net.talvi.puffinplot

Class JythonJarManager

java.lang.Object

net.talvi.puffinplot.JythonJarManager

public class JythonJarManager
extends java.lang.Object

A collection of static methods for managing the Jython jar.

PuffinPlot can make use of Jython, but for reasons of size Jython is not included in the build. To use Jython in PuffinPlot, the Jython jar must be downloaded and installed locally. This class provides some static utility methods to check for a local Jython jar, verify its integrity, download it from a known URL, or delete it from the local cache.

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	SOURCE_URL_STRING A string representation of the URL from which the jython jar is downloaded.

Constructor Summary

Constructors

Constructor and Description
JythonJarManager()

Method Summary

Modifier and Type	Method and Description
static boolean	checkInstalled(boolean deleteIfWrongSize) Checks whether the Jython jar file is installed locally and has the correct size.
static boolean	checkSha1Digest(boolean deleteIfIncorrect) Calculates the SHA-1 digest of the Jython jar file and verifies it against a hard-coded reference value.
static void	download() Downloads the Jython jar from a hard-coded URL and saves it in the application data directory.
static long	getExpectedDownloadSize()
static java.nio.file.Path	getPath() Returns the local path for the Jython jar file with the application data directory.

Methods inherited from class java.lang.Object

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

Field Detail

SOURCE_URL_STRING

public static final java.lang.String SOURCE_URL_STRING

A string representation of the URL from which the jython jar is downloaded.

See Also:

Constant Field Values

Constructor Detail

JythonJarManager

public JythonJarManager()

Method Detail

getPath

public static java.nio.file.Path getPath()
                                  throws java.io.IOException

Returns the local path for the Jython jar file with the application data directory. The method does not guarantee that the jar is currently present at this location.

Returns:

the local path to the jython jar file

Throws:

java.io.IOException - if there was an error determining the path

checkSha1Digest

public static boolean checkSha1Digest(boolean deleteIfIncorrect)
                               throws java.io.IOException,
                                      java.security.NoSuchAlgorithmException

Calculates the SHA-1 digest of the Jython jar file and verifies it against a hard-coded reference value.

Parameters:

deleteIfIncorrect - If this parameter is true, and if the SHA-1 digest is not correct, the jar file will be deleted

Returns:

true iff the Jython jar file has the correct SHA-1 digest

Throws:

java.io.IOException - if there was an error reading the jar file

java.security.NoSuchAlgorithmException - if the SHA-1 algorithm was not available

checkInstalled

public static boolean checkInstalled(boolean deleteIfWrongSize)
                              throws java.io.IOException

Checks whether the Jython jar file is installed locally and has the correct size. The size is checked against a known, hard-coded value. This method does not check the SHA-1 digest.

Parameters:

deleteIfWrongSize - if true, and if the jar file does not have the correct size, it will be deleted.

Returns:

true iff the Jython jar file is locally installed and has the correct size

Throws:

java.io.IOException - if there was an error checking or deleting the jar file

download

public static void download()
                     throws java.io.IOException

Downloads the Jython jar from a hard-coded URL and saves it in the application data directory.

This method may block indefinitely.

Throws:

java.io.IOException - if there is an error reading from the URL or writing to the file

getExpectedDownloadSize

public static long getExpectedDownloadSize()

Returns:

The expected size, in bytes, of the Jython jar.