com.ibm.di.server
Class ReconnectRuleEngine

java.lang.Object
  com.ibm.di.server.ReconnectRuleEngine

public class ReconnectRuleEngine
extends java.lang.Object

This class decides what to do when a connector raises an error. Possible actions are to attempt a reconnect or leave the error unhandled and let further mechanisms process it.

The class makes decisions based on configured rules. Each rule describes what should be done when an error occurs. Each rule applies to certain connectors and certain errors. In a rule the connectors are described by their base Java class and their name in the current configuration. (there are match-all options for both the class and the name of the connector). A rule describes applicable errors by their base Java class and a regular expression that matches their messages (the regular expression is optional).

The reconnect engine holds two collections of rules: in-built rules and user-defined rules.

The in-built rules are defined in an '.inf' file in the jar file of the corresponding connector. They are specific to that connector class. In order to preserver the reconnect behaviour, which existed before the introduction of ReconnectRuleEngine, when the engine is created, it implicitly adds to the in-built rules rules, which prescribe to attempt reconnect on all IOException-s and all CommunicationException-s.

The user defined rules reside in an external text file.

Field Summary

static int	ERROR the situation is a fatal error which no reconnect could fix
static java.lang.String	ERROR_STRING error action - no reconnect will be attempted
static int	INVALID_RECONNECT_ACTION invalid reconnect action
static int	RECONNECT reconnect should be attempted to fix the error situation
static char	RECONNECT_RULE_PARTS_DELIMETER the delimiter of the parts of a rule in the config file
static java.lang.String	RECONNECT_STRING reconnect action - if an error occurs reconnect will be attempted

Constructor Summary

ReconnectRuleEngine(Log log)
Constructor, which loads the in-built rules and the user-defined rules.

Method Summary

int	getReconnectChoice(ConnectorInterface connector, java.lang.Throwable error) This method prescribes a response action for a given error situation.
void	loadRules(java.lang.String userDefinedRulesFilePath, MetamergeConfig sysConfig) Loads the in-built and the user-defined rules.

Methods inherited from class java.lang.Object

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

Field Detail

INVALID_RECONNECT_ACTION

public static final int INVALID_RECONNECT_ACTION

invalid reconnect action

See Also:

Constant Field Values

ERROR

public static final int ERROR

the situation is a fatal error which no reconnect could fix

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Constant Field Values

RECONNECT

public static final int RECONNECT

reconnect should be attempted to fix the error situation

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Constant Field Values

RECONNECT_RULE_PARTS_DELIMETER

public static final char RECONNECT_RULE_PARTS_DELIMETER

the delimiter of the parts of a rule in the config file

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Constant Field Values

ERROR_STRING

public static final java.lang.String ERROR_STRING

error action - no reconnect will be attempted

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Constant Field Values

RECONNECT_STRING

public static final java.lang.String RECONNECT_STRING

reconnect action - if an error occurs reconnect will be attempted

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Constant Field Values

Constructor Detail

ReconnectRuleEngine

public ReconnectRuleEngine(Log log)

Constructor, which loads the in-built rules and the user-defined rules.

Parameters:

log - a log object to be used during the lifetime of the engine

Method Detail

loadRules

public void loadRules(java.lang.String userDefinedRulesFilePath,
                      MetamergeConfig sysConfig)
               throws java.lang.Exception

Loads the in-built and the user-defined rules.

Parameters:

userDefinedRulesFilePath - the file with user-defined rules

sysConfig - system configuration object, which has the in-built rules of all connectors

Throws:

java.lang.Exception - problem while parsing the configured rules ClassNotFoundException problem while loading an exception/connector class, specified in a rule

getReconnectChoice

public int getReconnectChoice(ConnectorInterface connector,
                              java.lang.Throwable error)

This method prescribes a response action for a given error situation.

First searches the user-defined rules and if no matching rule is found, the method searches the Connector own rules. If a rule cannot be found in either collection, the default action (ERROR) is prescribed.

When a collection (in-built or user-defined) is searched for a matching rule, first is sought a match for the error itself. If no match is found for the error and the error has a specified cause (getCause() returns non-null) then a match for the cause is searched. Only when both searched fail, another collection of rules is considered.

Parameters:

connector - the connector, which raised the error

error - the error object

Returns:

the prescribed action - it is one of the following: ERROR or RECONNECT