org.apache.juneau.config.vars.ConfigVar Maven / Gradle / Ivy
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package org.apache.juneau.config.vars;
import org.apache.juneau.config.*;
import org.apache.juneau.svl.*;
/**
* Config file variable resolver.
*
*
* The format for this var is "$C{key[,defaultValue]}" .
* See {@link Config#get(String)} for the format of the key.
*
*
* This variable resolver requires that a {@link Config} bean be available in the resolver session bean factory.
*
*
Example:
*
* // Create a config object.
* Config config = Config.create ().name("MyConfig.cfg" ).build();
*
* // Create a variable resolver that resolves config file entries (e.g. "$C{MySection/myKey}")
* VarResolver resolver = VarResolver
* .create ()
* .vars(ConfigVar.class )
* .bean(Config.class , config )
* .build();
*
* // Use it!
* System.out .println(resolver .resolve("Value for myKey in section MySection is $C{MySection/myKey}" ));
*
*
*
* Since this is a {@link SimpleVar}, any variables contained in the result will be recursively resolved.
* Likewise, if the arguments contain any variables, those will be resolved before they are passed to this var.
*
*
See Also:
*/
public class ConfigVar extends DefaultingVar {
/** The name of this variable. */
public static final String NAME = "C";
/**
* Constructor.
*/
public ConfigVar() {
super(NAME);
}
@Override /* Var */
public String resolve(VarResolverSession session, String key) {
return session.getBean(Config.class).get().get(key).orElse(null);
}
@Override /* Var */
public boolean canResolve(VarResolverSession session) {
return session.getBean(Config.class).isPresent();
}
}