Package com.illumon.iris.db.util

Class PrintListener

java.lang.Object

com.illumon.util.referencecounting.ReferenceCounted

com.illumon.iris.db.util.liveness.LivenessArtifact

com.illumon.iris.db.v2.InstrumentedListenerBase

com.illumon.iris.db.v2.InstrumentedShiftAwareListener

com.illumon.iris.db.util.PrintListener

All Implemented Interfaces:

com.fishlib.base.log.LogOutputAppendable, NotificationQueue.Dependency, LivenessManager, LivenessNode, LivenessReferent, ListenerBase, ShiftAwareListener, Serializable

@ScriptApi
public class PrintListener
extends InstrumentedShiftAwareListener

A simple listener that prints out each update received from a table.

This can be used to debug the performance of a query by attaching to various tables in an effort to understand the update pattern. Optionally, you can also print out the head of the table.

Output is directed to stdout, thus this should not be enabled in production queries.

After you are finished, call the stop() method to remove this listener from the source table.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class com.illumon.iris.db.v2.InstrumentedShiftAwareListener

InstrumentedShiftAwareListener.Notification

Nested classes/interfaces inherited from class com.illumon.iris.db.v2.InstrumentedListenerBase

InstrumentedListenerBase.ErrorNotification, InstrumentedListenerBase.NotificationBase

Nested classes/interfaces inherited from interface com.illumon.iris.db.v2.ShiftAwareListener

ShiftAwareListener.Update

Constructor Summary

Constructors

Constructor	Description
PrintListener(String description, DynamicTable table)	Create a PrintListener attached to the given table.
PrintListener(String description, DynamicTable table, int rowCount)	Create a PrintListener attached to the given table.

Method Summary

Modifier and Type	Method	Description
protected void	destroy()	Attempt to release (destructively when necessary) resources held by this object.
void	dropReference()	Drop a previously-retained reference to this referent.
WeakReference<? extends LivenessReferent>	getWeakReference()	Get a WeakReference to this referent.
void	initializeTransientFieldsForLiveness()	Package-private for Serializable sub-classes to use in readObject only.
void	onFailureInternal(Throwable originalException, UpdatePerformanceTracker.Entry sourceEntry)
protected void	onReferenceCountAtZero()	Callback method that will be invoked when the reference count returns to zero.
void	onUpdate(ShiftAwareListener.Update upstream)	Process notification of table changes.
void	stop()	Remove this listener from the table.
boolean	tryManage(LivenessReferent referent)	Attempt to add the specified referent to this manager.
boolean	tryRetainReference()	If this referent is "live", behave as LivenessReferent.retainReference() and return true.

Methods inherited from class com.illumon.iris.db.v2.InstrumentedShiftAwareListener

getNotification

Methods inherited from class com.illumon.iris.db.v2.InstrumentedListenerBase

append, canExecute, getEntry, getErrorNotification, onFailure, onFailureInternalWithDependent, satisfied, setVerboseLogging, toString

Methods inherited from class com.illumon.iris.db.util.liveness.LivenessArtifact

manageWithCurrentScope, unmanage, unmanage

Methods inherited from class com.illumon.util.referencecounting.ReferenceCounted

decrementReferenceCount, incrementReferenceCount, resetReferenceCount, tryDecrementReferenceCount, tryIncrementReferenceCount

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.illumon.iris.db.v2.ListenerBase

getErrorNotification, onFailure

Methods inherited from interface com.illumon.iris.db.util.liveness.LivenessManager

manage, tryManage

Methods inherited from interface com.illumon.iris.db.util.liveness.LivenessReferent

dropReference, getReferentDescription, getWeakReference, retainReference, tryRetainReference

Constructor Details

PrintListener

@ScriptApi public PrintListener(String description, DynamicTable table)

Create a PrintListener attached to the given table. Note that this automatically listens to the source table.

Parameters:

description - the description (for use in each print statement)

table - the table to attach to

PrintListener

@ScriptApi public PrintListener(String description, DynamicTable table, int rowCount)

Create a PrintListener attached to the given table. Note that this automatically listens to the source table.

Parameters:

description - the description (for use in each print statement)

table - the table to attach to

rowCount - how many rows to print out on each update

Method Details

onUpdate

public void onUpdate(ShiftAwareListener.Update upstream)

Description copied from interface: ShiftAwareListener

Process notification of table changes.

Parameters:

upstream - The set of upstream table updates.

onFailureInternal

public void onFailureInternal(Throwable originalException, UpdatePerformanceTracker.Entry sourceEntry)

Specified by:

onFailureInternal in class InstrumentedListenerBase

stop

public void stop()

Remove this listener from the table.

initializeTransientFieldsForLiveness

@VisibleForTesting public final void initializeTransientFieldsForLiveness()

Package-private for Serializable sub-classes to use in readObject only. Public to allow unit tests in another package to work around mock issues where the constructor is never invoked.

tryRetainReference

public final boolean tryRetainReference()

Description copied from interface: LivenessReferent

If this referent is "live", behave as LivenessReferent.retainReference() and return true. Otherwise, returns false rather than throwing an exception.

Specified by:

tryRetainReference in interface LivenessReferent

Returns:

True if this referent was retained, false otherwise

dropReference

public final void dropReference()

Description copied from interface: LivenessReferent

Drop a previously-retained reference to this referent.

Specified by:

dropReference in interface LivenessReferent

getWeakReference

public WeakReference<? extends LivenessReferent> getWeakReference()

Description copied from interface: LivenessReferent

Get a WeakReference to this referent. This may be cached, or newly created.

Specified by:

getWeakReference in interface LivenessReferent

Returns:

A new or cached reference to this referent

tryManage

public final boolean tryManage(@NotNull LivenessReferent referent)

Description copied from interface: LivenessManager

Attempt to add the specified referent to this manager.

Specified by:

tryManage in interface LivenessManager

Parameters:

referent - The referent to add

Returns:

Whether the referent was in fact added

destroy

protected void destroy()

Attempt to release (destructively when necessary) resources held by this object. This may render the object unusable for subsequent operations. Implementations should be sure to call super.destroy().

This is intended to only ever be used as a side effect of decreasing the reference count to 0.

onReferenceCountAtZero

protected final void onReferenceCountAtZero()

Description copied from class: ReferenceCounted

Callback method that will be invoked when the reference count returns to zero.

Specified by:

onReferenceCountAtZero in class ReferenceCounted