de.aristaflow.adept2.util

Class AristaFlowExpressionEngine

java.lang.Object

org.apache.commons.configuration2.tree.DefaultExpressionEngine

de.aristaflow.adept2.util.AristaFlowExpressionEngine

All Implemented Interfaces:

ExpressionEngine

public class AristaFlowExpressionEngine
extends DefaultExpressionEngine

An expression engine for hierarchical configurations of Apache Commons Configuration. Usually the default uses some intelligence to support indexed and attribute access in keys. We do not need this at all. However, we cannot just set the default expression engine. This is set statically. Therefore a customer may override our expression engine or we may override the expression engine of a customer. Neither is desired, we have to set the expression engine on an instance basis rather than on the class basis.

Important! Since a HierarchicalConfiguration creates new instances for subsets, make sure to set our expression engine after retrieving a subset.

Field Summary

Fields inherited from class org.apache.commons.configuration2.tree.DefaultExpressionEngine

INSTANCE

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AristaFlowExpressionEngine() Creates a new expression engine for a HierarchicalConfiguration disabling attributes and indexes.

Method Summary

Modifier and Type	Method and Description
static Configuration	setExpressionEngine(Configuration conf) Sets a new expression engine for the designated configuration.

Methods inherited from class org.apache.commons.configuration2.tree.DefaultExpressionEngine

attributeKey, canonicalKey, findLastPathNode, findNodesForKey, getSymbols, nodeKey, prepareAdd, query

Methods inherited from class java.lang.Object

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

Constructor Detail

AristaFlowExpressionEngine

protected AristaFlowExpressionEngine()

Creates a new expression engine for a HierarchicalConfiguration disabling attributes and indexes.

Method Detail

setExpressionEngine

public static Configuration setExpressionEngine(Configuration conf)

Sets a new expression engine for the designated configuration. The expression engine is only relevant for AristaFlowExpressionEngines.
Note that this method has to be called for every new subset of a configuration. A HierarchicalConfiguration creates new instances in this case which do not inherit the expression engine of the parent configuration.

Parameters:

conf - The configuration in which to set a new expression engine if appropriate.

Returns:

The designated configuration which allows to call this method in the call of the super-constructor.