FunctionService (GemFire Java API Documentation)

java.lang.Object
- com.gemstone.gemfire.cache.execute.FunctionService

```
public final class FunctionService
extends Object
```
Provides the entry point into execution of user defined Functions.
Function execution provides a means to route application behaviour to data or more generically to peers in a DistributedSystem or servers in a Pool.

Since:

6.0

Method Summary

Methods
Modifier and Type	Method and Description
`static Function`	`getFunction(String functionId)` Returns the `Function` defined by the functionId, returns null if no function is found for the specified functionId
`static Map<String,Function>`	`getRegisteredFunctions()` Returns all locally registered functions
`static boolean`	`isRegistered(String functionId)` Returns true if the function is registered to FunctionService
`static Execution`	`onMember(DistributedMember distributedMember)` Returns an `Execution` object that can be used to execute a data independent function on a `DistributedMember`.
`static Execution`	`onMember(DistributedSystem system, DistributedMember distributedMember)` Deprecated. use `onMember(DistributedMember)` instead
`static Execution`	`onMember(String... groups)` Returns an `Execution` object that can be used to execute a data independent function on one member of each group provided.
`static Execution`	`onMembers(DistributedSystem system)` Deprecated. use `onMember(String...)` instead
`static Execution`	`onMembers(DistributedSystem system, Set<DistributedMember> distributedMembers)` Deprecated. use `onMembers(Set)` instead
`static Execution`	`onMembers(Set<DistributedMember> distributedMembers)` Returns an `Execution` object that can be used to execute a data independent function on the set of `DistributedMember`s.
`static Execution`	`onMembers(String... groups)` Returns an `Execution` object that can be used to execute a data independent function on all peer members.
`static Execution`	`onRegion(Region region)` Returns an `Execution` object that can be used to execute a data dependent function on the specified Region.
`static Execution`	`onServer(Pool pool)` Returns an `Execution` object that can be used to execute a data independent function on a server in the provided `Pool`.
`static Execution`	`onServer(RegionService regionService)` Returns an `Execution` object that can be used to execute a data independent function on a server that the given cache is connected to.
`static Execution`	`onServers(Pool pool)` Returns an `Execution` object that can be used to execute a data independent function on all the servers in the provided `Pool`.
`static Execution`	`onServers(RegionService regionService)` Returns an `Execution` object that can be used to execute a data independent function on all the servers that the given cache is connected to.
`static void`	`registerFunction(Function function)` Registers the given `Function` with the `FunctionService` using `Function.getId()`.
`static void`	`unregisterFunction(String functionId)` Unregisters the given `Function` with the `FunctionService` using `Function.getId()`.

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - onRegion
```
public static Execution onRegion(Region region)
```
    Returns an Execution object that can be used to execute a data dependent function on the specified Region.
    When invoked from a GemFire client, the method returns an Execution instance that sends a message to one of the connected servers as specified by the Pool for the region.
    Depending on the filters setup on the Execution, the function is executed on all GemFire members that define the data region, or a subset of members. Execution.withFilter(Set)). For DistributedRegions with DataPolicy.NORMAL, it throws UnsupportedOperationException. For DistributedRegions with DataPolicy.EMPTY, execute the function on any random member which has DataPolicy.REPLICATE
    . For DistributedRegions with DataPolicy.REPLICATE, execute the function locally. For Regions with DataPolicy.PARTITION, it executes on members where the data resides as specified by the filter.
    
    Parameters:
    region -
    
    Returns:
    Execution
    
    Throws:
    
    FunctionException - if the region passed in is null
    Since:
    
    6.0
  - onServer
```
public static Execution onServer(Pool pool)
```
    Returns an Execution object that can be used to execute a data independent function on a server in the provided Pool.
    If the server goes down while dispatching or executing the function, an Exception will be thrown.
    
    Parameters:
    pool - from which to chose a server for execution
    
    Returns:
    Execution
    
    Throws:
    
    FunctionException - if Pool instance passed in is null
    Since:
    
    6.0
  - onServers
```
public static Execution onServers(Pool pool)
```
    Returns an Execution object that can be used to execute a data independent function on all the servers in the provided Pool. If one of the servers goes down while dispatching or executing the function on the server, an Exception will be thrown.
    
    Parameters:
    pool - the set of servers to execute the function
    
    Returns:
    Execution
    
    Throws:
    
    FunctionException - if Pool instance passed in is null
    Since:
    
    6.0
  - onServer
```
public static Execution onServer(RegionService regionService)
```
    Returns an Execution object that can be used to execute a data independent function on a server that the given cache is connected to.
    If the server goes down while dispatching or executing the function, an Exception will be thrown.
    
    Parameters:
    regionService - obtained from ClientCacheFactory.create() or ClientCache.createAuthenticatedView(Properties).
    
    Returns:
    Execution
    
    Throws:
    
    FunctionException - if cache is null, is not on a client, or it does not have a default pool
    Since:
    
    6.5
  - onServers
```
public static Execution onServers(RegionService regionService)
```
    Returns an Execution object that can be used to execute a data independent function on all the servers that the given cache is connected to. If one of the servers goes down while dispatching or executing the function on the server, an Exception will be thrown.
    
    Parameters:
    regionService - obtained from ClientCacheFactory.create() or ClientCache.createAuthenticatedView(Properties).
    
    Returns:
    Execution
    
    Throws:
    
    FunctionException - if cache is null, is not on a client, or it does not have a default pool
    Since:
    
    6.5
  - onMember
```
public static Execution onMember(DistributedSystem system,
                 DistributedMember distributedMember)
```
    Deprecated. use onMember(DistributedMember) instead
    
    Returns an Execution object that can be used to execute a data independent function on a DistributedMember of the DistributedSystem. If the member is not found in the system, the function execution will throw an Exception. If the member goes down while dispatching or executing the function on the member, an Exception will be thrown.
    
    Parameters:
    system - defines the distributed system
    distributedMember - defines a member in the distributed system
    
    Returns:
    Execution
    
    Throws:
    
    FunctionException - if either input parameter is null
    Since:
    
    6.0
  - onMembers
```
public static Execution onMembers(DistributedSystem system)
```
    Deprecated. use onMember(String...) instead
    
    Returns an Execution object that can be used to execute a data independent function on all members of the DistributedSystem. If one of the members goes down while dispatching or executing the function on the member, an Exception will be thrown.
    
    Parameters:
    system - defines the distributed system
    
    Returns:
    Execution
    
    Throws:
    
    FunctionException - if DistributedSystem instance passed is null
    Since:
    
    6.0
  - onMembers
```
public static Execution onMembers(DistributedSystem system,
                  Set<DistributedMember> distributedMembers)
```
    Deprecated. use onMembers(Set) instead
    
    Returns an Execution object that can be used to execute a data independent function on the set of DistributedMembers of the DistributedSystem. If one of the members goes down while dispatching or executing the function, an Exception will be thrown.
    
    Parameters:
    system - defines the distributed system
    distributedMembers - set of distributed members on which Function to be executed
    
    Throws:
    
    FunctionException - if DistributedSystem instance passed is null
    Since:
    
    6.0
  - onMember
```
public static Execution onMember(DistributedMember distributedMember)
```
    Returns an Execution object that can be used to execute a data independent function on a DistributedMember. If the member is not found, executing the function will throw an Exception. If the member goes down while dispatching or executing the function on the member, an Exception will be thrown.
    
    Parameters:
    distributedMember - defines a member in the distributed system
    
    Returns:
    Execution
    
    Throws:
    
    FunctionException - if distributedMember is null
    Since:
    
    7.0
  - onMembers
```
public static Execution onMembers(String... groups)
```
    Returns an Execution object that can be used to execute a data independent function on all peer members. If the optional groups parameter is provided, function is executed on all members that belong to the provided groups.
    If one of the members goes down while dispatching or executing the function on the member, an Exception will be thrown.
    
    Parameters:
    groups - optional list of GemFire configuration property "groups" (see groups) on which to execute the function. Function will be executed on all members of each group
    
    Returns:
    Execution
    
    Throws:
    
    FunctionException - if no members are found belonging to the provided groups
    Since:
    
    7.0
  - onMembers
```
public static Execution onMembers(Set<DistributedMember> distributedMembers)
```
    Returns an Execution object that can be used to execute a data independent function on the set of DistributedMembers. If one of the members goes down while dispatching or executing the function, an Exception will be thrown.
    
    Parameters:
    distributedMembers - set of distributed members on which Function to be executed
    
    Throws:
    
    FunctionException - if distributedMembers is null
    Since:
    
    7.0
  - onMember
```
public static Execution onMember(String... groups)
```
    Returns an Execution object that can be used to execute a data independent function on one member of each group provided.
    
    Parameters:
    groups - list of GemFire configuration property "groups" (see groups) on which to execute the function. Function will be executed on one member of each group
    
    Returns:
    Execution
    
    Throws:
    
    FunctionException - if no members are found belonging to the provided groups
    Since:
    
    7.0
  - getFunction
```
public static Function getFunction(String functionId)
```
    Returns the Function defined by the functionId, returns null if no function is found for the specified functionId
    
    Parameters:
    functionId -
    
    Returns:
    Function
    
    Throws:
    
    FunctionException - if functionID passed is null
    Since:
    
    6.0
  - registerFunction
```
public static void registerFunction(Function function)
```
    Registers the given Function with the FunctionService using Function.getId().
    Registering a function allows execution of the function using Execution.execute(String). Every member that could execute a function using its Function.getId() should register the function.
    
    Throws:
    
    FunctionException - if function instance passed is null or Function.getId() returns null
    Since:
    
    6.0
  - unregisterFunction
```
public static void unregisterFunction(String functionId)
```
    Unregisters the given Function with the FunctionService using Function.getId().
    
    Throws:
    
    FunctionException - if function instance passed is null or Function.getId() returns null
    Since:
    
    6.0
  - isRegistered
```
public static boolean isRegistered(String functionId)
```
    Returns true if the function is registered to FunctionService
    
    Throws:
    
    FunctionException - if function instance passed is null or Function.getId() returns null
    Since:
    
    6.0
  - getRegisteredFunctions
```
public static Map<String,Function> getRegisteredFunctions()
```
    Returns all locally registered functions
    
    Returns:
    A view of registered functions as a Map of Function.getId() to Function
    Since:
    
    6.0

Class FunctionService

Method Summary

Methods inherited from class java.lang.Object

Method Detail

onRegion

onServer

onServers

onServer

onServers

onMember

onMembers

onMembers

onMember

onMembers

onMembers

onMember

getFunction

registerFunction

unregisterFunction

isRegistered

getRegisteredFunctions