Package org.apache.commons.configuration2

Class ConfigurationLookup

java.lang.Object

org.apache.commons.configuration2.ConfigurationLookup

All Implemented Interfaces:

Lookup

public class ConfigurationLookup
extends Object
implements Lookup

A specialized implementation of the Lookup interface which uses a Configuration object to resolve variables.

This class is passed an ImmutableConfiguration object at construction time. In its implementation of the lookup() method it simply queries this configuration for the passed in variable name. So the keys passed to lookup() are mapped directly to configuration properties.

Since:

2.0

Constructor Summary

Constructors

Constructor	Description
ConfigurationLookup(ImmutableConfiguration config)	Creates a new instance of ConfigurationLookup and sets the associated ImmutableConfiguration.

Method Summary

Modifier and Type	Method	Description
ImmutableConfiguration	getConfiguration()	Gets the ImmutableConfiguration used by this object.
Object	lookup(String variable)	Looks up the value of the specified variable.

Methods inherited from class java.lang.Object

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

Constructor Details

ConfigurationLookup

public ConfigurationLookup(ImmutableConfiguration config)

Creates a new instance of ConfigurationLookup and sets the associated ImmutableConfiguration.

Parameters:

config - the configuration to use for lookups (must not be null)

Throws:

IllegalArgumentException - if the configuration is null

Method Details

getConfiguration

public ImmutableConfiguration getConfiguration()

Gets the ImmutableConfiguration used by this object.

Returns:

the associated ImmutableConfiguration

lookup

public Object lookup(String variable)

Looks up the value of the specified variable. This method is called by ConfigurationInterpolator with the variable name extracted from the expression to interpolate (i.e. the prefix name has already been removed). A concrete implementation has to return the value of this variable or null if the variable name is unknown. This implementation calls getProperty() on the associated configuration. The return value is directly returned. Note that this may be a complex object, for example a collection or an array.

Specified by:

lookup in interface Lookup

Parameters:

variable - the name of the variable to be resolved

Returns:

the value of this variable or null