com.ibm.di.server
Class ReconnectRuleEngine

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

public class ReconnectRuleEngine
extends 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 String	ERROR_STRING
static int	INVALID_RECONNECT_ACTION
static int	RECONNECT reconnect should be attempted to fix the error situation
static char	RECONNECT_RULE_PARTS_DELIMETER the delimeter of the parts of a rule in the config file
static String	RECONNECT_STRING

Constructor Summary

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

Method Summary

int	getReconnectChoice(Class connectorClass, String connectorName, Throwable error) This method prescribes a response action for a given error situation.
void	loadRules(String userDefinedRulesFilePath, MetamergeConfig sysConfig) Loads the in-built and the user-defined rules.
static String	rulesToTextInUserDefinedRuleFormat(String connectorClassName, Object rulesConfig) Parses the in-built reconnect rules for a given connector and transforms them to a text in the format for user-defined rules (each rule resides on a single line).

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

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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 delimeter of the parts of a rule in the config file

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Constant Field Values

ERROR_STRING

public static final String ERROR_STRING

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Constant Field Values

RECONNECT_STRING

public static final String RECONNECT_STRING

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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(String userDefinedRulesFilePath,
                      MetamergeConfig sysConfig)
               throws 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:

Exception - problem while parsing the confgured rules ClassNotFoundException problem while loading an exception/connector class, specified in a rule

getReconnectChoice

public int getReconnectChoice(Class connectorClass,
                              String connectorName,
                              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 in-built 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:

connectorClass - the Java class of the connector, which raised the error

connectorName - the name of the connector as it is specified in the configuration file of the solution

error - the error object

Returns:

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

rulesToTextInUserDefinedRuleFormat

public static String rulesToTextInUserDefinedRuleFormat(String connectorClassName,
                                                        Object rulesConfig)
                                                 throws Exception

Parses the in-built reconnect rules for a given connector and transforms them to a text in the format for user-defined rules (each rule resides on a single line).

Parameters:

connectorClassName - the fully qualified name of the Java class of the connector

rulesConfig - the configuration structure which holds the in-built reconnect rules of the connector (it is supposed to be a list of maps)

Returns:

all rules as text in user-defined rules format

Throws:

problem - with the reconnect rules

Exception