Cache Management XML definition

Owned by kiran.kumari@intellectdesign.com (Unlicensed)
Last updated: Sept 20, 2018

The cache configuration is centered on a XML structure that defines the various caches. The following code segment is a sample XML –for cache configuration:

<?xml version="1.0" encoding="UTF-8"?> 
<AllCaches>
	<Cache Id="MY_CACHE_ID" Scope="application" Preload="Y">
	<Handler>com.intellectdesign.myapp.MyCacheSourceHandler</Handler>
	<HandlerParams>
		<Param Name="MY_PARAM_1">Param 1 Value</Param>
		<Param Name="MY_PARAM_2">Param 2 Value</Param>
	</HandlerParams>
	</Cache>
</AllCaches>


Let us look at each of the element of the Cache Management XML.

XML Element: AllCaches

This is the root element within the cache configuration XML. The attributes and child elements supported at the root element are:

Key

Relation Type

Multiplicity

Purpose

mode

Attribute

–

This is an optional attribute that is set at the root element to indicate whether the cache should make remote connections for invocation of its handler. Possible values are:

  • local – This is the default value. This means that the web and application components are deployed together and no remote calls are needed.
  • remote – If this value is provided, then the bean CacheDelegateEJB and its related configuration (like JNDI, etc.) needs to be activated and provided for the Cache framework. This is required to make a remote call for fetching the cache data.

Cache

Child Element

1..n

This is the child element under the root that indicates a cache definition.


The following code segment is a sample –for the AllCaches element:

<?xml version="1.0" encoding="UTF-8"?> 
<AllCaches mode="local">
</AllCaches>

XML Element: Cache

This is the child element under the root that indicates a cache definition. One entry corresponds to a single cache definition. The attributes and child elements supported by the Cache element are:

Key

Relation Type

Multiplicity

Purpose

Id

Attribute

–

This is the unique ID for the cache within the Cache Management layer. All access to the cache from within the application is done using this ID.

Scope

Attribute

–

This is a mandatory attribute that indicates the scope of the cache being defined. Possible values are:

  • application – Indicates that the cache is an application level cache.
  • session – Indicates that the cache is a session-level cache.

Preload

Attribute

–

This is a Flag attribute at a cache level that indicates whether the cache should be loaded at startup of the Caching system. Possible values are:

  • Y – Indicates that the cache should be initialized at startup.
  • N – Indicates that the cache needs to be initialized at first access.

ExpiryInterval

Attribute

–

This attribute indicates the time in milliseconds post which the cache is to be considered stale. If not provided or if the value is 0, the cache is considered to be in sync with its data for ever after initial load.

Validating

Attribute

–

This is a flag attribute at a cache level that indicates whether the cache has to check for data staleness before returning the data. This provides a hook to the handler for reporting the staleness of the cache and based on the handler feedback returns the cache data or reloads the data into the cache. Possible values are:

  • Y – Indicates that the cache is validating the data before returning it.
  • N – Indicates that the cache is not validating the data before returning it. This is the default value.

Handler

Child Element

1

This is a child of the Cache element. This is the Java class that will provide the data for the cache. This is a mandatory configuration to be provided for a cache.

HandlerParams

Child Element

0..1

This is a child of the Cache element. This is an optional element that can be used for passing any parameters to the handler for the handler's execution. The parameters are user-defined. The handler can validate the parameters provided at the time of XML parsing and initialization itself before the parameters are used.


The following code segment is a sample entry –for the Cache element:

<?xml version="1.0" encoding="UTF-8"?> 
<AllCaches>
	<Cache Id="MY_CACHE_ID" Scope="application" Preload="Y" ExpiryInterval="10000" Validating="N">
	</Cache>
</AllCaches>


The options Preload, ExpiryInterval, and Validating are not applicable for caches defined with the scope as session. If provided, these are ignored.

XML Element: Handler

This is a child of the Cache element. This is the Java class that provides the data for the cache. This is a mandatory configuration to be provided for a cache. The class provided should be a sub-class of com.intellectdesign.canvas.cache.handler.CacheDataBuilder. This element does not support any attributes or child elements.
The following code segment is a sample entry –for the Handler element:

<?xml version="1.0" encoding="UTF-8"?> 
<AllCaches>
	<Cache Id="MY_CACHE_ID" Scope="application" Preload="Y" ExpiryInterval="10000" Validating="N">
	<Handler>com.intellectdesign.myapp.MyCacheSourceHandler</Handler>
	</Cache>
</AllCaches>


XML Element: HandlerParams

This is a child of the Cache element. This is an optional element that can be used for passing any parameters to the handler for the handler's execution. The parameters are user-defined. The handler can validate the parameters provided at the time of XML parsing and initialization itself before the parameters are used. The attributes and child elements supported by this element are:

Key

Relation Type

Multiplicity

Purpose

Param

Child Element

1..n

This is a child of the HandlerParam element. If the HandlerParam is provided, then one or more parameters have to be defined. This has a Name attribute for defining the parameter name and the element value is the parameter value.

Name

Attribute

–

This is the attribute associated with the Param element for defining the name of the parameter. If there are duplicates, then the value that will be used is indeterminate.


The following code segment is a sample entry –for the HandlerParams element:

<?xml version="1.0" encoding="UTF-8"?> 
<AllCaches>
	<Cache Id="MY_CACHE_ID" Scope="application" Preload="Y" ExpiryInterval="10000" Validating="N">
	<Handler>com.intellectdesign.myapp.MyCacheSourceHandler</Handler>
		<HandlerParams>
		<Param Name="MY_PARAM_1">Param 1 Value</Param>
		<Param Name="MY_PARAM_2">Param 2 Value</Param>
		</HandlerParams>
	</Cache>
</AllCaches>