protected static class SimpleOverflowMap.Status extends Object
Modifier and Type | Field and Description |
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protected static int |
STATE_MASK_FRONT
Bitmask for entry in front.
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protected static int |
STATE_MASK_INSYNC
Bitmask for value in front and back being in sync.
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protected static int |
STATE_MASK_RETAIN
Bitmask for fields that would indicate that the Status must not be discarded.
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protected static int |
STATE_MASK_STATUS
Bitmask for status (least significant three bits reserved).
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protected static int |
STATE_VALUE_RETAIN
Bit values for fields that would indicate that the Status can be discarded.
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protected static int |
STATUS_AVAILABLE
Status: The Status object exists and no thread is currently performing processing against the associated entry.
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protected static int |
STATUS_COMMITTING
Status: The Status object represents an Entry that was very recently being processed, and is currently finalizing the results of that processing.
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protected static int |
STATUS_INVALIDATED
Status: The Status object has been discarded.
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protected static int |
STATUS_PROCESSING
Status: The Status object represents an Entry that is currently being processed.
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protected static int |
STATUS_RESERVED
Status: The Status object has been reserved for processing by a thread but is not yet processing.
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Constructor and Description |
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Status()
Construct a Status object for a specific key.
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Modifier and Type | Method and Description |
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MapEvent |
closeProcessing()
Finish the processing of the entry for which this Status exists and proceed to the commit phase.
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protected boolean |
commitAndMaybeInvalidate()
Finish the commit for the entry for which this Status exists.
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protected boolean |
extractFlag(int nMask)
Extract a particular masked flag from the state of the Status object.
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protected int |
extractState(int nMask)
Extract a particular masked value from the state of the Status object.
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String |
getDescription()
Assemble a human-readable description.
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protected MapEvent |
getFrontEvent()
For internal use only, return the current event from the front Map.
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Thread |
getOwnerThread()
Determine the thread that owns the Status object, if the Status object is processing or committing.
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protected int |
getState()
Determine the state of the Status object.
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protected int |
getStatus()
Determine the enumerated status of the Status object.
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boolean |
hasEvent()
Determine if an event has occurred against the Entry for which this Status exists.
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boolean |
isAvailable()
Determine if the Status object is available.
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boolean |
isBackUpToDate()
Determine if the entry for which this Status exists has the same value in the front Map as in the back Map.
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boolean |
isCommitting()
Determine if the Status object represents an Entry that has been processed and the results of that processing are being committed.
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protected boolean |
isDiscardable()
Determine if this Status object can be discarded.
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boolean |
isEntryInFront()
Determine if the entry for which this Status exists is present in the front map.
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boolean |
isOwnedByCurrentThread()
Determine if the current thread owns this Status object.
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boolean |
isProcessing()
Determine if the Status object represents an Entry that is currently being processed.
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boolean |
isReserved()
Determine if the Status object is reserved.
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boolean |
isValid()
Determine if the Status object is valid.
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protected MapEvent |
mergeEvents(MapEvent evtOld, MapEvent evtNew)
Merge two events that have been raised in sequence from a given map.
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boolean |
registerFrontEvent(MapEvent evt)
Register a MapEvent that has been raised by the front Map against the same key for which this Status object exists.
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protected boolean |
requestReservation()
Attempt to reserve the Status by marking it as committing if it is available.
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void |
setBackUpToDate(boolean fUpToDate)
Specify that the value stored in the back Map is known to be up to date (not needing to be written to the back if evicted from the front).
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void |
setEntryInFront(boolean fEntryInFront)
Specify whether the entry for which this Status exists is present in the front map.
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protected void |
setFrontEvent(MapEvent evt)
For internal use only, store the current event from the front Map.
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protected void |
setOwnerThread(Thread thread)
Specify the thread that owns the Status object.
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protected void |
setState(int nState)
Specify the state of the Status object.
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protected void |
setStatus(int nStatus)
Determine the enumerated state of the Status object.
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MapEvent |
takeEvent()
Obtain the most recent front Map event that has occurred against the Entry for which this Status exists.
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String |
toString()
Returns a string representation of the object.
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protected void |
updateFlag(int nMask, boolean f)
Update a particular masked flag within the state of the Status object.
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protected void |
updateState(int nMask, int nValue)
Update a particular masked value within the state of the Status object.
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protected MapEvent |
useReservation()
After having successfully made a reservation, this method completes the reservation process by setting the status to processing for the thread that made the reservation.
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protected MapEvent |
waitForAvailable()
Wait for the Entry that this Status represents to become available.
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protected void |
waitForReservationDecision()
Wait for the Entry that this Status represents to no longer be reserved.
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protected static final int STATE_MASK_STATUS
protected static final int STATE_MASK_FRONT
protected static final int STATE_MASK_INSYNC
protected static final int STATUS_AVAILABLE
protected static final int STATUS_RESERVED
protected static final int STATUS_PROCESSING
protected static final int STATUS_COMMITTING
protected static final int STATUS_INVALIDATED
protected static final int STATE_MASK_RETAIN
protected static final int STATE_VALUE_RETAIN
protected int getStatus()
protected void setStatus(int nStatus)
nStatus
- a number corresponding to one of the enumeration represented by the STATUS_* constantspublic boolean isValid()
public boolean isAvailable()
public boolean isReserved()
public boolean isProcessing()
public boolean isCommitting()
public Thread getOwnerThread()
protected void setOwnerThread(Thread thread)
thread
- the owning thread, or nullpublic boolean isOwnedByCurrentThread()
public boolean isEntryInFront()
public void setEntryInFront(boolean fEntryInFront)
fEntryInFront
- pass true if the entry is stored in the front map, false if notpublic boolean isBackUpToDate()
public void setBackUpToDate(boolean fUpToDate)
protected MapEvent getFrontEvent()
protected void setFrontEvent(MapEvent evt)
evt
- the cummulative front Map event for the Entry represented by this Status object, or null to clear the eventpublic boolean hasEvent()
public MapEvent takeEvent()
protected boolean isDiscardable()
This is an internal method.
public String getDescription()
public String toString()
protected MapEvent waitForAvailable()
This is an internal method. It requires the caller to have synchronized on the Status object before calling this method.
protected boolean requestReservation()
useReservation()
or commitAndMaybeInvalidate()
(to cancel the reservation).
This is an internal method.
protected void waitForReservationDecision()
This is an internal method. It requires the caller to have synchronized on the Status object before calling this method.
protected MapEvent useReservation()
This is an internal method.
public MapEvent closeProcessing()
protected boolean commitAndMaybeInvalidate()
This is an internal method. It requires the caller to have first synchronized on the registry (Map) that contains the Status objects and then to have synchronized on this Status object itself, in that explicit order. Failure to follow this rule will result in deadlock and/or exceptional conditions.
public boolean registerFrontEvent(MapEvent evt)
For truly predictable behavior, this requires that the front Map implementation be synchronized during the raising of events, such that an event will only be raised from the front Map on one thread at a time. The event listener (for the overflow map) must then synchronize on this Status object (to verify that it is indeed valid before registering the event) and the register the event while holding that synchronization. If the registration returns a deferred indicator, then the
evt
- the event that has occurred against an entry in the front Map with the same key which this Status object representsprotected MapEvent mergeEvents(MapEvent evtOld, MapEvent evtNew)
evtOld
- the first eventevtNew
- the second eventprotected int getState()
protected void setState(int nState)
nState
- the new bit-packed state for the Status objectprotected int extractState(int nMask)
nMask
- the mask identifying the valueprotected void updateState(int nMask, int nValue)
nMask
- the mask of bits to store the value withinnValue
- the value to store inside that maskprotected boolean extractFlag(int nMask)
nMask
- the mask identifying the flagprotected void updateFlag(int nMask, boolean f)
nMask
- the mask of flag bit to store the flag withinf
- the boolean value to store within that mask