Package org.apache.commons.jcs3.auxiliary.remote

Class RemoteCacheNoWait<K,V>

java.lang.Object
org.apache.commons.jcs3.auxiliary.AbstractAuxiliaryCache<K,V>
org.apache.commons.jcs3.auxiliary.remote.RemoteCacheNoWait<K,V>
All Implemented Interfaces:
AuxiliaryCache<K,V>, ICache<K,V>, ICacheType
public class RemoteCacheNoWait<K,V> extends AbstractAuxiliaryCache<K,V>
The RemoteCacheNoWait wraps the RemoteCacheClient. The client holds a handle on the RemoteCacheService.

Used to queue up update requests to the underlying cache. These requests will be processed in their order of arrival via the cache event queue processor.

Typically errors will be handled down stream. We only need to kill the queue if an error makes it to this level from the queue. That can only happen if the queue is damaged, since the events are Processed asynchronously.

There is no reason to create a queue on startup if the remote is not healthy.

If the remote cache encounters an error it will zombie--create a balking facade for the service. The Zombie will queue up items until the connection is restored. An alternative way to accomplish the same thing would be to stop, not destroy the queue at this level. That way items would be added to the queue and then when the connection is restored, we could start the worker threads again. This is a better long term solution, but it requires some significant changes to the complicated worker queues.

  • Constructor Details

    • RemoteCacheNoWait

      public RemoteCacheNoWait(IRemoteCacheClient<K,V> cache)
      Constructs with the given remote cache, and fires up an event queue for asynchronous processing.

      Parameters:
      cache -

  • Method Details

    • update

      public void update(ICacheElement<K,V> element) throws IOException
      Adds a put event to the queue.

      Parameters:
      element -
      Throws:
      IOException

    • get

      public ICacheElement<K,V> get(K key) throws IOException
      Synchronously reads from the remote cache.

      Specified by:
      get in interface ICache<K,V>
      Specified by:
      get in class AbstractAuxiliaryCache<K,V>
      Parameters:
      key -
      Returns:
      element from the remote cache, or null if not present
      Throws:
      IOException

    • getMatching

      public Map<K,ICacheElement<K,V>> getMatching(String pattern) throws IOException
      Description copied from interface: ICache
      Gets items from the cache matching the given pattern. Items from memory will replace those from remote sources. This only works with string keys. It's too expensive to do a toString on every key. Auxiliaries will do their best to handle simple expressions. For instance, the JDBC disk cache will convert * to % and . to _
      Parameters:
      pattern -
      Returns:
      Map
      Throws:
      IOException

    • getMultiple

      public Map<K,ICacheElement<K,V>> getMultiple(Set<K> keys) throws IOException
      Gets multiple items from the cache based on the given set of keys. Sends the getMultiple request on to the server rather than looping through the requested keys.

      Parameters:
      keys -
      Returns:
      a map of K key to ICacheElement<K, V> element, or an empty map if there is no data in cache for any of these keys
      Throws:
      IOException

    • getKeySet

      public Set<K> getKeySet() throws IOException
      Return the keys in this cache.

      Returns:
      a set of the key type TODO This should probably be done in chunks with a range passed in. This will be a problem if someone puts a 1,000,000 or so items in a region.
      Throws:
      IOException - if access to the auxiliary cache fails
      See Also:

    • remove

      public boolean remove(K key) throws IOException
      Adds a remove request to the remote cache.

      Parameters:
      key -
      Returns:
      if this was successful
      Throws:
      IOException

    • removeAll

      public void removeAll() throws IOException
      Adds a removeAll request to the remote cache.

      Throws:
      IOException

    • dispose

      public void dispose()
      Adds a dispose request to the remote cache.

    • getSize

      public int getSize()
      No remote invocation.

      Returns:
      The size value

    • getCacheType

      public ICacheType.CacheType getCacheType()
      No remote invocation.

      Returns:
      The cacheType value

    • getStatus

      public CacheStatus getStatus()
      Returns the async cache status. An error status indicates either the remote connection is not available, or the asyn queue has been unexpectedly destroyed. No remote invocation.

      Returns:
      The status value

    • getCacheName

      public String getCacheName()
      Gets the cacheName attribute of the RemoteCacheNoWait object

      Returns:
      The cacheName value

    • fixCache

      public void fixCache(ICacheServiceNonLocal<?,?> remote)
      Replaces the remote cache service handle with the given handle and reset the event queue by starting up a new instance.

      Parameters:
      remote -

    • resetEventQ

      public void resetEventQ()
      Resets the event q by first destroying the existing one and starting up new one.

      There may be no good reason to kill the existing queue. We will sometimes need to set a new listener id, so we should create a new queue. We should let the old queue drain. If we were Connected to the failover, it would be best to finish sending items.

    • getRemoteCache

      protected IRemoteCacheClient<K,V> getRemoteCache()
      This is temporary. It allows the manager to get the lister.

      Returns:
      the instance of the remote cache client used by this object

    • getAuxiliaryCacheAttributes

      public AuxiliaryCacheAttributes getAuxiliaryCacheAttributes()
      Description copied from interface: AuxiliaryCache
      This returns the generic attributes for an auxiliary cache. Most implementations will cast this to a more specific type.

      Returns:
      Returns the AuxiliaryCacheAttributes.

    • getCacheEventQueue

      protected ICacheEventQueue<K,V> getCacheEventQueue()
      This is for testing only. It allows you to take a look at the event queue.

      Returns:
      ICacheEventQueue

    • toString

      public String toString()
      Returns the stats and the cache.toString().

      Overrides:
      toString in class Object
      See Also:

    • getStats

      public String getStats()
      Returns the statistics in String form.

      Returns:
      String

    • getStatistics

      public IStats getStatistics()
      Returns:
      statistics about this communication

    • getEventLoggingExtraInfo

      public String getEventLoggingExtraInfo()
      this won't be called since we don't do ICache logging here.

      Specified by:
      getEventLoggingExtraInfo in class AbstractAuxiliaryCache<K,V>
      Returns:
      String