TxWrapper (P2J - Progress 4GL to Java Conversion and Runtime)

java.lang.Object
- com.goldencode.p2j.persist.TxWrapper

All Implemented Interfaces:

Commitable, Finalizable
```
class TxWrapper
extends java.lang.Object
implements Commitable, Finalizable
```
An object which manages the "master" Commitable and Finalizable events of an application transaction. It creates a database transaction to correspond with the application transaction, and as it receives events from the TransactionManager, it delegates related responsibilities to various components of the persistence framework.

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`(package private) static class`	`TxWrapper.AggresiveFlushWrapper` A proxy for a `Commitable` that suppressed the commits and rollbacks.
`(package private) static class`	`TxWrapper.TxWrapperHelper` Helper instance to access the `TxWrapper.WorkArea` state without context-local lookups.
`private static class`	`TxWrapper.WorkArea` Manages transaction-related state where buffers are involved.

Field Summary

Fields
Modifier and Type	Field and Description
`private boolean`	`autoRollback` Roll back the transaction when block finishes, if not previously acted upon
`private static ContextLocal<TxWrapper.WorkArea>`	`context` Stores context local instances of this class
`private Database`	`database` Backing database
`private DirtyShareContext`	`dirtyContext` Dirty share context
`private boolean`	`initialTx` `true` for an initial transaction only until the first commit or rollback
`private static CentralLogger`	`LOG` Logger
`private Persistence.Context`	`persistenceCtx` Persistence context, for access to database session and transaction
`private SavepointManager`	`savepointManager` Savepoint manager (can be `null`
`private TxWrapper.WorkArea`	`wa` The `TxWrapper.WorkArea` instance.

Constructor Summary

Constructors
Constructor and Description

TxWrapper(TxWrapper.WorkArea wa, Database database)
The sole constructor.

Constructors
Constructor and Description
`TxWrapper(TxWrapper.WorkArea wa, Database database)` The sole constructor.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`(package private) void`	`activate()` Activates the transaction.
`private void`	`begin()` Starts the actual transaction at persistence level.
`void`	`commit(boolean transaction)` Implementation of `Commitable` interface: saves any temporary state to the persistent form or storage that is associated with this class.
`void`	`deleted()` Implementation of `Finalizable` interface: provides a notification that the external program in which the object is registered is being deleted and the object's reference may be lost after this method is called.
`(package private) void`	`deregisterGlobalSavepointHooks()` Deregisters the finalizable for savepoint manager from the global block, if any.
`private void`	`end()` Shuts down the transaction at persistence level and performs key management.
`void`	`finished()` Implementation of `Finalizable` interface: Provides a notification that the scope in which the object is registered is ending and the object's reference may or may not be lost after this method is called.
`static TxWrapper.TxWrapperHelper`	`getHelper(BufferManager bm)` Get the helper to access the `Commitable` and `Resettable` state required to maintain transaction-related state where buffers are involved.
`(package private) boolean`	`isActive()` Checks whether this `TxWrapper` is active.
`void`	`iterate()` Implementation of `Finalizable` interface: provides a notification that the block whose scope in which the object is registered is about to iterate and attempt another pass.
`private java.lang.String`	`message(Persistence persistence, java.lang.String text)` Compose a message suitable for logging.
`(package private) void`	`registerSavepointHooks(boolean fullTx, int blockDepth)` Registers the commitable and finalizable for savepoint manager, if any.
`void`	`retry()` Implementation of `Finalizable` interface: provides a notification that the block whose scope in which the object is registered is about to retry the same iteration (all loop control data is unchanged).
`void`	`rollback(boolean transaction)` Implementation of `Commitable` interface: notifies that a rollback has just occurred (all state maintained through the `Undoable` interface has been already rolled back).
`java.lang.String`	`toString()` Convert the current object to its string representation to be used during debugging.
`void`	`validate(boolean transaction, boolean aggressiveFlush)` Implementation of `Commitable` interface: Notifies that a block is about to be normally exited or normally iterated and that any deferred validation processing should be executed.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface com.goldencode.p2j.util.Finalizable
entry, initFailure, weight

- Field Detail
  - LOG
```
private static final CentralLogger LOG
```
    Logger
  - context
```
private static final ContextLocal<TxWrapper.WorkArea> context
```
    Stores context local instances of this class
  - database
```
private final Database database
```
    Backing database
  - dirtyContext
```
private final DirtyShareContext dirtyContext
```
    Dirty share context
  - savepointManager
```
private final SavepointManager savepointManager
```
    Savepoint manager (can be null
  - persistenceCtx
```
private Persistence.Context persistenceCtx
```
    Persistence context, for access to database session and transaction
  - autoRollback
```
private boolean autoRollback
```
    Roll back the transaction when block finishes, if not previously acted upon
  - initialTx
```
private boolean initialTx
```
    true for an initial transaction only until the first commit or rollback
  - wa
```
private TxWrapper.WorkArea wa
```
    The TxWrapper.WorkArea instance.
- Constructor Detail
  - TxWrapper
```
TxWrapper(TxWrapper.WorkArea wa,
          Database database)
```
    The sole constructor.
    
    Parameters:
    
    wa - The TxWrapper.WorkArea instance.
    
    database - The Database where the transaction takes place.
- Method Detail
  - getHelper
```
public static TxWrapper.TxWrapperHelper getHelper(BufferManager bm)
```
    Get the helper to access the Commitable and Resettable state required to maintain transaction-related state where buffers are involved.
    
    Parameters:
    
    bm - The BufferManager instance.
    
    Returns:
    
    The TxWrapper.TxWrapperHelper instance.
  - iterate
```
public void iterate()
```
    Implementation of Finalizable interface: provides a notification that the block whose scope in which the object is registered is about to iterate and attempt another pass. This provides an opportunity to preserve state from the previous pass and make preparations for the coming pass.
    
    Specified by:
    
    iterate in interface Finalizable
  - retry
```
public void retry()
```
    Implementation of Finalizable interface: provides a notification that the block whose scope in which the object is registered is about to retry the same iteration (all loop control data is unchanged). This provides an opportunity to clear or reset state from the previous pass.
    
    Specified by:
    
    retry in interface Finalizable
  - finished
```
public void finished()
```
    Implementation of Finalizable interface: Provides a notification that the scope in which the object is registered is ending and the object's reference may or may not be lost after this method is called. This provides a natural and standard mechanism to clean-up any resources that may need to be closed explicitly such as operating system files or sockets.
    
    Specified by:
    
    finished in interface Finalizable
  - deleted
```
public void deleted()
```
    Implementation of Finalizable interface: provides a notification that the external program in which the object is registered is being deleted and the object's reference may be lost after this method is called.
    
    Specified by:
    
    deleted in interface Finalizable
  - commit
```
public void commit(boolean transaction)
```
    Implementation of Commitable interface: saves any temporary state to the persistent form or storage that is associated with this class.
    
    Specified by:
    
    commit in interface Commitable
    
    Parameters:
    
    transaction - true if this is a full transaction and false if this is only a sub-transaction (a nested scope with transaction support).
  - rollback
```
public void rollback(boolean transaction)
```
    Implementation of Commitable interface: notifies that a rollback has just occurred (all state maintained through the Undoable interface has been already rolled back). This notification can be used to implement cleanup of any custom state that needs to be maintained in this case. It can also be used to implement a rollback that is completely independent of the Undoable (externally driven) interface.
    
    Specified by:
    
    rollback in interface Commitable
    
    Parameters:
    
    transaction - true if this is a full transaction and false if this is only a sub-transaction (a nested scope with transaction support).
  - validate
```
public void validate(boolean transaction,
                     boolean aggressiveFlush)
```
    Implementation of Commitable interface: Notifies that a block is about to be normally exited or normally iterated and that any deferred validation processing should be executed.
    This particular implementation is a NOP.
    
    Specified by:
    
    validate in interface Commitable
    
    Parameters:
    
    transaction - Ignored.
    
    aggressiveFlush - Ignored.
  - registerSavepointHooks
```
void registerSavepointHooks(boolean fullTx,
                            int blockDepth)
```
    Registers the commitable and finalizable for savepoint manager, if any.
    
    Parameters:
    
    fullTx - true if this is a full-transaction.
    
    blockDepth - zero-based depth of target block, starting from the outermost block. 0 indicates the global block.
  - deregisterGlobalSavepointHooks
```
void deregisterGlobalSavepointHooks()
```
    Deregisters the finalizable for savepoint manager from the global block, if any.
  - activate
```
void activate()
```
    Activates the transaction. This entails starting a database-level transaction and activating a savepoint manager for that transaction.
  - isActive
```
boolean isActive()
```
    Checks whether this TxWrapper is active.
    
    Returns:
    
    true only if TxWrapper was activated.
  - toString
```
public java.lang.String toString()
```
    Convert the current object to its string representation to be used during debugging.
    
    Overrides:
    
    toString in class java.lang.Object
    
    Returns:
    
    A short string representation of this object to be used while debugging.
  - begin
```
private void begin()
```
    Starts the actual transaction at persistence level.
  - end
```
private void end()
```
    Shuts down the transaction at persistence level and performs key management.
  - message
```
private java.lang.String message(Persistence persistence,
                                 java.lang.String text)
```
    Compose a message suitable for logging. Reports open buffer scopes and context information in addition to a custom message.
    
    Parameters:
    
    persistence - Persistence object which will provide context info.
    
    text - Custom message text.
    
    Returns:
    
    Composed message text.

Class TxWrapper

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface com.goldencode.p2j.util.Finalizable

Field Detail

LOG

context

database

dirtyContext

savepointManager

persistenceCtx

autoRollback

initialTx

wa

Constructor Detail

TxWrapper

Method Detail

getHelper

iterate

retry

finished

deleted

commit

rollback

validate

registerSavepointHooks

deregisterGlobalSavepointHooks

activate

isActive

toString

begin

end

message