/**
* Read the version information from a file with a given file name. The file must be a jar
* manifest file and all its entries are searched for package names and their specification
* version information. All information is collected in a map for later lookup of package names
* and their versions.
*
* @param versionFileName name of the jar file containing version information
*/
public static String readVersionFromFile(String applicationName, String versionFileName) {
try {
FileInputStream fileInput = new FileInputStream(versionFileName);
Manifest manifest = new Manifest();
manifest.read(fileInput);
Map entries = manifest.getEntries();
// Now write out the pre-entry attributes
Iterator entryIterator = entries.entrySet().iterator();
while (entryIterator.hasNext()) {
Map.Entry currentEntry = (Map.Entry) entryIterator.next();
String packageName = currentEntry.getKey().toString();
packageName = normalizePackageName(packageName);
Attributes attributes = (Attributes) currentEntry.getValue();
String packageSpecVersion = attributes.getValue(Attributes.Name.SPECIFICATION_VERSION);
packageSpecVersion = extractVersionInfo(packageSpecVersion);
return packageSpecVersion;
}
} catch (IOException exception) {
exception.printStackTrace();
}
// no version found
return null;
}
