org.objectweb.cjdbc.controller.loadbalancer.policies.errorchecking
Class ErrorCheckingPolicy

java.lang.Object
  org.objectweb.cjdbc.controller.loadbalancer.policies.errorchecking.ErrorCheckingPolicy

Direct Known Subclasses:

ErrorCheckingAll, ErrorCheckingRandom, ErrorCheckingRoundRobin

public abstract class ErrorCheckingPolicy

extends java.lang.Object

Defines the policy to adopt for error checking.

Version:

1.0

Author:

Emmanuel Cecchet

Field Summary

static int	ALL Request is sent to all backends.
protected int	nbOfNodes Number of nodes that are involved in error-checking per request.
protected int	policy
static int	RANDOM Pickup backends randomly.
static int	ROUND_ROBIN Backends are chosen using a round-robin algorithm.

Constructor Summary

ErrorCheckingPolicy(int policy, int numberOfNodes)
Creates a new CreateTableRule.

Method Summary

abstract java.util.ArrayList	getBackends(java.util.ArrayList backends) Pickups backends from the given backends arraylist according to the current rule policy.
abstract java.lang.String	getInformation() Gives information about the current policy.
int	getNumberOfNodes() Returns the number of nodes.
int	getPolicy() Returns the policy.
java.lang.String	getXml() Convert this error checking policy to xml
void	setNumberOfNodes(int numberOfNodes) Sets the number of nodes.
void	setPolicy(int policy) Sets the policy.

Methods inherited from class java.lang.Object

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

Field Detail

RANDOM

public static final int RANDOM

Pickup backends randomly.

See Also:

Constant Field Values

ROUND_ROBIN

public static final int ROUND_ROBIN

Backends are chosen using a round-robin algorithm.

See Also:

Constant Field Values

ALL

public static final int ALL

Request is sent to all backends.

See Also:

Constant Field Values

nbOfNodes

protected int nbOfNodes

Number of nodes that are involved in error-checking per request.

policy

protected int policy

Constructor Detail

ErrorCheckingPolicy

public ErrorCheckingPolicy(int policy,
                           int numberOfNodes)

Creates a new CreateTableRule.

Parameters:

policy - implemented policy

numberOfNodes - number of nodes to use to check for errors on a query

Method Detail

getNumberOfNodes

public int getNumberOfNodes()

Returns the number of nodes.

Returns:

an int value

See Also:

setNumberOfNodes(int)

setNumberOfNodes

public void setNumberOfNodes(int numberOfNodes)

Sets the number of nodes.

Parameters:

numberOfNodes - the number of nodes to set

See Also:

getNumberOfNodes()

getPolicy

public int getPolicy()

Returns the policy.

Returns:

an int value

See Also:

setPolicy(int)

setPolicy

public void setPolicy(int policy)

Sets the policy.

Parameters:

policy - the policy to set

See Also:

getPolicy()

getBackends

public abstract java.util.ArrayList getBackends(java.util.ArrayList backends)
                                         throws ErrorCheckingException

Pickups backends from the given backends arraylist according to the current rule policy.

Parameters:

backends - backends to choose from

Returns:

Arraylist of choosen DatabaseBackend

Throws:

ErrorCheckingException - if the rule cannot be applied

getInformation

public abstract java.lang.String getInformation()

Gives information about the current policy.

Returns:

a String value

getXml

public java.lang.String getXml()

Convert this error checking policy to xml

Returns:

xml formatted string