wt.rule.impl
Class DefaultRuleSelector

java.lang.Object
  wt.rule.impl.DefaultRuleSelector

All Implemented Interfaces:

RuleSelector

public class DefaultRuleSelector

extends Object

implements RuleSelector

This is a default implementation of the RuleSelector interface.

This class has public visibility due to an implementation side effect. This class should have package visibility. Do not create instances of this class directly. Instead use the wt.rule.RuleSelectorFactory class to obtain an instance.

Given a target object O and a rule type R, this delegate picks a rule from the set of default enabled rules of type R based on the following precedence rules:

1. InstanceBasedRule that references O
2. InstanceBasedRule that references O's master
3. TypeBasedRule that references O's class

If no rule is found in the specified container, then its parent container is searched. This repeats until a rule is found or the top of the hierarchy is reached. If a rule cannot be found then null is returned.

Supported API: false

Extendable: false

Field Summary

private static String	CLASSNAME
private static String	RESOURCE
private static String	RULE_RESOURCE

Constructor Summary

DefaultRuleSelector()

Method Summary

private static InstanceBasedRule	findIBR(RuleType ruleType, Persistable object, WTContainerRef container) Find the default-enabled InstanceBasedRule that satisfies the specified search criteria.
private static TypeBasedRule	findTBR(RuleType ruleType, Class objType, WTContainerRef container) Find the default-enabled TypeBasedRule that satisfies the specified search criteria.
Rule	getRule(Object object, RuleType ruleType, WTContainerRef container) Select a rule of type ruleType that is applicable to object.

Methods inherited from class java.lang.Object

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

Field Detail

RESOURCE

private static final String RESOURCE

See Also:

Constant Field Values

CLASSNAME

private static final String CLASSNAME

RULE_RESOURCE

private static final String RULE_RESOURCE

See Also:

Constant Field Values

Constructor Detail

DefaultRuleSelector

public DefaultRuleSelector()

Method Detail

getRule

public Rule getRule(Object object,
                    RuleType ruleType,
                    WTContainerRef container)
             throws WTException

Select a rule of type ruleType that is applicable to object. If no rule can be found, return null.

The object argument may be a type identifier or a normal object. A type identifier is one of the following:

• Class
• TypeIdentifier
• String specifying the name of the type

Different implementations of this interface will use the criteria in different ways to select a rule.

Specified by:

getRule in interface RuleSelector

Parameters:

object - the object that the rule should be applicable to (cannot be null)

ruleType - the type of rule to select (cannot be null)

container - the container in which to search for the rule

Returns:

Rule

Throws:

WTException

findIBR

private static final InstanceBasedRule findIBR(RuleType ruleType,
                                               Persistable object,
                                               WTContainerRef container)
                                        throws WTException

Find the default-enabled InstanceBasedRule that satisfies the specified search criteria. Start the search for the rule in the specified container. Continue the search up the hierarchy until a rule is found or the top of the hierarchy is reached.

Parameters:

ruleType -

object -

container - the container to start searching in

Returns:

InstanceBasedRule

Throws:

WTException

findTBR

private static final TypeBasedRule findTBR(RuleType ruleType,
                                           Class objType,
                                           WTContainerRef container)
                                    throws WTException

Find the default-enabled TypeBasedRule that satisfies the specified search criteria. Start the search for the rule in the specified container. Continue the search up the hierarchy until a rule is found or the top of the hierarchy is reached.

Parameters:

ruleType -

objType -

container - the container to start searching in

Returns:

TypeBasedRule

Throws:

WTException