jpos.loader.Version Maven / Gradle / Ivy
package jpos.loader;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.jar.Attributes;
import java.util.jar.Manifest;
///////////////////////////////////////////////////////////////////////////////
//
// This software is provided "AS IS". The JavaPOS working group (including
// each of the Corporate members, contributors and individuals) MAKES NO
// REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF THE SOFTWARE,
// EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED
// WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NON-INFRINGEMENT. The JavaPOS working group shall not be liable for
// any damages suffered as a result of using, modifying or distributing this
// software or its derivatives. Permission to use, copy, modify, and distribute
// the software and its documentation for any purpose is hereby granted.
//
// The JavaPOS Config/Loader (aka JCL) is now under the CPL license, which
// is an OSS Apache-like license. The complete license is located at:
// http://www.ibm.com/developerworks/library/os-cpl.html
//
///////////////////////////////////////////////////////////////////////////////
/**
* Simple Version class indicating that prints out the curent version of the JCL
* @since 1.2 (NY 2K meeting)
* @author E. Michael Maximilien ([email protected])
*/
public final class Version extends Object
{
/**
* Main entry point for the Version application
* @param args a String[] of arguments
* @since 1.2 (NY 2K meeting)
*/
public static void main( String[] args )
{
System.out.println( "JavaPOS jpos.config/loader (JCL) version " +
JCL_VERSION_STRING );
}
/**
* @return a String of the version number of the JCL
* @since 1.2 (NY 2K meeting)
*/
public static String getVersionString() { return JCL_VERSION_STRING; }
//--------------------------------------------------------------------------
// Class variables
//
private static final String JCL_VERSION_STRING = getImplementationVersion();
final private static String getImplementationVersion()
{
try
{
// Retrieve the corresponding manifest file of the calling class
String classContainer = Version.class.getProtectionDomain().getCodeSource().getLocation().toString();
Manifest manifest = readManifest(classContainer);
// Retrieve all the custom entries included in the manifest file
Attributes.Name keyName = new Attributes.Name("Implementation-Version");
Attributes mainAttributes = manifest.getMainAttributes();
if (mainAttributes == null || !mainAttributes.containsKey(keyName)) {
return "version_determination_failed";
}
return mainAttributes.getValue(keyName);
}
catch (Exception e)
{
return "version_determination_failed";
}
}
private static Manifest readManifest(String classContainer) throws IOException {
URL manifestUrl = new URL("jar:" + classContainer + "!/META-INF/MANIFEST.MF");
InputStream manifestIn;
try {
manifestIn = manifestUrl.openStream();
}
catch (IOException ioe) {
// try from file for testing and development environments
try {
manifestIn = new URL(classContainer + "/META-INF/MANIFEST.MF").openStream();
}
catch (IOException ioeForFileAccess) {
throw ioe;
}
}
try {
return new Manifest(manifestIn);
}
finally {
try { manifestIn.close(); } catch (IOException ioe) {} // ignore exception
}
}
}
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