org.apache.commons.digester3.plugins
Class PluginCreateRule

java.lang.Object
  org.apache.commons.digester3.Rule
      org.apache.commons.digester3.plugins.PluginCreateRule

All Implemented Interfaces:

InitializableRule

public class PluginCreateRule
extends Rule
implements InitializableRule

Allows the original rules for parsing the configuration file to define points at which plugins are allowed, by configuring a PluginCreateRule with the appropriate pattern.

Since:

1.6

Constructor Summary

PluginCreateRule(Class<?> baseClass)
Create a plugin rule where the user must specify a plugin-class or plugin-id.

PluginCreateRule(Class<?> baseClass, Class<?> dfltPluginClass)
Create a plugin rule where the user may specify a plugin.

PluginCreateRule(Class<?> baseClass, Class<?> dfltPluginClass, RuleLoader dfltPluginRuleLoader)
Create a plugin rule where the user may specify a plugin.

Method Summary

void	begin(String namespace, String name, Attributes attributes) Invoked when the Digester matches this rule against an xml element.
void	body(String namespace, String name, String text) This method is called when the body of a matching XML element is encountered.
void	end(String namespace, String name) This method is called when the end of a matching XML element is encountered.
void	fireBeginMethods(List<Rule> rules, String namespace, String name, Attributes list) Duplicate the processing that the Digester does when firing the begin methods of rules.
void	fireEndMethods(List<Rule> rules, String namespaceURI, String name) Duplicate the processing that the Digester does when firing the end methods of rules.
String	getPattern() Return the pattern that this Rule is associated with.
void	postRegisterInit(String matchPattern) Called after this Rule object has been added to the list of all Rules.
void	setPluginClassAttribute(String namespaceUri, String attrName) Sets the xml attribute which the input xml uses to indicate to a PluginCreateRule which class should be instantiated.
void	setPluginIdAttribute(String namespaceUri, String attrName) Sets the xml attribute which the input xml uses to indicate to a PluginCreateRule which plugin declaration is being referenced.

Methods inherited from class org.apache.commons.digester3.Rule

finish, getDigester, getNamespaceURI, setDigester, setNamespaceURI

Methods inherited from class java.lang.Object

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

Constructor Detail

PluginCreateRule

public PluginCreateRule(Class<?> baseClass)

Create a plugin rule where the user must specify a plugin-class or plugin-id.

Parameters:

baseClass - is the class which any specified plugin must be descended from.

PluginCreateRule

public PluginCreateRule(Class<?> baseClass,
                        Class<?> dfltPluginClass)

Create a plugin rule where the user may specify a plugin. If the user doesn't specify a plugin, then the default class specified in this constructor is used.

Parameters:

baseClass - is the class which any specified plugin must be descended from.

dfltPluginClass - is the class which will be used if the user doesn't specify any plugin-class or plugin-id. This class will have custom rules installed for it just like a declared plugin.

PluginCreateRule

public PluginCreateRule(Class<?> baseClass,
                        Class<?> dfltPluginClass,
                        RuleLoader dfltPluginRuleLoader)

Create a plugin rule where the user may specify a plugin. If the user doesn't specify a plugin, then the default class specified in this constructor is used.

Parameters:

baseClass - is the class which any specified plugin must be descended from.

dfltPluginClass - is the class which will be used if the user doesn't specify any plugin-class or plugin-id. This class will have custom rules installed for it just like a declared plugin.

dfltPluginRuleLoader - is a RuleLoader instance which knows how to load the custom rules associated with this default plugin.

Method Detail

setPluginClassAttribute

public void setPluginClassAttribute(String namespaceUri,
                                    String attrName)

Sets the xml attribute which the input xml uses to indicate to a PluginCreateRule which class should be instantiated.

See PluginRules.setPluginClassAttribute(java.lang.String, java.lang.String) for more info.

Parameters:

namespaceUri - is the namespace uri that the specified attribute is in. If the attribute is in no namespace, then this should be null. Note that if a namespace is used, the attrName value should not contain any kind of namespace-prefix. Note also that if you are using a non-namespace-aware parser, this parameter must be null.

attrName - is the attribute whose value contains the name of the class to be instantiated.

setPluginIdAttribute

public void setPluginIdAttribute(String namespaceUri,
                                 String attrName)

Sets the xml attribute which the input xml uses to indicate to a PluginCreateRule which plugin declaration is being referenced.

See PluginRules.setPluginIdAttribute(java.lang.String, java.lang.String) for more info.

Parameters:

namespaceUri - is the namespace uri that the specified attribute is in. If the attribute is in no namespace, then this should be null. Note that if a namespace is used, the attrName value should not contain any kind of namespace-prefix. Note also that if you are using a non-namespace-aware parser, this parameter must be null.

attrName - is the attribute whose value contains the id of the plugin declaration to be used when instantiating an object.

postRegisterInit

public void postRegisterInit(String matchPattern)

Called after this Rule object has been added to the list of all Rules. Note that if a single InitializableRule instance is associated with more than one pattern, then this method will be called more than once.

Specified by:

postRegisterInit in interface InitializableRule

Parameters:

matchPattern - is the digester match pattern that will trigger this rule.

begin

public void begin(String namespace,
                  String name,
                  Attributes attributes)
           throws Exception

Invoked when the Digester matches this rule against an xml element.

A new instance of the target class is created, and pushed onto the stack. A new "private" PluginRules object is then created and set as the digester's default Rules object. Any custom rules associated with the plugin class are then loaded into that new Rules object. Finally, any custom rules that are associated with the current pattern (such as SetPropertiesRules) have their begin methods executed.

Overrides:

begin in class Rule

Parameters:

namespace - the namespace URI of the matching element, or an empty string if the parser is not namespace aware or the element has no namespace

name - the local name if the parser is namespace aware, or just the element name otherwise

attributes - The attribute list of this element

Throws:

Exception - if any error occurs

body

public void body(String namespace,
                 String name,
                 String text)
          throws Exception

This method is called when the body of a matching XML element is encountered. If the element has no body, this method is called with an empty string as the body text.

Overrides:

body in class Rule

Parameters:

namespace - the namespace URI of the matching element, or an empty string if the parser is not namespace aware or the element has no namespace

name - the local name if the parser is namespace aware, or just the element name otherwise

text - The text of the body of this element

Throws:

Exception - if any error occurs

end

public void end(String namespace,
                String name)
         throws Exception

This method is called when the end of a matching XML element is encountered.

Overrides:

end in class Rule

Parameters:

namespace - the namespace URI of the matching element, or an empty string if the parser is not namespace aware or the element has no namespace

name - the local name if the parser is namespace aware, or just the element name otherwise

Throws:

Exception - if any error occurs

getPattern

public String getPattern()

Return the pattern that this Rule is associated with.

In general, Rule instances can be associated with multiple patterns. A PluginCreateRule, however, will only function correctly when associated with a single pattern. It is possible to fix this, but I can't be bothered just now because this feature is unlikely to be used.

Returns:

The pattern value

fireBeginMethods

public void fireBeginMethods(List<Rule> rules,
                             String namespace,
                             String name,
                             Attributes list)
                      throws Exception

Duplicate the processing that the Digester does when firing the begin methods of rules. It would be really nice if the Digester class provided a way for this functionality to just be invoked directly.

Parameters:

rules - The rules which Rule.begin(String, String, Attributes) method has to be fired

namespace - the namespace URI of the matching element, or an empty string if the parser is not namespace aware or the element has no namespace

name - the local name if the parser is namespace aware, or just the element name otherwise

list - The attribute list of this element

Throws:

Exception - if any error occurs

fireEndMethods

public void fireEndMethods(List<Rule> rules,
                           String namespaceURI,
                           String name)
                    throws Exception

Duplicate the processing that the Digester does when firing the end methods of rules. It would be really nice if the Digester class provided a way for this functionality to just be invoked directly.

Parameters:

rules - The rules which Rule.end(String, String) method has to be fired

namespaceURI - the namespace URI of the matching element, or an empty string if the parser is not namespace aware or the element has no namespace

name - the local name if the parser is namespace aware, or just the element name otherwise

Throws:

Exception - if any error occurs