org.semispace
Class SemiSpace

java.lang.Object
  org.semispace.SemiSpace

All Implemented Interfaces:

SemiSpaceInterface

public class SemiSpace
extends Object
implements SemiSpaceInterface

A tuple space implementation which can be distributed with terracotta. This is the main class from which the SemiSpace interface is obtained.

Nested Class Summary

protected class

SemiSpace.WrappedInternalWriter Need to wrap write in own thread in order to make terracotta pick it up.

Field Summary

static long

ONE_DAY

Method Summary

protected boolean	cancelElement(Long id, boolean isTake, String className)
protected boolean	cancelListener(ListenerHolder holder)
Long[]	findAllHolderIds()
String	findOrWaitLeaseForTemplate(Map<String,String> templateSet, long timeout, boolean isToTakeTheLease) Public for the benefit of the webservices interface.
SemiSpaceAdminInterface	getAdmin() Return admin element
protected SemiSpaceStatistics	getStatistics() For the benefit of junit test(s) - defensively copied statistics
com.thoughtworks.xstream.XStream	getXStream() Exposing xstream instance in order to allow outside manipulation of aliases and classloader affiliation.
void	harvest() Harvest old elements from diverse listeners.
SemiEventRegistration	notify(Map<String,String> searchProps, SemiEventListener listener, long duration) Basically the same as the notify method demanded by the interface, except that it accepts search properties directly.
SemiEventRegistration	notify(Object tmpl, SemiEventListener listener, long duration) None of the parameters can be null
protected void	notifyListeners(DistributedEvent distributedEvent) Distributed notification method.
int	numberOfBlockingRead() Need present statistics here due to spring JMX configuration.
int	numberOfBlockingTake() Need present statistics here due to spring JMX configuration.
int	numberOfMissedRead() Need present statistics here due to spring JMX configuration.
int	numberOfMissedTake() Need present statistics here due to spring JMX configuration.
int	numberOfNumberOfListeners() Need present statistics here due to spring JMX configuration.
int	numberOfRead() Need present statistics here due to spring JMX configuration.
int	numberOfSpaceElements() Return the number of elements in the space.
int	numberOfTake() Need present statistics here due to spring JMX configuration.
int	numberOfWrite() Need present statistics here due to spring JMX configuration.
Object	processTemplate(Object template) Create a pre-processed template object that can be used to reduce the amount of work required to match templates during a take.
<T> T	read(T tmpl, long timeout) Read an object from the space, which has matching fields (or getters) with the template
Holder	readHolderById(long hId) Used for retrieving element with basis in id
<T> T	readIfExists(T tmpl) Same as read, with duration 0
protected boolean	renewElement(Holder holder, long duration)
protected boolean	renewListener(ListenerHolder holder, long duration)
protected Map<String,String>	retrievePropertiesFromObject(Object examine) Protected for the benefit of junit test(s)
static SemiSpaceInterface	retrieveSpace()
void	setAdmin(SemiSpaceAdminInterface admin) Preparing for future injection of admin.
<T> T	take(T tmpl, long timeout) Same as read, except that the object is removed from the space.
<T> T	takeIfExists(T tmpl) Same as take, with a duration of 0
SemiLease	write(Object entry, long leaseTimeMs) Notice that the lease time is the time in milliseconds the element is wants to live, not the system time plus the time to live.
SemiLease	writeToElements(String entryClassName, long leaseTimeMs, String xml, Map<String,String> searchMap) This method is public for the benefit of the web services, which shortcuts the writing process.

Methods inherited from class java.lang.Object

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

Field Detail

ONE_DAY

public static final long ONE_DAY

See Also:

Constant Field Values

Method Detail

retrieveSpace

public static SemiSpaceInterface retrieveSpace()

Returns:

Return the space

notify

public SemiEventRegistration notify(Object tmpl,
                                    SemiEventListener listener,
                                    long duration)

None of the parameters can be null

Specified by:

notify in interface SemiSpaceInterface

Parameters:

tmpl - Template to be matched.

listener - Listener to be notified when object with a matching template is found

duration - How long this particular listener is valid.

Returns:

Returning null if something went wrong or was wrong, a registration object otherwise.

See Also:

SemiSpaceInterface.notify(Object, SemiEventListener, long)

notify

public SemiEventRegistration notify(Map<String,String> searchProps,
                                    SemiEventListener listener,
                                    long duration)

Basically the same as the notify method demanded by the interface, except that it accepts search properties directly. Used from the web services class. None of the parameters can be null

Returns:

Returning null if something went wrong or was wrong, a registration object otherwise.

notifyListeners

protected void notifyListeners(DistributedEvent distributedEvent)

Distributed notification method.

write

public SemiLease write(Object entry,
                       long leaseTimeMs)

Notice that the lease time is the time in milliseconds the element is wants to live, not the system time plus the time to live.

Specified by:

write in interface SemiSpaceInterface

Parameters:

entry - Object to be written into the space

leaseTimeMs - Life time in milliseconds of the written object

Returns:

Either the resulting lease or null if an error

writeToElements

public SemiLease writeToElements(String entryClassName,
                                 long leaseTimeMs,
                                 String xml,
                                 Map<String,String> searchMap)

This method is public for the benefit of the web services, which shortcuts the writing process. All values are expected to be non-null and valid upon entry.

read

public <T> T read(T tmpl,
                  long timeout)

Description copied from interface: SemiSpaceInterface

Read an object from the space, which has matching fields (or getters) with the template

Specified by:

read in interface SemiSpaceInterface

Parameters:

tmpl - Object of exactly the same type as what is wanted as return value, with zero or more none-null fields or getters.

timeout - How long you are willing to wait for an answer / match.

Returns:

An object when matches the template, or null of none are found.

findOrWaitLeaseForTemplate

public String findOrWaitLeaseForTemplate(Map<String,String> templateSet,
                                         long timeout,
                                         boolean isToTakeTheLease)

Public for the benefit of the webservices interface.

Parameters:

timeout - how long to wait in milliseconds. If timeout is zero or negative, query once.

isToTakeTheLease - true if the element shall be marked as taken.

Returns:

XML version of data, if found, or null

readIfExists

public <T> T readIfExists(T tmpl)

Description copied from interface: SemiSpaceInterface

Same as read, with duration 0

Specified by:

readIfExists in interface SemiSpaceInterface

See Also:

SemiSpaceInterface.read(Object, long)

readHolderById

public Holder readHolderById(long hId)

Used for retrieving element with basis in id

Returns:

Element with given holder id, or null if not found (or expired

take

public <T> T take(T tmpl,
                  long timeout)

Description copied from interface: SemiSpaceInterface

Same as read, except that the object is removed from the space.

Specified by:

take in interface SemiSpaceInterface

See Also:

SemiSpaceInterface.read(Object, long)

takeIfExists

public <T> T takeIfExists(T tmpl)

Description copied from interface: SemiSpaceInterface

Same as take, with a duration of 0

Specified by:

takeIfExists in interface SemiSpaceInterface

See Also:

SemiSpaceInterface.take(Object, long), SemiSpaceInterface.read(Object, long)

processTemplate

public Object processTemplate(Object template)

Create a pre-processed template object that can be used to reduce the amount of work required to match templates during a take. Applications that take a lot of objects using the same template instance, a noticeable performance improvement can be had.

Parameters:

template - The object to preprocess

Returns:

A pre-processed object that can be passed to read/take

retrievePropertiesFromObject

protected Map<String,String> retrievePropertiesFromObject(Object examine)

Protected for the benefit of junit test(s)

Parameters:

examine - Non-null object

setAdmin

public void setAdmin(SemiSpaceAdminInterface admin)

Preparing for future injection of admin. Note that you must call initialization yourself after setting the object

This is tested in junit test (and under terracotta).

getAdmin

public SemiSpaceAdminInterface getAdmin()

Return admin element

harvest

public void harvest()

Harvest old elements from diverse listeners. Used from the periodic harvester and junit tests.

numberOfSpaceElements

public int numberOfSpaceElements()

Return the number of elements in the space. Notice that this may report old elements that have not been purged yet.

numberOfBlockingRead

public int numberOfBlockingRead()

Need present statistics here due to spring JMX configuration.

numberOfBlockingTake

public int numberOfBlockingTake()

Need present statistics here due to spring JMX configuration.

numberOfMissedRead

public int numberOfMissedRead()

Need present statistics here due to spring JMX configuration.

numberOfMissedTake

public int numberOfMissedTake()

Need present statistics here due to spring JMX configuration.

numberOfNumberOfListeners

public int numberOfNumberOfListeners()

Need present statistics here due to spring JMX configuration.

numberOfRead

public int numberOfRead()

Need present statistics here due to spring JMX configuration.

numberOfTake

public int numberOfTake()

Need present statistics here due to spring JMX configuration.

numberOfWrite

public int numberOfWrite()

Need present statistics here due to spring JMX configuration.

getStatistics

protected SemiSpaceStatistics getStatistics()

For the benefit of junit test(s) - defensively copied statistics

cancelListener

protected boolean cancelListener(ListenerHolder holder)

renewListener

protected boolean renewListener(ListenerHolder holder,
                                long duration)

cancelElement

protected boolean cancelElement(Long id,
                                boolean isTake,
                                String className)

Parameters:

isTake - true if reason for the cancellation is a take.

renewElement

protected boolean renewElement(Holder holder,
                               long duration)

Returns:

true if the object actually was renewed. (I.e. it exists and got a new timeout.)

findAllHolderIds

public Long[] findAllHolderIds()

See Also:

HolderContainer.findAllHolderIds()

getXStream

public com.thoughtworks.xstream.XStream getXStream()

Exposing xstream instance in order to allow outside manipulation of aliases and classloader affiliation.

Returns:

The xstream instance used.