org.apache.commons.digester.plugins
Class PluginCreateRule

java.lang.Object
  extended by org.apache.commons.digester.Rule
      extended by org.apache.commons.digester.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

Field Summary
 
Fields inherited from class org.apache.commons.digester.Rule
digester, namespaceURI
 
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)
          Process the body text of this element.
 void end(String namespace, String name)
          Invoked by the digester when the closing tag matching this Rule's pattern is encountered.
 void fireBeginMethods(List rules, String namespace, String name, Attributes list)
          Duplicate the processing that the Digester does when firing the begin methods of rules.
 void fireEndMethods(List 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)
          Invoked after this rule has been added to the set of digester rules, associated with the specified pattern.
 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.digester.Rule
begin, body, end, 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.


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.


postRegisterInit

public void postRegisterInit(String matchPattern)
                      throws PluginConfigurationException
Invoked after this rule has been added to the set of digester rules, associated with the specified pattern. Check all configuration data is valid and remember the pattern for later.

Specified by:
postRegisterInit in interface InitializableRule
Parameters:
matchPattern - is the digester match pattern that is associated with this rule instance, eg "root/widget".
Throws:
PluginConfigurationException

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 -
name -
attributes -
Throws:
ClassNotFoundException
PluginInvalidInputException
PluginConfigurationException
Exception

body

public void body(String namespace,
                 String name,
                 String text)
          throws Exception
Process the body text of this element.

Overrides:
body in class Rule
Parameters:
text - The body text of this element
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

end

public void end(String namespace,
                String name)
         throws Exception
Invoked by the digester when the closing tag matching this Rule's pattern is encountered.

Overrides:
end in class Rule
Parameters:
namespace - Description of the Parameter
name - Description of the Parameter
Throws:
Exception - Description of the Exception
See Also:
begin(java.lang.String, java.lang.String, org.xml.sax.Attributes)

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 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.

Throws:
Exception

fireEndMethods

public void fireEndMethods(List 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.

Throws:
Exception


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