org.jboss.dna.repository.rules
Class RuleSetRepositoryMonitor

java.lang.Object
  org.jboss.dna.repository.rules.RuleSetRepositoryMonitor

All Implemented Interfaces:

NodeChangeListener

@ThreadSafe
public class RuleSetRepositoryMonitor
extends Object
implements NodeChangeListener

A component that can listen to a JCR repository and keep the RuleSet instances of a RuleService synchronized with that repository.

This class is a NodeChangeListener that can subscribe to changes in one or more JCR repositories being monitored by an ObservationService. As changes under the rule sets branch are discovered, they are processed asynchronously. This ensure that the processing of the repository contents does not block the other listeners of the ObservationService.

Author:

Randall Hauch

Field Summary

static String	DEFAULT_JCR_ABSOLUTE_PATH
protected static String	JCR_PATH_DELIM

Constructor Summary

RuleSetRepositoryMonitor(RuleService ruleService, String jcrAbsolutePath, JcrExecutionContext executionContext)
Create an instance that can listen to the RuleSet definitions stored in a JCR repository and ensure that the RuleSet instances of a RuleService reflect the definitions in the repository.

Method Summary

protected RuleSet	buildRuleSet(String name, javax.jcr.Node ruleSetNode, JcrTools tools) Create a rule set from the supplied node.
String	getAbsolutePathToRuleSets()
org.jboss.dna.common.util.Logger	getLogger()
RuleService	getRuleService()
void	onNodeChanges(NodeChanges changes)
protected void	processRuleSets(Map<String,Set<String>> ruleSetNamesByWorkspaceName) Process the rule sets given by the supplied names, keyed by the repository workspace name.
void	setLogger(org.jboss.dna.common.util.Logger logger)

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_JCR_ABSOLUTE_PATH

public static final String DEFAULT_JCR_ABSOLUTE_PATH

See Also:

Constant Field Values

JCR_PATH_DELIM

protected static final String JCR_PATH_DELIM

See Also:

Constant Field Values

Constructor Detail

RuleSetRepositoryMonitor

public RuleSetRepositoryMonitor(RuleService ruleService,
                                String jcrAbsolutePath,
                                JcrExecutionContext executionContext)

Create an instance that can listen to the RuleSet definitions stored in a JCR repository and ensure that the RuleSet instances of a RuleService reflect the definitions in the repository.

Parameters:

ruleService - the rule service that should be kept in sync with the JCR repository.

jcrAbsolutePath - the absolute path to the branch where the rule sets are defined; if null or empty, the default path is used

executionContext - the context in which this monitor is to execute

Throws:

IllegalArgumentException - if the rule service or execution context is null, or if the supplied jcrAbsolutePath is invalid

Method Detail

getRuleService

public RuleService getRuleService()

Returns:

ruleService

getAbsolutePathToRuleSets

public String getAbsolutePathToRuleSets()

Returns:

jcrAbsolutePath

getLogger

public org.jboss.dna.common.util.Logger getLogger()

Returns:

logger

setLogger

public void setLogger(org.jboss.dna.common.util.Logger logger)

Parameters:

logger - Sets logger to the specified value.

onNodeChanges

public void onNodeChanges(NodeChanges changes)

Specified by:

onNodeChanges in interface NodeChangeListener

processRuleSets

protected void processRuleSets(Map<String,Set<String>> ruleSetNamesByWorkspaceName)

Process the rule sets given by the supplied names, keyed by the repository workspace name.

Parameters:

ruleSetNamesByWorkspaceName - the set of rule set names keyed by the repository workspace name

buildRuleSet

protected RuleSet buildRuleSet(String name,
                               javax.jcr.Node ruleSetNode,
                               JcrTools tools)

Create a rule set from the supplied node. This is called whenever a branch of the repository is changed.

This implementation expects a node of type 'dna:ruleSet' and the following properties (expressed as XPath statements relative to the supplied node):

• The description is obtained from the "./@jcr:description" string property. This property is optional.
• The classname is obtained from the "./@dna:classname" string property. This property is required.
• The classpath is obtained from the "./@dna:classpath" string property. This property is optional, and if abscent then the classpath will be assumed from the current context.
• The provider URI is obtained from the "./@dna:serviceProviderUri" string property, and corresponds to the URI of the JSR-94 rules engine service provider. This property is required.
• The rule set URI is obtained from the "./@dna:ruleSetUri" string property. This property is optional and defaults to the node name (e.g., "./@jcr:name").
• The definition of the rules is obtained from the "./@dna:rules" string property. This property is required and must be in a form suitable for the JSR-94 rules engine.
• The properties are obtained from the "./dna:properties[contains(@jcr:mixinTypes,'dna:propertyContainer')]/*[@jcr:nodeType='dna:property']" property nodes, where the name of the property is extracted from the property node's "./@jcr:name" string property and the value of the property is extracted from the property node's "./@dna:propertyValue" string property. Rule set properties are optional.

Parameters:

name - the name of the rule set; never null

ruleSetNode - the node representing the rule set; null if the rule set doesn't exist

tools -

Returns:

the rule set for the information stored in the repository, or null if the rule set does not exist or has errors