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

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

All Implemented Interfaces:

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

public class JXPathMetaModule

extends AbstractMetaModule

implements org.apache.avalon.framework.configuration.Configurable

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. This is based on the AbstractJXPathModule and duplicates the code since multiple inheritance is not possible. Please keep both classes in sync.

Configuration example:

<input-module name="request-attr" parameter="foo"/>	Uses the "request-attr" input module to obtain parameter named "foo" and applies the given JXPath expression to it.
<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: JXPathMetaModule.java,v 1.1.2.2 2002/12/06 09:27:30 cziegeler Exp $

Author:

Konstantin Piroumian, Christian Haul

Field Summary

protected org.apache.commons.jxpath.FunctionLibrary	library Contains all globally registered extension classes and packages.
protected java.lang.String	parameter

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

defaultInput, initialized, input, INPUT_MODULE_SELECTOR, inputConf, inputSelector, manager

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

JXPathMetaModule()

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 java.lang.Object	getContextObject(org.apache.avalon.framework.configuration.Configuration modeConf, java.util.Map objectModel) Looks up object from configured InputModule.
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.AbstractMetaModule

compose, dispose, getNames, getNames, getValue, getValue, getValues, getValues, initialize, obtainModule, releaseModule

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.

parameter

protected java.lang.String parameter

Constructor Detail

JXPathMetaModule

public JXPathMetaModule()

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.

Specified by:

configure in interface org.apache.avalon.framework.configuration.Configurable

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

Looks up object from configured InputModule.

Parameters:

modeConf - a Configuration value

objectModel - a Map value

Returns:

an Object value