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

Class QueryBinding

java.lang.Object

com.inductiveautomation.perspective.gateway.binding.AbstractPollingBinding

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

All Implemented Interfaces:

QueryBindingConstants, Binding

public class QueryBinding
extends AbstractPollingBinding
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, 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 QualifiedValue	execute()	Perform the blocking execution of this polling binding.
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.
protected void	preExecutionPrep()	This method will be called before AbstractPollingBinding.execute() is called to give implementations the opportunity to prepare any data before execution begins.
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

Method Detail

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

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

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

preExecutionPrep

protected void preExecutionPrep()

Description copied from class: AbstractPollingBinding

This method will be called before AbstractPollingBinding.execute() is called to give implementations the opportunity to prepare any data before execution begins. This method will be called within a synchronized block holding this lock.

Overrides:

preExecutionPrep in class AbstractPollingBinding

execute

protected QualifiedValue execute()
                          throws java.lang.Exception

Description copied from class: AbstractPollingBinding

Perform the blocking execution of this polling binding. This should always execute on the _executor service_

Specified by:

execute in class AbstractPollingBinding

Returns:

The resulting QualifiedValue from the binding execution

Throws:

java.lang.Exception - If there is a problem executing the binding

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