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

java.lang.Object
  org.apache.cocoon.util.AbstractLogEnabled
      org.apache.cocoon.components.modules.input.AbstractInputModule
          org.apache.cocoon.components.modules.input.AbstractMetaModule
              org.apache.cocoon.components.modules.input.ChainMetaModule

All Implemented Interfaces:

Configurable, Disposable, org.apache.cocoon.components.modules.input.InputModule, Serviceable, ThreadSafe

public class ChainMetaModule

extends org.apache.cocoon.components.modules.input.AbstractMetaModule

implements ThreadSafe

This modules allows to "chain" several other modules. If a module returns "null" as attribute value, the next module in the chain is queried until either a value can be obtained or the end of the chain is reached.

A typical example would be to "chain" request parameters, session attributes, and constants in this order. This way, an application could have a default skin that could be overridden by a user in her/his profile stored in the session. In addition, the user could request a different skin through passing a request parameter.

Usage:

Any number of <input-module/> blocks may appear in the component configuration. The @name attribute is used as the name of the requested input module. The complete <input-module/> block is passed at run-time to the module and thus can contain any configuration data for that particular module.

Configuration:

It can be controlled whether it returns a flat or a deep view, i.e. whether only values from the first module are returned if non-null or they are merged with values from other modules <all-values>true</all-values>. The same is possible for the attribute names (<all-names/>). In addition, empty strings could be treated the same as null values (<empty-as-null/>).

Version:

$Id: ChainMetaModule.html 1304280 2012-03-23 11:18:01Z ilgrosso $

Field Summary

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

ChainMetaModule()

Method Summary

void	configure(Configuration config)
void	dispose()
Object	getAttribute(String attr, Configuration modeConf, Map objectModel)
Iterator	getAttributeNames(Configuration modeConf, Map objectModel)
Object[]	getAttributeValues(String attr, Configuration modeConf, Map objectModel)
void	lazy_initialize()

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

getNames, getNames, getValue, getValue, getValue, getValue, getValues, getValues, getValues, getValues, obtainModule, releaseModule, service

Methods inherited from class org.apache.cocoon.util.AbstractLogEnabled

getLogger, setLogger

Methods inherited from class java.lang.Object

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

Constructor Detail

ChainMetaModule

public ChainMetaModule()

Method Detail

configure

public void configure(Configuration config)
               throws ConfigurationException

Specified by:

configure in interface Configurable

Throws:

ConfigurationException

See Also:

AbstractInputModule.configure(org.apache.avalon.framework.configuration.Configuration)

lazy_initialize

public void lazy_initialize()

See Also:

AbstractMetaModule.lazy_initialize()

dispose

public void dispose()

Specified by:

dispose in interface Disposable

See Also:

AbstractMetaModule.dispose()

getAttributeValues

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

Specified by:

getAttributeValues in interface org.apache.cocoon.components.modules.input.InputModule

Throws:

ConfigurationException

See Also:

AbstractInputModule.getAttributeValues(java.lang.String, org.apache.avalon.framework.configuration.Configuration, java.util.Map)

getAttributeNames

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

Specified by:

getAttributeNames in interface org.apache.cocoon.components.modules.input.InputModule

Throws:

ConfigurationException

See Also:

AbstractInputModule.getAttributeNames(org.apache.avalon.framework.configuration.Configuration, java.util.Map)

getAttribute

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

Specified by:

getAttribute in interface org.apache.cocoon.components.modules.input.InputModule

Throws:

ConfigurationException