Package org.jvnet.hk2.config

Class VariableResolver

java.lang.Object

org.jvnet.hk2.config.VariableResolver

All Implemented Interfaces:

Translator

Direct Known Subclasses:

AttributeResolverHelper

public abstract class VariableResolver
extends Object
implements Translator

Translator that does variable resolution in the Ant style.

This implementation looks for variables in the string like "${xyz}" or "${abc.DEF.ghi}". The getVariableValue(String) method is then used to obtain the actual value for the variable.

"$$" works as the escape of "$", so for example "$${abc}" expands to "${abc}" where "${abc}" would have expanded to "value-of-abc". A lone "$" is left as-is, so "$abc" expands to "$abc".

Author:

Kohsuke Kawaguchi

Field Summary

Fields inherited from interface org.jvnet.hk2.config.Translator

NOOP, SYS_PROP_TR

Constructor Summary

Constructors

Constructor	Description
VariableResolver()

Method Summary

Modifier and Type	Method	Description
protected abstract String	getVariableValue(String varName)	Returns the value of the variable.
String	translate(String str)

Methods inherited from class java.lang.Object

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

Constructor Detail

VariableResolver

public VariableResolver()

Method Detail

translate

public String translate(String str)
                 throws TranslationException

Specified by:

translate in interface Translator

Throws:

TranslationException

getVariableValue

protected abstract String getVariableValue(String varName)
                                    throws TranslationException

Returns the value of the variable. This class will not try to further expand variables in the returned value. If the implementation wants to do so, that is the implementation's responsibility.

Returns:

null if the variable is not found. The caller will report an error. When the variable is not found, it's also legal to throw TranslationException, which is an useful technique if the implementation would like to report additional errors.

Throws:

TranslationException