com.dxfeed.ipf.live

Class InstrumentProfileCollector

java.lang.Object

com.dxfeed.ipf.live.InstrumentProfileCollector

public class InstrumentProfileCollector
extends Object

Collects instrument profile updates and provides the live list of instrument profiles. This class contains a map that keeps a unique instrument profile per symbol. This class is intended to be used with InstrumentProfileConnection as a repository that keeps profiles of all known instruments. See InstrumentProfileConnection for a usage example.

As set of instrument profiles stored in this collector can be accessed with view method. A snapshot plus a live stream of updates can be accessed with addUpdateListener method.

Removal of instrument profile is represented by an InstrumentProfile instance with a type equal to InstrumentProfileType.REMOVED.name().

This class is thread-safe.

Constructor Summary

Constructors

Constructor and Description
InstrumentProfileCollector()

Method Summary

Modifier and Type	Method and Description
void	addUpdateListener(InstrumentProfileUpdateListener listener) Adds listener that is notified about any updates in the set of instrument profiles.
protected InstrumentProfile	copyInstrumentProfile(InstrumentProfile ip) A hook to create a defensive copy of the instrument profile that is saved into this collector.
protected static Executor	createAgentExecutor()
Executor	getExecutor() Returns executor for processing instrument profile update notifications.
long	getLastUpdateTime() Returns last modification time (in milliseconds) of instrument profiles or zero if it is unknown.
void	removeGenerations(Set<Object> generations) Removes instrument profiles with non-null generation tags from a given set.
void	removeUpdateListener(InstrumentProfileUpdateListener listener) Removes listener that is notified about any updates in the set of instrument profiles.
void	setExecutor(Executor executor) Changes executor for processing instrument profile update notifications.
void	updateInstrumentProfile(InstrumentProfile ip) Convenience method to update one instrument profile in this collector.
void	updateInstrumentProfiles(List<InstrumentProfile> ips, Object generation) Updates a list of instrument profile and assign them a generation tag.
Iterable<InstrumentProfile>	view() Returns a concurrent view of the set of instrument profiles.

Methods inherited from class java.lang.Object

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

Constructor Detail

InstrumentProfileCollector

public InstrumentProfileCollector()

Method Detail

getLastUpdateTime

public final long getLastUpdateTime()

Returns last modification time (in milliseconds) of instrument profiles or zero if it is unknown. Note, that while the time is represented in milliseconds, the actual granularity of time here is a second.

Returns:

last modification time (in milliseconds) of instrument profiles or zero if it is unknown.

updateInstrumentProfile

public final void updateInstrumentProfile(InstrumentProfile ip)

Convenience method to update one instrument profile in this collector. This is a shortcut for:

    updateInstrumentProfiles(Collections.singletonList(ip), null);
 

Note, that this method stores reference to an instance of a given InstrumentProfile object inside this collector, unless a protected method copyInstrumentProfile is overridden to create a copy.

Parameters:

ip - instrument profile.

updateInstrumentProfiles

public final void updateInstrumentProfiles(List<InstrumentProfile> ips,
                                           Object generation)

Updates a list of instrument profile and assign them a generation tag. A generation tag can be later use with removeGenerations method.

Removal of instrument profile is represented by an InstrumentProfile instance with a type equal to InstrumentProfileType.REMOVED.name().

Note, that this method stores references to instances of InstrumentProfile objects from a given list inside this collector, unless a protected method copyInstrumentProfile is overridden to create a copy.

Parameters:

ips - a list of instrument profiles.

generation - a generation tag, may be null.

removeGenerations

public final void removeGenerations(Set<Object> generations)

Removes instrument profiles with non-null generation tags from a given set. Note, that this method takes O(N) time, where N is the number of stored instrument profiles in this collector. It shall be used sparingly.

Parameters:

generations - a set of generation tags.

view

public final Iterable<InstrumentProfile> view()

Returns a concurrent view of the set of instrument profiles. Note, that removal of instrument profile is represented by an InstrumentProfile instance with a type equal to InstrumentProfileType.REMOVED.name(). Normally, this view exposes only non-removed profiles. However, if iteration is concurrent with removal, then a removed instrument profile (with a removed type) can be exposed by this view.

Returns:

a concurrent view of the set of instrument profiles.

getExecutor

public Executor getExecutor()

Returns executor for processing instrument profile update notifications. By default, single-threaded executor is used to process updates asynchronously.

Returns:

executor for processing instrument profile update notifications.

setExecutor

public void setExecutor(Executor executor)

Changes executor for processing instrument profile update notifications.

Parameters:

executor - non-null executor for processing instrument profile update notifications.

addUpdateListener

public final void addUpdateListener(InstrumentProfileUpdateListener listener)

Adds listener that is notified about any updates in the set of instrument profiles. If a set of instrument profiles is not empty, then this listener will be immediately notified.

Parameters:

listener - profile update listener.

removeUpdateListener

public final void removeUpdateListener(InstrumentProfileUpdateListener listener)

Removes listener that is notified about any updates in the set of instrument profiles.

Parameters:

listener - profile update listener.

copyInstrumentProfile

protected InstrumentProfile copyInstrumentProfile(InstrumentProfile ip)

A hook to create a defensive copy of the instrument profile that is saved into this collector. This method is invoked from inside of updateInstrumentProfile and updateInstrumentProfiles methods when a decision is made to save an instrument profile into this data structure.

This implementation returns the original instrument reference. Overriding methods may choose to create and return a copy of the instrument profile object instead.

Override this method to safely reuse InstrumentProfile instances that are passed into this collector. This lazily creates their defensive copies, just when the corresponding instrument profile is detected to have been changed.

Parameters:

ip - the original instrument profile.

Returns:

the original or copied instrument profile.

createAgentExecutor

protected static Executor createAgentExecutor()