File	Doc	Category	Size	Date	Package
AbstractTransactionalListener.java	API Doc	Azureus 3.0.3.4	7498	Mon Dec 04 11:59:36 GMT 2006	com.aelitis.azureus.ui.swt.browser.txn

AbstractTransactionalListener

• java.lang.Object
  • com.aelitis.azureus.ui.swt.browser.msg.AbstractMessageListener

Fields Summary
public static final String	TXN_REQUIRED Start a new transaction or use an existing one (like J2EE REQUIRED)
public static final String	TXN_REQUIRES_NEW Start a new transaction, aborting any existing one (like J2EE REQUIRES_NEW)
public static final String	TXN_MANDATORY Require an existing transaction, erroring if there isn't one (like J2EE MANDATORY)
public static final String	TXN_NONE Handle without a transaction, ignoring any existing one (like J2EE NOT_SUPPORTED)
private String	txnType
private Map	txnStatesByOp

Constructors Summary
public AbstractTransactionalListener(String id) Uses the listener's ID as the transaction type. param id uniquely identifies this listener to the dispatcher and defines the transaction type this(id, id);
public AbstractTransactionalListener(String id, String txnType) Provides a transaction type different from the listener's ID. param id uniquely identifies this listener to the dispatcher param txnType used to access transactions via the context super(id); this.txnType = txnType;

Methods Summary
protected Transaction	cancelTransaction() Cancels the current transaction if there is one for this listener. return the cancelled transaction or null if none exists return context.cancelTransaction(txnType);
protected java.lang.String	getOperationTxnState(java.lang.String operationId) Returns the transaction state (attribute) param operationId return return (String) txnStatesByOp.get(operationId);
protected Transaction	getTransaction() Returns the current transaction for this listener. return the current transaction or null if none exists return context.getTransaction(txnType);
public java.lang.String	getTransactionType() Returns the transaction type used by this listener. return the transaction type used by this listener return txnType;
public void	handleMessage(com.aelitis.azureus.ui.swt.browser.msg.BrowserMessage message) Ensures the correct transaction state before handling the message. param message contains the operation ID used to lookup the transaction state String state = getOperationTxnState(message.getOperationId()); if ( state == null ) { context.debug("Ignoring message without transactional state: " + message); return; } Transaction txn = getTransaction(); if ( state.equals(TXN_REQUIRED) ) { // start new if none exists if ( txn == null ) { txn = startTransaction(); } } else if ( state.equals(TXN_REQUIRES_NEW) ) { // cancel current and start new cancelTransaction(); txn = startTransaction(); } else if ( state.equals(TXN_MANDATORY) ) { // use existing or error if ( txn == null ) { transactionStateViolated(message, state, null); return; } } else if ( state.equals(TXN_NONE) ) { // ignore existing if ( txn != null ) { txn = null; } } else { context.debug("Ignoring message with invalid transactional state (" + state + "): " + message); return; } if ( txn != null ) { handleTxnlMessage(message, txn); } else { handleNonTxnlMessage(message); }
protected void	handleNonTxnlMessage(com.aelitis.azureus.ui.swt.browser.msg.BrowserMessage message) Handle a browser message that doesn't require a transaction. Subclasses must override if they have any non-transactional operations. param message the mesage to be handled
protected abstract void	handleTxnlMessage(com.aelitis.azureus.ui.swt.browser.msg.BrowserMessage message, Transaction txn) Handle a browser message that require a transaction. Subclasses must implement this method, otherwise they should extend {@link AbstractMessageListener}. param message the mesage to be handled param txn the current transaction
private void	registerOperation(java.lang.String operationId, java.lang.String txnState) txnStatesByOp.put(operationId, txnState);
protected void	registerOperationTxnMandatory(java.lang.String operationId) registerOperation(operationId, TXN_MANDATORY);
protected void	registerOperationTxnNone(java.lang.String operationId) registerOperation(operationId, TXN_NONE);
protected void	registerOperationTxnRequired(java.lang.String operationId) registerOperation(operationId, TXN_REQUIRED);
protected void	registerOperationTxnRequiresNew(java.lang.String operationId) registerOperation(operationId, TXN_REQUIRES_NEW);
protected Transaction	startTransaction() Starts a new transaction for this listener. return a new started transaction return context.startTransaction(txnType);
protected void	transactionStateViolated(com.aelitis.azureus.ui.swt.browser.msg.BrowserMessage message, java.lang.String state, Transaction txn) Called when the necessary transactional state is not correct for the given message. Override to handle the error more gracefully. param message the message being handled param state the state required by the message param txn the existing transaction or null if none throw new IllegalStateException("Transaction state violated - state: " + state + ", txn: " + txn);