org.apache.cocoon.components.modules.input
Class AbstractJXPathModule

java.lang.Object
  org.apache.avalon.framework.logger.AbstractLogEnabled
      org.apache.cocoon.components.modules.input.AbstractInputModule
          org.apache.cocoon.components.modules.input.AbstractJXPathModule

All Implemented Interfaces:

Disposable, Component, Configurable, LogEnabled, InputModule

Direct Known Subclasses:

FlowAttributeModule, FlowContinuationModule, PropertiesFileModule, RequestModule, SessionModule, SystemPropertyModule, XMLFileModule

public abstract class AbstractJXPathModule
extends AbstractInputModule

JXPathModule allows to access properties of any object in generic way. JXPath provides APIs for the traversal of graphs of JavaBeans, DOM and other types of objects using the XPath syntax.

Note: JXPathMetaModule is based on this class and duplicates the code since multiple inheritance is not possible. Please keep both classes in sync.

Configuration

<lenient>false</lenient>	When set to true, non-existing attributes return null; when set to false, an exception is thrown. Default is true.
<parameter>foo</parameter>	When set overrides attribute name passed to module.
<function name="java.lang.String" prefix="str"/>	Imports the class "String" as extension class to the JXPathContext using the prefix "str". Thus "str:length(xpath)" would apply the method "length" to the string object obtained from the xpath expression. Please note that the class needs to be fully qualified.
<package name="java.util" prefix="util"/>	Imports all classes in the package "java.util" as extension classes to the JXPathContext using the prefix "util". Thus "util:Date.new()" would create a new java.util.Date object.
<namespace uri="uri:foo" prefix="bar"/>	Registers the namespace identified by URI uri:foo with the JXPathContext using the prefix bar. Thus expressions can query XML with nodes in this namespace using registered prefix.

Version:

$Id: AbstractJXPathModule.html 1304258 2012-03-23 10:09:27Z ilgrosso $

Author:

Konstantin Piroumian, Christian Haul, Vadim Gritsenko

Field Summary

protected JXPathHelperConfiguration	configuration Contains all globally registered extension classes and packages.
protected String	parameter Overrides attribute name

Fields inherited from class org.apache.cocoon.components.modules.input.AbstractInputModule

settings

Fields inherited from interface org.apache.cocoon.components.modules.input.InputModule

ROLE

Constructor Summary

AbstractJXPathModule()

Method Summary

void	configure(Configuration config) Configure component.
Object	getAttribute(String name, Configuration modeConf, Map objectModel) Standard access to an attribute's value.
Iterator	getAttributeNames(Configuration modeConf, Map objectModel) Returns an Iterator of String objects containing the names of the attributes available.
Object[]	getAttributeValues(String name, Configuration modeConf, Map objectModel) Returns an array of String objects containing all of the values the given attribute has, or null if the attribute does not exist.
protected abstract Object	getContextObject(Configuration modeConf, Map objectModel) Returns the object which should be used as JXPath context.

Methods inherited from class org.apache.cocoon.components.modules.input.AbstractInputModule

dispose

Methods inherited from class org.apache.avalon.framework.logger.AbstractLogEnabled

enableLogging, getLogger, setupLogger, setupLogger, setupLogger

Methods inherited from class java.lang.Object

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

Field Detail

configuration

protected JXPathHelperConfiguration configuration

Contains all globally registered extension classes and packages. Thus the lookup and loading of globally registered extensions is done only once.

parameter

protected String parameter

Overrides attribute name

Constructor Detail

AbstractJXPathModule

public AbstractJXPathModule()

Method Detail

configure

public void configure(Configuration config)
               throws ConfigurationException

Configure component. Preprocess list of packages and functions to add to JXPath context later.

Specified by:

configure in interface Configurable

Overrides:

configure in class AbstractInputModule

Parameters:

config - a Configuration value

Throws:

ConfigurationException - if an error occurs

getAttribute

public Object getAttribute(String name,
                           Configuration modeConf,
                           Map objectModel)
                    throws ConfigurationException

Description copied from interface: InputModule

Standard access to an attribute's value. If more than one value exists, the first is returned. If the value does not exist, null is returned. To get all values, use InputModule.getAttributeValues(String, Configuration, Map) or InputModule.getAttributeNames(Configuration, Map) and InputModule.getAttribute(String, Configuration, Map) to get them one by one.

Specified by:

getAttribute in interface InputModule

Overrides:

getAttribute in class AbstractInputModule

Parameters:

name - a String that specifies what the caller thinks would identify an attribute. This is mainly a fallback if no modeConf is present.

modeConf - column's mode configuration from resource description. This argument is optional.

Throws:

ConfigurationException

getAttributeNames

public Iterator getAttributeNames(Configuration modeConf,
                                  Map objectModel)
                           throws ConfigurationException

Description copied from interface: InputModule

Returns an Iterator of String objects containing the names of the attributes available. If no attributes are available, the method returns an empty Iterator.

Specified by:

getAttributeNames in interface InputModule

Overrides:

getAttributeNames in class AbstractInputModule

Parameters:

modeConf - column's mode configuration from resource description. This argument is optional.

Throws:

ConfigurationException

getAttributeValues

public Object[] getAttributeValues(String name,
                                   Configuration modeConf,
                                   Map objectModel)
                            throws ConfigurationException

Description copied from interface: InputModule

Returns an array of String objects containing all of the values the given attribute has, or null if the attribute does not exist. As an alternative, InputModule.getAttributeNames(Configuration, Map) together with InputModule.getAttribute(String, Configuration, Map) can be used to get the values one by one.

Specified by:

getAttributeValues in interface InputModule

Overrides:

getAttributeValues in class AbstractInputModule

Parameters:

name - a String that specifies what the caller thinks would identify an attributes. This is mainly a fallback if no modeConf is present.

modeConf - column's mode configuration from resource description. This argument is optional.

Throws:

ConfigurationException

getContextObject

protected abstract Object getContextObject(Configuration modeConf,
                                           Map objectModel)
                                    throws ConfigurationException

Returns the object which should be used as JXPath context. Descendants should override this method to return a specific object that is requried by the implementing class. Examples are: request, session and application context objects.

Throws:

ConfigurationException