File	Doc	Category	Size	Date	Package
TransactionManager.java	API Doc	Azureus 3.0.3.4	6218	Sat Jun 02 14:13:56 BST 2007	com.aelitis.azureus.ui.swt.browser.txn

TransactionManager

• java.lang.Object

Fields Summary
private com.aelitis.azureus.core.messenger.ClientMessageContext	context
private Map	txnCtors
private Map	txns
private int	lastTxnId

Constructors Summary
public TransactionManager(com.aelitis.azureus.core.messenger.ClientMessageContext context) this.context = context;

Methods Summary
public synchronized Transaction	cancelTransaction(java.lang.String type) Cancels the current transaction if there is one for this listener and the browser in the given message. param type used to determine the transaction to return return the current transaction or null if none exists Transaction txn = getTransaction(type); if ( txn != null ) { txn.cancel(); } return txn;
protected Transaction	createTransaction(java.lang.String type) Creates a new transaction for this listener and the browser in the given message. If no transaction class was specified in the constructor, subclasses must override this method. param message holds a reference to the browser return a new transaction Constructor ctor = (Constructor) txnCtors.get(type); if ( ctor == null ) { throw new IllegalStateException("Unregistered transaction type: " + type); } try { Object[] params = new Object[] { new Integer(getNextTransactionId()), type, context }; return (Transaction) ctor.newInstance(params); } catch ( Exception e ) { throw new RuntimeException("Exception creating transaction for type " + type, e); }
private int	getNextTransactionId() Increments the last transaction ID and returns the new value. return a unique ID to use for a new transaction return ++lastTxnId;
public synchronized Transaction	getTransaction(java.lang.String type) Returns the current transaction of the given type. param type used to locate the transaction return the transaction or null if none exists return (Transaction) txns.get(type);
public void	registerTransactionType(java.lang.String type, java.lang.Class clazz) Registers the given transaction subclass as that to be created for the given type identifier. param clazz used when creating transactions throws IllegalArgumentException if txnClass is null or not a subclass of {@link Transaction} throws IllegalArgumentException if the appropriate constructor of txnClass cannot be found or accessed if ( clazz == null ) { throw new IllegalArgumentException("Transaction class must be non-null"); } if ( ! Transaction.class.isAssignableFrom(clazz) ) { throw new IllegalArgumentException("Transaction class " + clazz.getName() + " must be a subclass of Transaction"); } try { Class[] ctorParams = new Class[] { Integer.TYPE, String.class, ClientMessageContext.class }; Constructor ctor = clazz.getConstructor(ctorParams); txnCtors.put(type, ctor); } catch ( Exception e ) { throw new IllegalArgumentException( "Cannot access appropriate constructor for " + clazz.getName()); }
synchronized boolean	removeTransaction(Transaction txn) Removes the given transaction from current status if it's current. param txn the Transaction to be removed return true if the transaction was current; false otherwise if ( txn != getTransaction(txn.getType()) ) { return false; } return txns.remove(txn.getType()) == txn;
public synchronized Transaction	startTransaction(java.lang.String type) Starts a new transaction of the given type after canceling the current transaction if any. param type used to determine the transaction class to create return a new started transaction cancelTransaction(type); Transaction txn = createTransaction(type); if ( txn != null ) { if ( ! txn.start() ) { return null; } txns.put(type, txn); } return txn;