactionalComponent
  */
 final
 public class Transaction implements TransactionInfo {
     // Using an AtomicReference<TxnState> requires that
     // TransactionalComponentLifecycle.internalComplete
     // frees the thread local for the threadTxn, otherwise memory
     // usage grows. If a plain member variable is used slow growth
     // is still seen.
     // Nulling txnMgr and clearing components stops that slow growth.

     private TransactionCoordinator txnMgr;
     private final TxnId txnId;
     private final List<SysTrans> components;

     // Using an AtomicReference makes this observable from the outside.
     // It also allow for multithreaded transactions (later).
     private final AtomicReference<TxnState> state = new AtomicReference<>();
     //private TxnState state;
     private final long dataVersion;
     private final TxnType txnType;
     private ReadWrite mode;

     public Transaction(TransactionCoordinator txnMgr, TxnType txnType, ReadWrite readWrite, TxnId txnId, long dataVersion, List<SysTrans> components) {
         Objects.requireNonNull(txnMgr);
         Objects.requireNonNull(txnId);
         Objects.requireNonNull(readWrite);
         Objects.requireNonNull(components);
         this.txnMgr = txnMgr;
         this.txnId = txnId;
         this.txnType = txnType;
         this.mode = readWrite;
         this.dataVersion = dataVersion;
         this.components = components;
         setState(INACTIVE);
     }

 //    /*package*/ void resetDataVersion(long dataVersion) {
 //        this.dataVersion = dataVersion;
 //    }

     /*package*/ void setState(TxnState newState) {
         state.set(newState);
     }

     @Override
     public TxnState getState() {
         return state.get();
     }

     /**
      * 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.
      */
     @Override
     public long getDataVersion() {
         return dataVersion;
     }

     public void begin() {
         checkState(INACTIVE);
         components.forEach((c) -> c.begin());
         setState(ACTIVE);
     }

     private boolean promoteReadCommitted() {
         if ( txnType == TxnType.READ_COMMITTED_PROMOTE ) return true;
         if ( txnType == TxnType.READ_PROMOTE ) return false;
         return false;
     }

     public boolean promote() {
         return promote(promoteReadCommitted());
     }

     public boolean promote(boolean readCommitted) {
         checkState(ACTIVE);
         if ( txnType == TxnType.READ )
             return false;
         boolean b = txnMgr.executePromote(this, readCommitted);
         if ( !b )
             return false;
         mode = ReadWrite.WRITE;
         return true;
     }

     /*package*/ void promoteComponents() {
         // Call back from the Transaction coordinator during promote.
         components.forEach((c) -> {
             if ( ! c.promote() )
                 throw new TransactionException("Failed to promote");
         });
         mode = ReadWrite.WRITE;
     }

     public void notifyUpdate() {
         checkState(ACTIVE);
         if ( mode == ReadWrite.READ ) {
             promote(promoteReadCommitted());
             mode = ReadWrite.WRITE;
         }
     }

     public void prepare() {
         checkState(ACTIVE);
         if ( mode == ReadWrite.WRITE )
             txnMgr.executePrepare(this);
         setState(PREPARE);
     }

     public void commit() {
         // The commit point is in TransactionCoordinator.executeCommit().
         TxnState s = getState();
         if ( s == ACTIVE )
             // Auto exec prepare().
             prepare();
         checkState(PREPARE);
         setState(COMMIT);
         // Sys abort -> state?
         switch(mode) {
             case WRITE:
                 txnMgr.executeCommit(this,
                                      ()->{components.forEach((c) -> c.commit()); } ,
                                      ()->{components.forEach((c) -> c.commitEnd()); },
                                      ()->{components.forEach((c) -> c.abort()); }
                                     );
                 break;
             case READ:
                 // Different lifecycle?
                 txnMgr.executeCommit(this,
                                      ()->{components.forEach((c) -> c.commit()); } ,
                                      ()->{components.forEach((c) -> c.commitEnd()); } ,
                                      ()->{components.forEach((c) -> c.abort()); }
                                     );
                 break;
         }
         setState(COMMITTED);
         endInternal();
     }

     public void abort() {
         abort$();
         endInternal();
     }

     private void abort$() {
         // Split into READ and WRITE forms.
         checkState(ACTIVE, ABORTED);
         // Includes notification start/finish
         txnMgr.executeAbort(this, ()-> { components.forEach((c) -> c.abort()); }) ;
         setState(ABORTED);
     }

     public void end() {
         // [1746]
         // txnMgr.executeEnd(thus, ()->{});
         txnMgr.notifyEndStart(this);
         if ( isWriteTxn() && getState() == ACTIVE ) {
             //Log.warn(this, "Write transaction with no commit() or abort() before end()");
             // Just abort process.
             abort$();
             endInternal();
             throw new TransactionException("Write transaction with no commit() or abort() before end() - forced abort");
         }
         endInternal();
         txnMgr.notifyEndFinish(this);
         txnMgr = null;
         //components.clear();
     }

     private void endInternal() {
         if ( hasFinalised() )
             return;
         // Called once, at the first abort/commit/end.
         txnMgr.notifyCompleteStart(this);
         components.forEach((c) -> c.complete());
         txnMgr.completed(this);
         if ( getState() == COMMITTED )
             setState(END_COMMITTED);
         else
             setState(END_ABORTED);
         txnMgr.notifyCompleteFinish(this);
     }

     /*package*/ List<SysTrans> getComponents() {
         return components;
     }

     /*package*/ void detach() {
         checkState(ACTIVE,PREPARE);
         setState(DETACHED);
     }

     /*package*/ void attach() {
         checkState(DETACHED);
         setState(ACTIVE);
     }

     /** Require a WRITE transaction - do not try to promote. */
     public void requireWriteTxn() {
         checkState(ACTIVE);
         if ( mode != ReadWrite.WRITE )
             throw new TransactionException("Not a write transaction");
     }

     /** Require a WRITE transaction - includes trying to promote. */
     public void ensureWriteTxn() {
         checkState(ACTIVE);
         if ( mode != ReadWrite.WRITE ) {
             boolean b = this.promote();
             if ( ! b )
                 throw new TransactionException("Can't become a write transaction");
         }
     }

     @Override
     public boolean hasStarted()   {
         TxnState x = getState();
         return x == INACTIVE;
     }

     @Override
     public boolean hasFinished() {
         TxnState x = getState();
         return x == COMMITTED || x == ABORTED || x == END_COMMITTED || x == END_ABORTED;
     }

     @Override
     public boolean hasFinalised() {
         TxnState x = getState();
         return x == END_COMMITTED || x == END_ABORTED;
     }

     @Override
     public TxnId getTxnId()         { return txnId; }

     @Override
     public TxnType   getTxnType()   { return txnType; }

     @Override
     public ReadWrite getMode()      { return mode; }

     /** Is this a READ transaction?
      * Convenience operation equivalent to {@code (getMode() == READ)}
      */
     @Override
     public boolean isReadTxn()  { return mode == ReadWrite.READ; }

     /** Is this a WRITE transaction?
      * Convenience operation equivalent to {@code (getMode() == WRITE)}
      */
     @Override
     public boolean isWriteTxn()  { return mode == ReadWrite.WRITE; }

     // hashCode/equality
     // These must be object equality.  No two transactions objects are .equals unless they are ==

     private void checkWriteTxn() {
         if ( ! isActiveTxn() || ! isWriteTxn() )
             throw new TransactionException("Not in a write transaction");
     }

     // XXX Duplicate -- TransactionalComponentLifecycle
     private void checkState(TxnState expected) {
         TxnState s = getState();
         if ( s != expected )
             throw new TransactionException("Transaction is in state "+s+": expected state "+expected);
     }

     private void checkState(TxnState expected1, TxnState expected2) {
         TxnState s = getState();
         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) {
         TxnState s = getState();
         if ( s != expected1 && s != expected2 && s != expected3 )
             throw new TransactionException("Transaction is in state "+s+": expected state "+expected1+", "+expected2+" or "+expected3);
     }

     @Override
     public boolean isActiveTxn() {
         return getState() != INACTIVE;
     }
 }
	/*
	* 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.apache.jena.dboe.transaction.txn;

	import static org.apache.jena.dboe.transaction.txn.TxnState.ABORTED;
	import static org.apache.jena.dboe.transaction.txn.TxnState.ACTIVE;
	import static org.apache.jena.dboe.transaction.txn.TxnState.COMMIT;
	import static org.apache.jena.dboe.transaction.txn.TxnState.COMMITTED;
	import static org.apache.jena.dboe.transaction.txn.TxnState.DETACHED;
	import static org.apache.jena.dboe.transaction.txn.TxnState.END_ABORTED;
	import static org.apache.jena.dboe.transaction.txn.TxnState.END_COMMITTED;
	import static org.apache.jena.dboe.transaction.txn.TxnState.INACTIVE;
	import static org.apache.jena.dboe.transaction.txn.TxnState.PREPARE;

	import java.util.List;
	import java.util.Objects;
	import java.util.concurrent.atomic.AtomicReference;

	import org.apache.jena.query.ReadWrite;
	import org.apache.jena.query.TxnType;

	/**
	* A transaction as the composition of actions on components.
	* Works in conjunction with the TransactionCoordinator
	* to provide the transaction lifecycle.
	* @see TransactionCoordinator
	* @see TransactionalComponent
	*/
	final
	public class Transaction implements TransactionInfo {
	// Using an AtomicReference<TxnState> requires that
	// TransactionalComponentLifecycle.internalComplete
	// frees the thread local for the threadTxn, otherwise memory
	// usage grows. If a plain member variable is used slow growth
	// is still seen.
	// Nulling txnMgr and clearing components stops that slow growth.

	private TransactionCoordinator txnMgr;
	private final TxnId txnId;
	private final List<SysTrans> components;

	// Using an AtomicReference makes this observable from the outside.
	// It also allow for multithreaded transactions (later).
	private final AtomicReference<TxnState> state = new AtomicReference<>();
	//private TxnState state;
	private final long dataVersion;
	private final TxnType txnType;
	private ReadWrite mode;

	public Transaction(TransactionCoordinator txnMgr, TxnType txnType, ReadWrite readWrite, TxnId txnId, long dataVersion, List<SysTrans> components) {
	Objects.requireNonNull(txnMgr);
	Objects.requireNonNull(txnId);
	Objects.requireNonNull(readWrite);
	Objects.requireNonNull(components);
	this.txnMgr = txnMgr;
	this.txnId = txnId;
	this.txnType = txnType;
	this.mode = readWrite;
	this.dataVersion = dataVersion;
	this.components = components;
	setState(INACTIVE);
	}

	// /package/ void resetDataVersion(long dataVersion) {
	// this.dataVersion = dataVersion;
	// }

	/package/ void setState(TxnState newState) {
	state.set(newState);
	}

	@Override
	public TxnState getState() {
	return state.get();
	}

	/**
	* 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.
	*/
	@Override
	public long getDataVersion() {
	return dataVersion;
	}

	public void begin() {
	checkState(INACTIVE);
	components.forEach((c) -> c.begin());
	setState(ACTIVE);
	}

	private boolean promoteReadCommitted() {
	if ( txnType == TxnType.READ_COMMITTED_PROMOTE ) return true;
	if ( txnType == TxnType.READ_PROMOTE ) return false;
	return false;
	}

	public boolean promote() {
	return promote(promoteReadCommitted());
	}

	public boolean promote(boolean readCommitted) {
	checkState(ACTIVE);
	if ( txnType == TxnType.READ )
	return false;
	boolean b = txnMgr.executePromote(this, readCommitted);
	if ( !b )
	return false;
	mode = ReadWrite.WRITE;
	return true;
	}

	/package/ void promoteComponents() {
	// Call back from the Transaction coordinator during promote.
	components.forEach((c) -> {
	if ( ! c.promote() )
	throw new TransactionException("Failed to promote");
	});
	mode = ReadWrite.WRITE;
	}

	public void notifyUpdate() {
	checkState(ACTIVE);
	if ( mode == ReadWrite.READ ) {
	promote(promoteReadCommitted());
	mode = ReadWrite.WRITE;
	}
	}

	public void prepare() {
	checkState(ACTIVE);
	if ( mode == ReadWrite.WRITE )
	txnMgr.executePrepare(this);
	setState(PREPARE);
	}

	public void commit() {
	// The commit point is in TransactionCoordinator.executeCommit().
	TxnState s = getState();
	if ( s == ACTIVE )
	// Auto exec prepare().
	prepare();
	checkState(PREPARE);
	setState(COMMIT);
	// Sys abort -> state?
	switch(mode) {
	case WRITE:
	txnMgr.executeCommit(this,
	()->{components.forEach((c) -> c.commit()); } ,
	()->{components.forEach((c) -> c.commitEnd()); },
	()->{components.forEach((c) -> c.abort()); }
	);
	break;
	case READ:
	// Different lifecycle?
	txnMgr.executeCommit(this,
	()->{components.forEach((c) -> c.commit()); } ,
	()->{components.forEach((c) -> c.commitEnd()); } ,
	()->{components.forEach((c) -> c.abort()); }
	);
	break;
	}
	setState(COMMITTED);
	endInternal();
	}

	public void abort() {
	abort$();
	endInternal();
	}

	private void abort$() {
	// Split into READ and WRITE forms.
	checkState(ACTIVE, ABORTED);
	// Includes notification start/finish
	txnMgr.executeAbort(this, ()-> { components.forEach((c) -> c.abort()); }) ;
	setState(ABORTED);
	}

	public void end() {
	// [1746]
	// txnMgr.executeEnd(thus, ()->{});
	txnMgr.notifyEndStart(this);
	if ( isWriteTxn() && getState() == ACTIVE ) {
	//Log.warn(this, "Write transaction with no commit() or abort() before end()");
	// Just abort process.
	abort$();
	endInternal();
	throw new TransactionException("Write transaction with no commit() or abort() before end() - forced abort");
	}
	endInternal();
	txnMgr.notifyEndFinish(this);
	txnMgr = null;
	//components.clear();
	}

	private void endInternal() {
	if ( hasFinalised() )
	return;
	// Called once, at the first abort/commit/end.
	txnMgr.notifyCompleteStart(this);
	components.forEach((c) -> c.complete());
	txnMgr.completed(this);
	if ( getState() == COMMITTED )
	setState(END_COMMITTED);
	else
	setState(END_ABORTED);
	txnMgr.notifyCompleteFinish(this);
	}

	/package/ List<SysTrans> getComponents() {
	return components;
	}

	/package/ void detach() {
	checkState(ACTIVE,PREPARE);
	setState(DETACHED);
	}

	/package/ void attach() {
	checkState(DETACHED);
	setState(ACTIVE);
	}

	/** Require a WRITE transaction - do not try to promote. */
	public void requireWriteTxn() {
	checkState(ACTIVE);
	if ( mode != ReadWrite.WRITE )
	throw new TransactionException("Not a write transaction");
	}

	/** Require a WRITE transaction - includes trying to promote. */
	public void ensureWriteTxn() {
	checkState(ACTIVE);
	if ( mode != ReadWrite.WRITE ) {
	boolean b = this.promote();
	if ( ! b )
	throw new TransactionException("Can't become a write transaction");
	}
	}

	@Override
	public boolean hasStarted() {
	TxnState x = getState();
	return x == INACTIVE;
	}

	@Override
	public boolean hasFinished() {
	TxnState x = getState();
	return x == COMMITTED \|\| x == ABORTED \|\| x == END_COMMITTED \|\| x == END_ABORTED;
	}

	@Override
	public boolean hasFinalised() {
	TxnState x = getState();
	return x == END_COMMITTED \|\| x == END_ABORTED;
	}

	@Override
	public TxnId getTxnId() { return txnId; }

	@Override
	public TxnType getTxnType() { return txnType; }

	@Override
	public ReadWrite getMode() { return mode; }

	/** Is this a READ transaction?
	* Convenience operation equivalent to {@code (getMode() == READ)}
	*/
	@Override
	public boolean isReadTxn() { return mode == ReadWrite.READ; }

	/** Is this a WRITE transaction?
	* Convenience operation equivalent to {@code (getMode() == WRITE)}
	*/
	@Override
	public boolean isWriteTxn() { return mode == ReadWrite.WRITE; }

	// hashCode/equality
	// These must be object equality. No two transactions objects are .equals unless they are ==

	private void checkWriteTxn() {
	if ( ! isActiveTxn() \|\| ! isWriteTxn() )
	throw new TransactionException("Not in a write transaction");
	}

	// XXX Duplicate -- TransactionalComponentLifecycle
	private void checkState(TxnState expected) {
	TxnState s = getState();
	if ( s != expected )
	throw new TransactionException("Transaction is in state "+s+": expected state "+expected);
	}

	private void checkState(TxnState expected1, TxnState expected2) {
	TxnState s = getState();
	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) {
	TxnState s = getState();
	if ( s != expected1 && s != expected2 && s != expected3 )
	throw new TransactionException("Transaction is in state "+s+": expected state "+expected1+", "+expected2+" or "+expected3);
	}

	@Override
	public boolean isActiveTxn() {
	return getState() != INACTIVE;
	}
	}