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com.tangosol.net
Class RefreshableAddressProvider

java.lang.Object
com.tangosol.util.Base
com.tangosol.net.RefreshableAddressProvider

All Implemented Interfaces:

AddressProvider, SocketAddressProvider

public abstract class RefreshableAddressProvider

extends Base

implements AddressProvider

A RefreshableAddressProvider is an abstract AddressProvider implementation that maintains a nearly up-to-date cache of Addresses that is periodically asynchronously refreshed. This ensures that the behaviour of this AddressProvider will be performant (specifically non-blocking).

Implementing subclasses should provide implementation logic for deciding how and when the address cache should be refreshed. That logic must reside in getNextAddressInternal() instead of getNextAddress().

Note: subclasses must call initialize() before the AddressProvider is used.

Since:

Coherence 3.5

Author:

rhl 2008-12-14

Nested Class Summary

protected class

RefreshableAddressProvider.RefreshThread

Field Summary

protected Daemon	m_daemonRefresh The refresh daemon.
protected java.util.Iterator	m_iterator The iterator used to implement the AddressProvider interface.
protected java.util.List	m_listCache The cached addresses.
static long	REFRESH_DEFAULT Default refresh time of 10 seconds.

Constructor Summary

RefreshableAddressProvider()
Default constructor.

RefreshableAddressProvider(long lRefresh)
Construct a RefreshableAddressProvider with the specified refresh interval.

Method Summary

void	accept() This method should be called by the client immediately after it determines that it can successfully use an address returned by the SocketAddressProvider.getNextAddress() method.
protected java.util.Iterator	ensureIterator() Return the cache iterator.
boolean	equals(java.lang.Object o) SocketAddressProvider instances are considered equivalent iff they consistently produce the same resulting set of addresses.
protected void	finalize() Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
java.net.InetSocketAddress	getNextAddress() Covariant of SocketAddressProvider.getNextAddress() which returns an InetSocketAddress.
protected abstract java.net.InetSocketAddress	getNextAddressInternal() Obtain the next available address to use.
int	hashCode() Return the hash code for this SocketAddressProvider.
protected void	initialize() Initialize the RefreshableAddressProvider and prepare it for use by populating the address-list cache and starting the refresh thread.
protected void	instantiateRefreshThread(long lRefresh) Start the refresh thread.
protected abstract boolean	isExpired() Check if the cached address list should be refreshed.
protected void	refreshAddressList() Refresh the cached address list using the underlying provider.
void	reject(java.lang.Throwable eCause) This method should be called by the client immediately after it determines that an attempt to use an address returned by the SocketAddressProvider.getNextAddress() method has failed.

Field Detail

REFRESH_DEFAULT

public static final long REFRESH_DEFAULT

Default refresh time of 10 seconds.

See Also:

Constant Field Values

m_listCache

protected volatile java.util.List m_listCache

The cached addresses.

m_iterator

protected java.util.Iterator m_iterator

The iterator used to implement the AddressProvider interface.

m_daemonRefresh

protected Daemon m_daemonRefresh

The refresh daemon.

Constructor Detail

RefreshableAddressProvider

public RefreshableAddressProvider()

Default constructor.

RefreshableAddressProvider

public RefreshableAddressProvider(long lRefresh)

Construct a RefreshableAddressProvider with the specified refresh interval.

Parameters:

lRefresh - the refresh interval

Method Detail

initialize

protected void initialize()

Initialize the RefreshableAddressProvider and prepare it for use by populating the address-list cache and starting the refresh thread.

getNextAddressInternal

protected abstract java.net.InetSocketAddress getNextAddressInternal()

Obtain the next available address to use.

Returns:

the next available address or null if the list of available addresses was exhausted

isExpired

protected abstract boolean isExpired()

Check if the cached address list should be refreshed. This method may be called frequently.

Returns:

true iff the cached address list should be refreshed

equals

public boolean equals(java.lang.Object o)

SocketAddressProvider instances are considered equivalent iff they consistently produce the same resulting set of addresses.

Note: the general contract of hashCode and equals() should be preserved; AddressProviders that are "equal" should produce the same hashCode.

Specified by:

equals in interface SocketAddressProvider

Parameters:

o - the Object to compare this SocketAddressProvider to for equality

Returns:

true iff this SocketAddressProvider is equal to the specified object

hashCode

public int hashCode()

Return the hash code for this SocketAddressProvider.

Specified by:

hashCode in interface SocketAddressProvider

Returns:

the hash code for this SocketAddressProvider

finalize

protected void finalize()

Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.

getNextAddress

public final java.net.InetSocketAddress getNextAddress()

Covariant of SocketAddressProvider.getNextAddress() which returns an InetSocketAddress.

Specified by:

getNextAddress in interface AddressProvider

Specified by:

getNextAddress in interface SocketAddressProvider

Returns:

the next available address or null if the list of available addresses was exhausted

accept

public final void accept()

This method should be called by the client immediately after it determines that it can successfully use an address returned by the SocketAddressProvider.getNextAddress() method.

Specified by:

accept in interface SocketAddressProvider

reject

public final void reject(java.lang.Throwable eCause)

This method should be called by the client immediately after it determines that an attempt to use an address returned by the SocketAddressProvider.getNextAddress() method has failed.

Specified by:

reject in interface SocketAddressProvider

Parameters:

eCause - (optional) an exception that carries the reason why the the caller rejected the previously returned address

refreshAddressList

protected void refreshAddressList()

Refresh the cached address list using the underlying provider.

instantiateRefreshThread

protected void instantiateRefreshThread(long lRefresh)

Start the refresh thread.

ensureIterator

protected java.util.Iterator ensureIterator()

Return the cache iterator.

Returns:

the cache iterator

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