org.gridgain.grid.kernal

Class GridJobContextImpl

java.lang.Object

org.gridgain.grid.util.lang.GridMetadataAwareAdapter

org.gridgain.grid.kernal.GridJobContextImpl

All Implemented Interfaces:

Externalizable, Serializable, GridComputeJobContext, GridComputeJobContinuation, GridMetadataAware

public class GridJobContextImpl
extends GridMetadataAwareAdapter
implements GridComputeJobContext, Externalizable

Remote job context implementation.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
GridJobContextImpl() Empty constructor required by Externalizable.
GridJobContextImpl(GridKernalContext ctx, GridUuid jobId)
GridJobContextImpl(GridKernalContext ctx, GridUuid jobId, Map<? extends Serializable,? extends Serializable> attrs)

Method Summary

Methods

Modifier and Type	Method and Description
<T> T	affinityKey() Gets affinity key with which job was co-located.
String	cacheName() Gets cache name for which job was co-located.
void	callcc() Resumes job if it was held by GridComputeJobContinuation.holdcc() method.
<K,V> V	getAttribute(K key) Gets attribute from this job context.
Map<Object,Object>	getAttributes() Gets all attributes present in this job context.
GridUuid	getJobId() Gets ID of the job this context belongs to.
boolean	heldcc() Checks if job execution has been temporarily held (suspended).
<T> T	holdcc() Holds (suspends) a given job indefinitely until GridComputeJobContinuation.callcc() is called.
<T> T	holdcc(long timeout) Holds (suspends) a given job for specified timeout or until GridComputeJobContinuation.callcc() is called.
void	job(GridJobWorker job)
void	readExternal(ObjectInput in)
void	setAttribute(Object key, Object val) Sets an attribute into this job context.
void	setAttributes(Map<?,?> attrs) Sets map of attributes into this job context.
String	toString()
void	writeExternal(ObjectOutput out)

Methods inherited from class org.gridgain.grid.util.lang.GridMetadataAwareAdapter

addMeta, addMetaIfAbsent, addMetaIfAbsent, allMeta, clone, copyMeta, copyMeta, hasMeta, hasMeta, meta, putMetaIfAbsent, putMetaIfAbsent, readExternalMeta, removeMeta, removeMeta, replaceMeta, writeExternalMeta

Methods inherited from class java.lang.Object

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

Constructor Detail

GridJobContextImpl

public GridJobContextImpl()

Empty constructor required by Externalizable.

GridJobContextImpl

public GridJobContextImpl(@Nullable
                  GridKernalContext ctx,
                  GridUuid jobId)

Parameters:

ctx - Kernal context.

jobId - Job ID.

GridJobContextImpl

public GridJobContextImpl(GridKernalContext ctx,
                  GridUuid jobId,
                  Map<? extends Serializable,? extends Serializable> attrs)

Parameters:

ctx - Kernal context.

jobId - Job ID.

attrs - Job attributes.

Method Detail

job

public void job(GridJobWorker job)

Parameters:

job - Job worker.

getJobId

public GridUuid getJobId()

Gets ID of the job this context belongs to.

Specified by:

getJobId in interface GridComputeJobContext

Returns:

ID of the job this context belongs to.

setAttribute

public void setAttribute(Object key,
                @Nullable
                Object val)

Sets an attribute into this job context.

Specified by:

setAttribute in interface GridComputeJobContext

Parameters:

key - Attribute key.

val - Attribute value.

setAttributes

public void setAttributes(Map<?,?> attrs)

Sets map of attributes into this job context.

Specified by:

setAttributes in interface GridComputeJobContext

Parameters:

attrs - Local attributes.

getAttribute

public <K,V> V getAttribute(K key)

Gets attribute from this job context.

Specified by:

getAttribute in interface GridComputeJobContext

Type Parameters:

K - Type of the attribute key.

V - Type of the attribute value.

Parameters:

key - Attribute key.

Returns:

Attribute value (possibly null).

getAttributes

public Map<Object,Object> getAttributes()

Gets all attributes present in this job context.

Specified by:

getAttributes in interface GridComputeJobContext

Returns:

All attributes.

heldcc

public boolean heldcc()

Checks if job execution has been temporarily held (suspended).

If job has completed its execution, then false is always returned.

Specified by:

heldcc in interface GridComputeJobContinuation

Returns:

True if job has been held.

holdcc

public <T> T holdcc()

Holds (suspends) a given job indefinitely until GridComputeJobContinuation.callcc() is called. Job will remain in active queue, but its GridComputeJobContinuation.heldcc() method will return true. Implementations of GridCollisionSpi should check if jobs are held or not as needed.

All jobs should stop their execution and return right after calling 'holdcc(..)' method. For convenience, this method always returns null, so you can hold and return in one line by calling 'return holdcc()' method.

If job is not running or has completed its execution, then no-op.

The 'cc' suffix stands for 'current-continuation' which is a pretty standard notation for this concept that originated from Scheme programming language. Basically, the job is held to be continued later, hence the name of the method.

Specified by:

holdcc in interface GridComputeJobContinuation

Returns:

Always returns null for convenience to be used in code with return statement.

holdcc

public <T> T holdcc(long timeout)

Holds (suspends) a given job for specified timeout or until GridComputeJobContinuation.callcc() is called. Holds (suspends) a given job for specified timeout or until GridComputeJobContinuation.callcc() is called. Job will remain in active queue, but its GridComputeJobContinuation.heldcc() method will return true. Implementations of GridCollisionSpi should check if jobs are held or not as needed.

All jobs should stop their execution and return right after calling 'holdcc(..)' method. For convenience, this method always returns null, so you can hold and return in one line by calling 'return holdcc()'.

If job is not running or has completed its execution, then no-op.

The 'cc' suffix stands for 'current-continuation' which is a fairly standard notation for this concept. Basically, the job is held to be continued later, hence the name of the method.

Specified by:

holdcc in interface GridComputeJobContinuation

Parameters:

timeout - Timeout in milliseconds after which job will be automatically resumed.

Returns:

Always returns null for convenience to be used in code with return statement.

callcc

public void callcc()

Resumes job if it was held by GridComputeJobContinuation.holdcc() method. Resuming job means that GridComputeJob.execute() method will be called again. It is user's responsibility to check, as needed, whether job is executing from scratch and has been resumed.

Note that the job is resumed with exactly the same state as of when it was 'held' via the GridComputeJobContinuation.holdcc() method.

If job is not running, has not been suspended, or has completed its execution, then no-op.

The method is named after 'call-with-current-continuation' design pattern, commonly abbreviated as 'call/cc', which originated in Scheme programming language.

Specified by:

callcc in interface GridComputeJobContinuation

cacheName

public String cacheName()

Gets cache name for which job was co-located.

Specified by:

cacheName in interface GridComputeJobContext

Returns:

Cache name if job was co-located or null otherwise.

See Also:

GridComputeJobContext.affinityKey(), GridCompute.affinityCall(String, Object, Callable), GridCompute.affinityRun(String, Object, Runnable)

affinityKey

public <T> T affinityKey()

Gets affinity key with which job was co-located.

Specified by:

affinityKey in interface GridComputeJobContext

Returns:

Affinity key if job was co-located or null otherwise.

See Also:

GridComputeJobContext.cacheName(), GridCompute.affinityCall(String, Object, Callable), GridCompute.affinityRun(String, Object, Runnable)

writeExternal

public void writeExternal(ObjectOutput out)
                   throws IOException

Specified by:

writeExternal in interface Externalizable

Throws:

IOException

readExternal

public void readExternal(ObjectInput in)
                  throws IOException,
                         ClassNotFoundException

Specified by:

readExternal in interface Externalizable

Throws:

IOException

ClassNotFoundException

toString

public String toString()

Overrides:

toString in class Object