Package org.apache.commons.digester.plugins

Class 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 Detail

      • digester

        protected Digester digester
        The Digester instance with which this Rules instance is associated.

      • rulesFactory

        private RulesFactory rulesFactory
        The (optional) object which generates new rules instances.

      • 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​(Digester digester,
            java.lang.String mountPoint,
            PluginRules parent,
            java.lang.Class<?> pluginClass)
     throws PluginException
        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:
        digester - is the object this rules will be associated with.
        mountPoint - is the digester match path for the element matching a PluginCreateRule which caused this "nested parsing scope" to begin. This is expected to be equal to digester.getMatch().
        parent - must be non-null.
        pluginClass - is the plugin class whose custom rules will be loaded into this new PluginRules object.
        Throws:
        PluginException

    • 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

      • getRulesFactory

        public RulesFactory getRulesFactory()
        Return the rules factory object (or null if one has not been specified).

      • setRulesFactory

        public void setRulesFactory​(RulesFactory factory)
        Set the object which is used to generate the new Rules instances created to hold and process the rules associated with each plugged-in class.

      • 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<Rule> 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

        @Deprecated
public java.util.List<Rule> 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<Rule> 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.