cacheperf.comparisons.replicated.execute

Class GetEntryFunction

java.lang.Object

cacheperf.comparisons.replicated.execute.GetEntryFunction

All Implemented Interfaces:

com.gemstone.gemfire.cache.Declarable, com.gemstone.gemfire.cache.execute.Function, com.gemstone.gemfire.lang.Identifiable<String>, Serializable

public class GetEntryFunction
extends Object
implements com.gemstone.gemfire.cache.execute.Function, com.gemstone.gemfire.cache.Declarable

A function to mimic the behavior of a simple get() on a PartitionedRegion. Use of this function assures that get() operations always occur on the Primary node for the given key, and addresses two issues:

Work-around for PR Expiration limitation, whereby get() operations that occur on a secondary copy of an Entry do not reset the Expiration Timer TTL.

Work-around for PR Expiration problem discovered during SWA Session Caching application testing. The problem discovered does not happen when get operations always occur on the Primary node for the target key.

To register this function declaratively in a GFE peer, server, or client process, add the following to the cache.xml file:

" "com.swacorp.session.poc.gemfire.GetEntryFunction" "

On the Java client, the function should be invoked by the String methodId, rather than by passing-in an actual instance of the function (this would cause the function itself to be serialized and sent to the invocation target, which is only useful for dynamically created functions or functions not previously registered on the server).

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static String	ID The well-known String function identifier used to make invocations.

Constructor Summary

Constructors

Constructor and Description
GetEntryFunction()

Method Summary

Modifier and Type	Method and Description
void	execute(com.gemstone.gemfire.cache.execute.FunctionContext context) Returns the Entry Value that corresponds with the given Key (as passed-in via the function Filter).
String	getId() Return the well-known String function identifier used to make invocations.
boolean	hasResult() True as we always return the Entry Value (or null if not found).
void	init(Properties properties) Required by Declarable Interface, but not used in this case as all resources, context, and inputs provided at invocation time.
boolean	isHA() Enables automated re-tries if the invocation fails from the caller's perspective (for example, if the remote server or a connection fails mid-execution).
boolean	optimizeForWrite() Returning TRUE instructs GemFire to always invoke the function on the node that owns the Primary copy of the Entry Key filter passed into the function invocation.

Methods inherited from class java.lang.Object

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

Field Detail

ID

public static final String ID

The well-known String function identifier used to make invocations.

See Also:

Constant Field Values

Constructor Detail

GetEntryFunction

public GetEntryFunction()

Method Detail

execute

public void execute(com.gemstone.gemfire.cache.execute.FunctionContext context)

Returns the Entry Value that corresponds with the given Key (as passed-in via the function Filter). Note that passing in the key by this mechanism (rather than as a user argument to the function) lets the "data-aware" function routing hint simultaneously act as BOTH a hint AND the function argument.

Specified by:

execute in interface com.gemstone.gemfire.cache.execute.Function

getId

public String getId()

Return the well-known String function identifier used to make invocations.

Specified by:

getId in interface com.gemstone.gemfire.cache.execute.Function

Specified by:

getId in interface com.gemstone.gemfire.lang.Identifiable<String>

optimizeForWrite

public boolean optimizeForWrite()

Returning TRUE instructs GemFire to always invoke the function on the node that owns the Primary copy of the Entry Key filter passed into the function invocation.

Specified by:

optimizeForWrite in interface com.gemstone.gemfire.cache.execute.Function

isHA

public boolean isHA()

Enables automated re-tries if the invocation fails from the caller's perspective (for example, if the remote server or a connection fails mid-execution). This simulates the behavior of a generic "get()" operation.

Specified by:

isHA in interface com.gemstone.gemfire.cache.execute.Function

hasResult

public boolean hasResult()

True as we always return the Entry Value (or null if not found). FYI: If not TRUE, then the invocation fires-and-forgets from the caller's perspective. This method is thus a way that GFE optimizes processing for the calling thread.

Specified by:

hasResult in interface com.gemstone.gemfire.cache.execute.Function

init

public void init(Properties properties)

Required by Declarable Interface, but not used in this case as all resources, context, and inputs provided at invocation time.

Specified by:

init in interface com.gemstone.gemfire.cache.Declarable