com.tangosol.net
Class AbstractPriorityTask

java.lang.Object
  com.tangosol.util.Base
      com.tangosol.util.BitHelper
          com.tangosol.util.ExternalizableHelper
              com.tangosol.net.AbstractPriorityTask

All Implemented Interfaces:

ExternalizableLite, PortableObject, PriorityTask, Serializable

Direct Known Subclasses:

PriorityAggregator, PriorityFilter, PriorityProcessor

public abstract class AbstractPriorityTask
extends ExternalizableHelper
implements PriorityTask, ExternalizableLite, PortableObject

An abstract base for PriorityTask implementations. It implements all PriorityTask interface methods and is intended to be extended for concrete uses.

Since:

Coherence 3.3

Author:

gg 2007.03.20

Field Summary

Fields inherited from interface com.tangosol.net.PriorityTask

SCHEDULE_FIRST, SCHEDULE_IMMEDIATE, SCHEDULE_STANDARD, TIMEOUT_DEFAULT, TIMEOUT_NONE

Constructor Summary

AbstractPriorityTask()

Method Summary

long	getExecutionTimeoutMillis() Obtain the maximum amount of time this task is allowed to run before the corresponding service will attempt to stop it.
long	getRequestTimeoutMillis() Obtain the maximum amount of time a calling thread is willing to wait for a result of the request execution.
int	getSchedulingPriority() Obtain this task's scheduling priority.
void	readExternal(DataInput in) Restore the contents of this object by loading the object's state from the passed DataInput object.
void	readExternal(PofReader in) Restore the contents of a user type instance by reading its state using the specified PofReader object.
void	runCanceled(boolean fAbandoned) This method will be called if and only if all attempts to interrupt this task were unsuccesful in stopping the execution or if the execution was canceled before it had a chance to run at all.
void	setExecutionTimeoutMillis(long lTimeout) Specify the maximum amount of time this task is allowed to run before the corresponding service will attempt to stop it.
void	setRequestTimeoutMillis(long lTimeout) Specify the maximum amount of time a calling thread is willing to wait for a result of the request execution.
void	setSchedulingPriority(int iPriority) Specify this task's scheduling priority.
void	writeExternal(DataOutput out) Save the contents of this object by storing the object's state into the passed DataOutput object.
void	writeExternal(PofWriter out) Save the contents of a POF user type instance by writing its state using the specified PofWriter object.

Methods inherited from class com.tangosol.util.BitHelper

countBits, countBits, countBits, indexOfLSB, indexOfLSB, indexOfLSB, indexOfMSB, indexOfMSB, indexOfMSB, toBitString, toBitString, toBitString

Constructor Detail

AbstractPriorityTask

public AbstractPriorityTask()

Method Detail

getSchedulingPriority

public int getSchedulingPriority()

Obtain this task's scheduling priority. Valid values are one of the SCHEDULE_* constants.

Specified by:

getSchedulingPriority in interface PriorityTask

Returns:

this task's scheduling priority

getExecutionTimeoutMillis

public long getExecutionTimeoutMillis()

Obtain the maximum amount of time this task is allowed to run before the corresponding service will attempt to stop it.

The value of TIMEOUT_DEFAULT indicates a default timeout value configured for the corresponding service; the value of TIMEOUT_NONE indicates that this task can execute indefinitely.

If, by the time the specified amount of time passed, the task has not finished, the service will attempt to stop the execution by using the Thread.interrupt() method. In the case that interrupting the thread does not result in the task's termination, the PriorityTask.runCanceled(boolean) method will be called.

Specified by:

getExecutionTimeoutMillis in interface PriorityTask

Returns:

the execution timeout value in millisecods or one of the special TIMEOUT_* values

getRequestTimeoutMillis

public long getRequestTimeoutMillis()

Obtain the maximum amount of time a calling thread is willing to wait for a result of the request execution. The request time is measured on the client side as the time elapsed from the moment a request is sent for execution to the corresponding server node(s) and includes:

• the time it takes to deliver the request to the executing node(s);
• the interval between the time the task is received and placed into a service queue until the execution starts;
• the task execution time;
• the time it takes to deliver a result back to the client.

The value of TIMEOUT_DEFAULT indicates a default timeout value configured for the corresponding service; the value of TIMEOUT_NONE indicates that the client thread is willing to wait indefinitely until the task execution completes or is canceled by the service due to a task execution timeout specified by the PriorityTask.getExecutionTimeoutMillis() value.

If the specified amount of time elapsed and the client has not received any response from the server, an RequestTimeoutException will be thrown to the caller.

Specified by:

getRequestTimeoutMillis in interface PriorityTask

Returns:

the request timeout value in milliseconds or one of the special TIMEOUT_* values

runCanceled

public void runCanceled(boolean fAbandoned)

This method will be called if and only if all attempts to interrupt this task were unsuccesful in stopping the execution or if the execution was canceled before it had a chance to run at all.

Since this method is usually called on a service thread, implementors must exercise extreme caution since any delay introduced by the implementation will cause a delay of the corresponding service.

This implementation is a no-op.

Specified by:

runCanceled in interface PriorityTask

Parameters:

fAbandoned - true if the task has timed-out, but all attempts to interrupt it were unsuccesful in stopping the execution; otherwise the task was never started

setSchedulingPriority

public void setSchedulingPriority(int iPriority)

Specify this task's scheduling priority. Valid values are one of the SCHEDULE_* constants.

Parameters:

iPriority - this task's scheduling priority

setExecutionTimeoutMillis

public void setExecutionTimeoutMillis(long lTimeout)

Specify the maximum amount of time this task is allowed to run before the corresponding service will attempt to stop it.

Parameters:

lTimeout - the task timeout value in milliseconds

setRequestTimeoutMillis

public void setRequestTimeoutMillis(long lTimeout)

Specify the maximum amount of time a calling thread is willing to wait for a result of the request execution.

Parameters:

lTimeout - the request timeout value in milliseconds

readExternal

public void readExternal(DataInput in)
                  throws IOException

Restore the contents of this object by loading the object's state from the passed DataInput object.

Specified by:

readExternal in interface ExternalizableLite

Parameters:

in - the DataInput stream to read data from in order to restore the state of this object

Throws:

IOException - if an I/O exception occurs

NotActiveException - if the object is not in its initial state, and therefore cannot be deserialized into

writeExternal

public void writeExternal(DataOutput out)
                   throws IOException

Save the contents of this object by storing the object's state into the passed DataOutput object.

Specified by:

writeExternal in interface ExternalizableLite

Parameters:

out - the DataOutput stream to write the state of this object to

Throws:

IOException - if an I/O exception occurs

readExternal

public void readExternal(PofReader in)
                  throws IOException

Restore the contents of a user type instance by reading its state using the specified PofReader object.

The AbstractPriorityTask implementation reserves property indexes 0 - 9.

Specified by:

readExternal in interface PortableObject

Parameters:

in - the PofReader from which to read the object's state

Throws:

IOException - if an I/O error occurs

writeExternal

public void writeExternal(PofWriter out)
                   throws IOException

Save the contents of a POF user type instance by writing its state using the specified PofWriter object.

The AbstractPriorityTask implementation reserves property indexes 0 - 9.

Specified by:

writeExternal in interface PortableObject

Parameters:

out - the PofWriter to which to write the object's state

Throws:

IOException - if an I/O error occurs