Class ContinuousQuery

Class to hold Object query and values, intended for notifications.

Inheritance
System.Object
ContinuousQuery
Assembly: Alachisoft.NCache.Client.dll
Syntax
public class ContinuousQuery

Constructors

ContinuousQuery(QueryCommand)

Initializes a new instance of the ContinuousQuery class.

Declaration
public ContinuousQuery(QueryCommand command)
Parameters
Type Name Description
QueryCommand command

QueryCommand containing query text and values.

Properties

Command

Property to set Query Command for ContinuousQuery.

Declaration
public QueryCommand Command { get; set; }
Property Value
Type Description
QueryCommand

It holds query text and values.

Methods

Equals(Object)

Compares two instances of ContinuousQuery for equality.

Declaration
public override bool Equals(object obj)
Parameters
Type Name Description
System.Object obj

An instance of ContinuousQuery.
Returns
Type Description
System.Boolean

True, if both ContinuousQuery instances are the same. Otherwise false.

Overrides
System.Object.Equals(System.Object)

GetHashCode()

Computes the hash code for the current object.

Declaration
public override int GetHashCode()
Returns
Type Description
System.Int32

Hash code for the current object.

Overrides
System.Object.GetHashCode()

RegisterClearNotification(ContinuousQueryClearCallback)

This method registers a custom callback that is fired if dataset of a Continuous Query is cleared.

Declaration
public void RegisterClearNotification(ContinuousQueryClearCallback callback)
Parameters
Type Name Description
ContinuousQueryClearCallback callback

A delegate to register your custom method with
Examples

The following example shows how to register the notification callback. First, create an CacheClearedCallback.

 public static void CacheCleared()
  {
    ...
  }

Then, declare your Continuous Query.

ContinuousQuery cQ=new ContinuousQuery(query);

Then, register your Notification Callback.

cQ.RegisterClearNotification(new ContinuousQueryClearCallback(CacheCleared));

RegisterNotification(QueryDataNotificationCallback, EventType, EventDataFilter)

This method registers a custom callback that is fired on change in dataset of a Continuous Query.

Declaration
public void RegisterNotification(QueryDataNotificationCallback callback, EventType eventType, EventDataFilter datafilter)
Parameters
Type Name Description
QueryDataNotificationCallback callback

A delegate to register your custom method with.
EventType eventType

Describes whether the event is to be raised when an item is added, updated, or removed.
EventDataFilter datafilter

This enum is to describe when registering an event, upon raise how much data is retrieved from cache when the event is raised.
Examples

The following example shows how to register the notification callback. First, create an ItemCallback.

ItemCallback(string key, CacheEventArg e)
{
   ...
}

Then declare your Continuous Query.

ContinuousQuery cQ=new ContinuousQuery(query,Hashtable vals);

Then register your Notification Callback.

cQ.RegisterNotification(new QueryDataNotificationCallback(ItemCallback),EventType.ItemAdded, EventDataFilter.None);

UnRegisterClearNotification(ContinuousQueryClearCallback)

This method Unregisters the clear callback.

Declaration
public void UnRegisterClearNotification(ContinuousQueryClearCallback callback)
Parameters
Type Name Description
ContinuousQueryClearCallback callback

A delegate to register your custom method with.
Examples

The following example shows how to register a ClearNotification.

 public static void CacheCleared()
  {
    ...
  }

Next, you can unregister your Notification Callback as shown.

cQ.UnRegisterClearNotification(new ContinuousQueryClearCallback(CacheCleared));

UnRegisterNotification(QueryDataNotificationCallback, EventType)

This method Unregisters a custom callback that is fired on change in dataset of a Continuous Query.

Declaration
public void UnRegisterNotification(QueryDataNotificationCallback callback, EventType eventType)
Parameters
Type Name Description
QueryDataNotificationCallback callback

A delegate to register your custom method with.
EventType eventType

Describes whether the event is to be raised when an item is added, updated, or removed.
Examples

Lets consider we created an ItemCallback.

ItemCallback(string key, CacheEventArg e)
{
   ...
}

Unregister your notification callback.

cQ.RegisterNotification(new QueryDataNotificationCallback(ItemCallback),EventType.ItemAdded);