org.apache.commons.digester.plugins
Class PluginRules

java.lang.Object
  |
  +--org.apache.commons.digester.plugins.PluginRules

All Implemented Interfaces:

Rules

public class PluginRules

extends java.lang.Object

implements Rules

A custom digester Rules manager which must be used as the Rules object when using the plugins module functionality.

During parsing, a linked list of PluginCreateRule instances develop, and this list also acts like a stack. The original instance that was set before the Digester started parsing is always at the tail of the list, and the Digester always holds a reference to the instance at the head of the list in the rules member. Initially, this list/stack holds just one instance, ie head and tail are the same object.

When the start of an xml element causes a PluginCreateRule to fire, a new PluginRules instance is created and inserted at the head of the list (ie pushed onto the stack of Rules objects). Digester.getRules() therefore returns this new Rules object, and any custom rules associated with that plugin are added to that instance.

When the end of the xml element is encountered (and therefore the PluginCreateRule end method fires), the stack of Rules objects is popped, so that Digester.getRules returns the previous Rules object.

Since:

1.6

Field Summary

private Rules	decoratedRules The rules implementation that we are "enhancing" with plugins functionality, as per the Decorator pattern.
protected Digester	digester The Digester instance with which this Rules instance is associated.
private java.lang.String	mountPoint The path below which this rules object has responsibility.
private PluginRules	parent The Rules object that holds rules applying "above" the mountpoint, ie the next Rules object down in the stack.
private PluginContext	pluginContext A reference to the object that holds all data which should only exist once per digester instance.
private PluginManager	pluginManager Object which contains information about all known plugins.

Constructor Summary

	PluginRules() Constructor for top-level Rules objects.
	PluginRules(Rules decoratedRules) Constructor for top-level Rules object which handles rule-matching using the specified implementation.
(package private)	PluginRules(java.lang.String mountPoint, PluginRules parent) Constructs a Rules instance which has a parent Rules object (which is different from having a delegate rules object).

Method Summary

void	add(java.lang.String pattern, Rule rule) Register a new Rule instance matching the specified pattern.
void	clear() Clear all rules.
(package private) Rules	getDecoratedRules() This package-scope method is used by the PluginCreateRule class to get direct access to the rules that were dynamically added by the plugin.
Digester	getDigester() Return the Digester instance with which this instance is associated.
java.lang.String	getNamespaceURI() Return the namespace URI that will be applied to all subsequently added Rule objects.
Rules	getParent() Return the parent Rules object.
java.lang.String	getPluginClassAttr() See PluginContext.getPluginClassAttr().
java.lang.String	getPluginClassAttrNs() See PluginContext.getPluginClassAttrNs().
java.lang.String	getPluginIdAttr() See PluginContext.getPluginIdAttr().
java.lang.String	getPluginIdAttrNs() See PluginContext.getPluginIdAttrNs().
PluginManager	getPluginManager() Return the object which "knows" about all declared plugins.
java.util.List	getRuleFinders() See PluginContext.getRuleFinders().
java.util.List	match(java.lang.String path) Deprecated. Call match(namespaceURI,pattern) instead.
java.util.List	match(java.lang.String namespaceURI, java.lang.String path) Return a List of all registered Rule instances that match the specified nodepath, or a zero-length List if there are no matches.
java.util.List	rules() Return the list of rules registered with this object, in the order they were registered with this object.
void	setDigester(Digester digester) Set the Digester instance with which this Rules instance is associated.
void	setNamespaceURI(java.lang.String namespaceURI) Set the namespace URI that will be applied to all subsequently added Rule objects.
void	setPluginClassAttribute(java.lang.String namespaceUri, java.lang.String attrName) See PluginContext.setPluginClassAttribute(java.lang.String, java.lang.String).
void	setPluginIdAttribute(java.lang.String namespaceUri, java.lang.String attrName) See PluginContext.setPluginIdAttribute(java.lang.String, java.lang.String).
void	setRuleFinders(java.util.List ruleFinders) See PluginContext.setRuleFinders(java.util.List).

Methods inherited from class java.lang.Object

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

Field Detail

digester

protected Digester digester

The Digester instance with which this Rules instance is associated.

decoratedRules

private Rules decoratedRules

The rules implementation that we are "enhancing" with plugins functionality, as per the Decorator pattern.

pluginManager

private PluginManager pluginManager

Object which contains information about all known plugins.

mountPoint

private java.lang.String mountPoint

The path below which this rules object has responsibility. For paths shorter than or equal the mountpoint, the parent's match is called.

parent

private PluginRules parent

The Rules object that holds rules applying "above" the mountpoint, ie the next Rules object down in the stack.

pluginContext

private PluginContext pluginContext

A reference to the object that holds all data which should only exist once per digester instance.

Constructor Detail

PluginRules

public PluginRules()

Constructor for top-level Rules objects. Exactly one of these must be created and installed into the Digester instance as the Rules object before parsing starts.

PluginRules

public PluginRules(Rules decoratedRules)

Constructor for top-level Rules object which handles rule-matching using the specified implementation.

PluginRules

PluginRules(java.lang.String mountPoint,
            PluginRules parent)

Constructs a Rules instance which has a parent Rules object (which is different from having a delegate rules object).

One of these is created each time a PluginCreateRule's begin method fires, in order to manage the custom rules associated with whatever concrete plugin class the user has specified.

Parameters:

mountPoint - is the digester match path for the element matching a PluginCreateRule which caused this "nested parsing scope" to begin.

parent - must be non-null.

Method Detail

getParent

public Rules getParent()

Return the parent Rules object.

getDigester

public Digester getDigester()

Return the Digester instance with which this instance is associated.

Specified by:

getDigester in interface Rules

setDigester

public void setDigester(Digester digester)

Set the Digester instance with which this Rules instance is associated.

Specified by:

setDigester in interface Rules

Parameters:

digester - The newly associated Digester instance

getNamespaceURI

public java.lang.String getNamespaceURI()

Return the namespace URI that will be applied to all subsequently added Rule objects.

Specified by:

getNamespaceURI in interface Rules

setNamespaceURI

public void setNamespaceURI(java.lang.String namespaceURI)

Set the namespace URI that will be applied to all subsequently added Rule objects.

Specified by:

setNamespaceURI in interface Rules

Parameters:

namespaceURI - Namespace URI that must match on all subsequently added rules, or null for matching regardless of the current namespace URI

getPluginManager

public PluginManager getPluginManager()

Return the object which "knows" about all declared plugins.

Returns:

The pluginManager value

getRuleFinders

public java.util.List getRuleFinders()

See PluginContext.getRuleFinders().

setRuleFinders

public void setRuleFinders(java.util.List ruleFinders)

See PluginContext.setRuleFinders(java.util.List).

getDecoratedRules

Rules getDecoratedRules()

This package-scope method is used by the PluginCreateRule class to get direct access to the rules that were dynamically added by the plugin. No other class should need access to this object.

rules

public java.util.List rules()

Return the list of rules registered with this object, in the order they were registered with this object.

Note that Rule objects stored in parent Rules objects are not returned by this method.

Specified by:

rules in interface Rules

Returns:

list of all Rule objects known to this Rules instance.

add

public void add(java.lang.String pattern,
                Rule rule)

Register a new Rule instance matching the specified pattern.

Specified by:

add in interface Rules

Parameters:

pattern - Nesting pattern to be matched for this Rule. This parameter treats equally patterns that begin with and without a leading slash ('/').

rule - Rule instance to be registered

clear

public void clear()

Clear all rules.

Specified by:

clear in interface Rules

match

public java.util.List match(java.lang.String path)

Deprecated. Call match(namespaceURI,pattern) instead.

Return a List of all registered Rule instances that match the specified nesting pattern, or a zero-length List if there are no matches. If more than one Rule instance matches, they must be returned in the order originally registered through the add() method.

Specified by:

match in interface Rules

Parameters:

path - the path to the xml nodes to be matched.

match

public java.util.List match(java.lang.String namespaceURI,
                            java.lang.String path)

Return a List of all registered Rule instances that match the specified nodepath, or a zero-length List if there are no matches. If more than one Rule instance matches, they must be returned in the order originally registered through the add() method.

Specified by:

match in interface Rules

Parameters:

namespaceURI - Namespace URI for which to select matching rules, or null to match regardless of namespace URI

path - the path to the xml nodes to be matched.

setPluginClassAttribute

public void setPluginClassAttribute(java.lang.String namespaceUri,
                                    java.lang.String attrName)

See PluginContext.setPluginClassAttribute(java.lang.String, java.lang.String).

setPluginIdAttribute

public void setPluginIdAttribute(java.lang.String namespaceUri,
                                 java.lang.String attrName)

See PluginContext.setPluginIdAttribute(java.lang.String, java.lang.String).

getPluginClassAttrNs

public java.lang.String getPluginClassAttrNs()

See PluginContext.getPluginClassAttrNs().

getPluginClassAttr

public java.lang.String getPluginClassAttr()

See PluginContext.getPluginClassAttr().

getPluginIdAttrNs

public java.lang.String getPluginIdAttrNs()

See PluginContext.getPluginIdAttrNs().

getPluginIdAttr

public java.lang.String getPluginIdAttr()

See PluginContext.getPluginIdAttr().