org.nuiton.web.filter
Class TopiaTransactionFilter

java.lang.Object
  org.nuiton.web.filter.TopiaTransactionFilter

All Implemented Interfaces:

javax.servlet.Filter

public abstract class TopiaTransactionFilter
extends Object
implements javax.servlet.Filter

Purpose of this filter

This filter purpose is to inject in the request a transaction from TopiaContext and deal with the complete lifecycle of a topia transaction while a request.

The injected transaction will be closed (if was really opened) at the end of the request.

Configuration of the filter

The filter accepts two configuration parameters:

• excludeMethods: This parameters configure a set of method names which should never be called on the proxied transaction. When a such method is called on the transaction then the filter will pass in the hook onExcludeMethod(Object, Method, Object[]).

  Default implementation of this hook is to throw an exception.

• unusedMethods: This parameters configure a set of method names which should be by-pass when the proxied transaction was not still open (via a TopiaContext.beginTransaction(). When a such method is called on the transaction then the filter will pass in the hook onUnusedMethod(Object, Method, Object[]).

  Default implementation of this hook is to not return null values.

Obtain the transaction

The (proxied) transaction is pushed as an attribute in the servlet request.

The attribute name is TOPIA_TRANSACTION_REQUEST_ATTRIBUTE.

A convience method is created here to obtain the transaction getTransaction(ServletRequest) :

 TopiaContext tx = TopiaTransactionFilter.getTransaction(ServletRequest);
 

If you prefer to not use this nice method, you can also do this:

 TopiaContext tx = (TopiaContext) request.getAttribute(TopiaTransactionFilter#TOPIA_TRANSACTION_REQUEST_ATTRIBUTE);
 

Since:

1.6

Author:

tchemit

Nested Class Summary

class

TopiaTransactionFilter.TopiaTransactionProxyInvocationHandler Handler of a proxy on a TopiaContext.

Field Summary

static String[]	DEFAULT_EXCLUDE_METHODS
static String[]	DEFAULT_UNUSED_METHODS
protected Set<String>	excludeMethods names of methods to forbid access while using proxy.
static String	TOPIA_TRANSACTION_REQUEST_ATTRIBUTE
protected Set<String>	unusedMethods names of methods to by-pass if no transaction opened on proxy.

Constructor Summary

TopiaTransactionFilter()

Method Summary

protected abstract org.nuiton.topia.TopiaContext	beginTransaction() Method to open a new transaction.
void	destroy()
void	doFilter(javax.servlet.ServletRequest request, javax.servlet.ServletResponse response, javax.servlet.FilterChain chain)
Set<String>	getExcludeMethods()
static org.nuiton.topia.TopiaContext	getTransaction(javax.servlet.ServletRequest request)
Set<String>	getUnusedMethods()
void	init(javax.servlet.FilterConfig filterConfig)
protected Object	onExcludeMethod(Object proxy, Method method, Object[] args) Hook method called when a method with his name in excludeMethods was invoked on the proxied transaction.
protected Object	onUnusedMethod(Object proxy, Method method, Object[] args) Hook method called when a method with his name in unusedMethods was invoked on the proxied transaction while the underlying transaction is still not opened.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

TOPIA_TRANSACTION_REQUEST_ATTRIBUTE

public static final String TOPIA_TRANSACTION_REQUEST_ATTRIBUTE

See Also:

Constant Field Values

DEFAULT_EXCLUDE_METHODS

public static final String[] DEFAULT_EXCLUDE_METHODS

DEFAULT_UNUSED_METHODS

public static final String[] DEFAULT_UNUSED_METHODS

excludeMethods

protected Set<String> excludeMethods

names of methods to forbid access while using proxy.

unusedMethods

protected Set<String> unusedMethods

names of methods to by-pass if no transaction opened on proxy.

Constructor Detail

TopiaTransactionFilter

public TopiaTransactionFilter()

Method Detail

getExcludeMethods

public Set<String> getExcludeMethods()

getUnusedMethods

public Set<String> getUnusedMethods()

getTransaction

public static org.nuiton.topia.TopiaContext getTransaction(javax.servlet.ServletRequest request)

beginTransaction

protected abstract org.nuiton.topia.TopiaContext beginTransaction()
                                                           throws org.nuiton.topia.TopiaRuntimeException

Method to open a new transaction.

Returns:

the new freshly opened transaction

Throws:

org.nuiton.topia.TopiaRuntimeException - if any problem while opening a new transaction

destroy

public void destroy()

Specified by:

destroy in interface javax.servlet.Filter

init

public void init(javax.servlet.FilterConfig filterConfig)
          throws javax.servlet.ServletException

Specified by:

init in interface javax.servlet.Filter

Throws:

javax.servlet.ServletException

doFilter

public void doFilter(javax.servlet.ServletRequest request,
                     javax.servlet.ServletResponse response,
                     javax.servlet.FilterChain chain)
              throws IOException,
                     javax.servlet.ServletException

Specified by:

doFilter in interface javax.servlet.Filter

Throws:

IOException

javax.servlet.ServletException

onExcludeMethod

protected Object onExcludeMethod(Object proxy,
                                 Method method,
                                 Object[] args)
                          throws Throwable

Hook method called when a method with his name in excludeMethods was invoked on the proxied transaction.

Parameters:

proxy - proxied transaction

method - method invoked

args - arguments of the invoked method

Returns:

the return code of the method

Throws:

Throwable - if any error to do.

onUnusedMethod

protected Object onUnusedMethod(Object proxy,
                                Method method,
                                Object[] args)
                         throws Throwable

Hook method called when a method with his name in unusedMethods was invoked on the proxied transaction while the underlying transaction is still not opened.

Parameters:

proxy - the proxy itself

method - method invoked

args - arguments of the invoked method

Returns:

the return code of the method

Throws:

Throwable - if any error to do.