Package com.inductiveautomation.perspective.gateway.binding.query

Class QueryBinding

java.lang.Object

com.inductiveautomation.perspective.gateway.binding.AbstractPollingBinding<QueryBindingParams>

com.inductiveautomation.perspective.gateway.binding.query.QueryBinding

All Implemented Interfaces:

QueryBindingConstants, Binding

public class QueryBinding
extends AbstractPollingBinding<QueryBindingParams>
implements QueryBindingConstants

Implementation of a perspective query binding. These bindings will execute a named query, optionally on a rate.

The polling rate, as well as the parameter values, are all expressions that can produce new values at any time. Care is taken to ensure that any blocking work takes place on the perspective working thread-pool.

Nested Class Summary

Nested classes/interfaces inherited from class com.inductiveautomation.perspective.gateway.binding.AbstractPollingBinding

AbstractPollingBinding.State

Field Summary

Fields inherited from class com.inductiveautomation.perspective.gateway.binding.AbstractPollingBinding

context, state

Fields inherited from interface com.inductiveautomation.perspective.gateway.api.Binding

BAD_CONFIG, BAD_REF, BIDIRECTIONAL_KEY, COALESCE_KEY, INITIAL_VALUE, MDC_BINDING_TARGET, NOT_FOUND

Fields inherited from interface com.inductiveautomation.perspective.common.config.constants.QueryBindingConstants

QUERY_PATH, TYPE_ID

Method Summary

Modifier and Type	Method	Description
protected QueryBindingParams	buildFetchParameters()	This method will be called when it is time to fetch a new value.
static QualifiedValue	execute(QueryBindingParams params)
protected boolean	isDirty()	If any dependencies of the implementation have changed, this method should return true, which will kick off another execution if dependencies have changed while the execution was running.
protected boolean	isReady()	Indicates whether or not the instance of the underlying implementation is ready for execution.
Collection<PropertyReference>	resolveReferences()
void	shutdown()	Shut down the binding.
void	startup()	Start up the binding.

Methods inherited from class com.inductiveautomation.perspective.gateway.binding.AbstractPollingBinding

onUserRefresh, scheduleNow

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.inductiveautomation.perspective.gateway.api.Binding

isBidirectional, onTargetUpdated, shouldCoalesce

Method Details

resolveReferences

public Collection<PropertyReference> resolveReferences()

Specified by:

resolveReferences in interface Binding

Overrides:

resolveReferences in class AbstractPollingBinding<QueryBindingParams>

startup

public void startup()

Description copied from interface: Binding

Start up the binding. Will be called on-queue

Specified by:

startup in interface Binding

Overrides:

startup in class AbstractPollingBinding<QueryBindingParams>

shutdown

public void shutdown()

Description copied from interface: Binding

Shut down the binding. Will be called on-queue

Specified by:

shutdown in interface Binding

Overrides:

shutdown in class AbstractPollingBinding<QueryBindingParams>

isReady

protected boolean isReady()

Description copied from class: AbstractPollingBinding

Indicates whether or not the instance of the underlying implementation is ready for execution.

Specified by:

isReady in class AbstractPollingBinding<QueryBindingParams>

isDirty

protected boolean isDirty()

Description copied from class: AbstractPollingBinding

If any dependencies of the implementation have changed, this method should return true, which will kick off another execution if dependencies have changed while the execution was running.

Specified by:

isDirty in class AbstractPollingBinding<QueryBindingParams>

buildFetchParameters

protected QueryBindingParams buildFetchParameters()

Description copied from class: AbstractPollingBinding

This method will be called when it is time to fetch a new value. The parameter object must implement hashcode and equals, and must contain everything needed to run this parameter's fetch function. The parameter object will be given to the ValueCache, which will then execute the fetch function if a new value is needed. This method will be called within a synchronized block holding this lock.

Specified by:

buildFetchParameters in class AbstractPollingBinding<QueryBindingParams>

execute

public static QualifiedValue execute(QueryBindingParams params)