org.apache.juneau.svl.vars.ManifestFileVar Maven / Gradle / Ivy
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package org.apache.juneau.svl.vars;
import org.apache.juneau.svl.*;
import org.apache.juneau.utils.*;
/**
* Manifest file entries variable resolver.
*
*
* The format for this var is "$MF{key[,default]}" .
*
*
* This variable resolver requires that a {@link ManifestFile} object be made available by calling
* the {@link #init(ManifestFile)} method.
*
*
Example:
*
* // Create a ManifestFile object that contains the manifest of the jar file containing this class.
* ManifestFile manifestFile = new ManifestFile(this .getClass());
*
* ManifestFileVar.init (manifestFile );
*
* // Create a variable resolver that resolves manifest file entries (e.g. "$MF{Main-Class}")
* VarResolver varResolver = VarResolver.create ().vars(ManifestFile.class ).build();
*
* // Use it!
* System.out .println(varResolver .resolve("The main class is $MF{Main-Class}" ));
*
*
*
* 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 ManifestFileVar extends DefaultingVar {
/** The name of this variable. */
public static final String NAME = "MF";
private static volatile ManifestFile MANIFEST_FILE;
/**
* Initialize the manifest file for this variable.
*
* @param manifestFile The parsed manifest file.
*/
public static void init(ManifestFile manifestFile) {
MANIFEST_FILE = manifestFile;
}
/**
* Constructor.
*/
public ManifestFileVar() {
super(NAME);
}
@Override /* Var */
public String resolve(VarResolverSession session, String key) {
return MANIFEST_FILE == null ? "" : MANIFEST_FILE.getString(key);
}
}