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

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

All Implemented Interfaces:

org.apache.avalon.framework.component.Component, org.apache.avalon.framework.configuration.Configurable, org.apache.avalon.framework.activity.Disposable, InputModule, org.apache.avalon.framework.logger.LogEnabled

Direct Known Subclasses:

RequestModule, SessionModule, SystemPropertyModule

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

Configuration example:

<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.

Version:

$Id: AbstractJXPathModule.java,v 1.3.2.3 2002/12/06 09:20:01 cziegeler Exp $

Author:

Konstantin Piroumian, Christian Haul

Field Summary

protected org.apache.commons.jxpath.FunctionLibrary

library Contains all globally registered extension classes and packages.

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(org.apache.avalon.framework.configuration.Configuration config) Configure component.
java.lang.Object	getAttribute(java.lang.String name, org.apache.avalon.framework.configuration.Configuration modeConf, java.util.Map objectModel) Standard access to an attribute's value.
java.util.Iterator	getAttributeNames(org.apache.avalon.framework.configuration.Configuration modeConf, java.util.Map objectModel) Returns an Iterator of String objects containing the names of the attributes available.
java.lang.Object[]	getAttributeValues(java.lang.String name, org.apache.avalon.framework.configuration.Configuration modeConf, java.util.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 java.lang.Object	getContextObject(org.apache.avalon.framework.configuration.Configuration modeConf, java.util.Map objectModel) Returns the object which should be used as JXPath context.
protected void	getFunctions(org.apache.commons.jxpath.FunctionLibrary lib, org.apache.avalon.framework.configuration.Configuration conf) Register all extension functions listed in the configuration through <function name="fully.qualified.Class" prefix="prefix"/> in the given FunctionLibrary.
protected void	getPackages(org.apache.commons.jxpath.FunctionLibrary lib, org.apache.avalon.framework.configuration.Configuration conf) Register all extension packages listed in the configuration through <package name="fully.qualified.package" prefix="prefix"/> in the given FunctionLibrary.
protected void	setupExtensions(org.apache.commons.jxpath.JXPathContext context, org.apache.avalon.framework.configuration.Configuration conf) Actually add global functions and packages as well as those listed in the configuration object.

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

library

protected org.apache.commons.jxpath.FunctionLibrary library

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

Constructor Detail

AbstractJXPathModule

public AbstractJXPathModule()

Method Detail

configure

public void configure(org.apache.avalon.framework.configuration.Configuration config)
               throws org.apache.avalon.framework.configuration.ConfigurationException

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

Overrides:

configure in class AbstractInputModule

Parameters:

conf - a Configuration value

Throws:

org.apache.avalon.framework.configuration.ConfigurationException - if an error occurs

getFunctions

protected void getFunctions(org.apache.commons.jxpath.FunctionLibrary lib,
                            org.apache.avalon.framework.configuration.Configuration conf)

Register all extension functions listed in the configuration through <function name="fully.qualified.Class" prefix="prefix"/> in the given FunctionLibrary.

Parameters:

lib - a FunctionLibrary value

conf - a Configuration value

getPackages

protected void getPackages(org.apache.commons.jxpath.FunctionLibrary lib,
                           org.apache.avalon.framework.configuration.Configuration conf)

Register all extension packages listed in the configuration through <package name="fully.qualified.package" prefix="prefix"/> in the given FunctionLibrary.

Parameters:

lib - a FunctionLibrary value

conf - a Configuration value

setupExtensions

protected void setupExtensions(org.apache.commons.jxpath.JXPathContext context,
                               org.apache.avalon.framework.configuration.Configuration conf)

Actually add global functions and packages as well as those listed in the configuration object.

Parameters:

context - a JXPathContext value

conf - a Configuration value holding local packages and functions.

getAttribute

public java.lang.Object getAttribute(java.lang.String name,
                                     org.apache.avalon.framework.configuration.Configuration modeConf,
                                     java.util.Map objectModel)
                              throws org.apache.avalon.framework.configuration.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 getAttributeSet or getAttributeNames and getAttribute to get them one by one.

Following copied from interface: org.apache.cocoon.components.modules.input.InputModule

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.

objectModel -

getAttributeNames

public java.util.Iterator getAttributeNames(org.apache.avalon.framework.configuration.Configuration modeConf,
                                            java.util.Map objectModel)
                                     throws org.apache.avalon.framework.configuration.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.

Following copied from interface: org.apache.cocoon.components.modules.input.InputModule

Parameters:

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

objectModel -

getAttributeValues

public java.lang.Object[] getAttributeValues(java.lang.String name,
                                             org.apache.avalon.framework.configuration.Configuration modeConf,
                                             java.util.Map objectModel)
                                      throws org.apache.avalon.framework.configuration.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, getAttributeNames together with getAttribute can be used to get the values one by one.

Following copied from interface: org.apache.cocoon.components.modules.input.InputModule

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.

objectModel -

getContextObject

protected abstract java.lang.Object getContextObject(org.apache.avalon.framework.configuration.Configuration modeConf,
                                                     java.util.Map objectModel)
                                              throws org.apache.avalon.framework.configuration.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.