public abstract class Pack200
extends Object 

 import java.util.jar.Pack200;
 import java.util.jar.Pack200.*;
 ...
 // Create the Packer object
 Packer packer = Pack200.newPacker();
 // Initialize the state by setting the desired properties
 Map p = packer.properties();
 // take more time choosing codings for better compression
 p.put(Packer.EFFORT, "7"); // default is "5"
 // use largest-possible archive segments (>10% better compression).
 p.put(Packer.SEGMENT_LIMIT, "-1");
 // reorder files for better compression.
 p.put(Packer.KEEP_FILE_ORDER, Packer.FALSE);
 // smear modification times to a single value.
 p.put(Packer.MODIFICATION_TIME, Packer.LATEST);
 // ignore all JAR deflation requests,
 // transmitting a single request to use "store" mode.
 p.put(Packer.DEFLATE_HINT, Packer.FALSE);
 // discard debug attributes
 p.put(Packer.CODE_ATTRIBUTE_PFX+"LineNumberTable", Packer.STRIP);
 // throw an error if an attribute is unrecognized
 p.put(Packer.UNKNOWN_ATTRIBUTE, Packer.ERROR);
 // pass one class file uncompressed:
 p.put(Packer.PASS_FILE_PFX+0, "mutants/Rogue.class");
 try {
 JarFile jarFile = new JarFile("/tmp/testref.jar");
 FileOutputStream fos = new FileOutputStream("/tmp/test.pack");
 // Call the packer
 packer.pack(jarFile, fos);
 jarFile.close();
 fos.close();
 File f = new File("/tmp/test.pack");
 FileOutputStream fostream = new FileOutputStream("/tmp/test.jar");
 JarOutputStream jostream = new JarOutputStream(fostream);
 Unpacker unpacker = Pack200.newUnpacker();
 // Call the unpacker
 unpacker.unpack(f, jostream);
 // Must explicitly close the output.
 jostream.close();
 } catch (IOException ioe) {
 ioe.printStackTrace();
 }
 

Since:

1.5

• Nested Class Summary

  Nested Classes

  Modifier and Type	Class	Description
  static interface	Pack200.Packer	The packer engine applies various transformations to the input JAR file, making the pack stream highly compressible by a compressor such as gzip or zip.
  static interface	Pack200.Unpacker	The unpacker engine converts the packed stream to a JAR file.

• Method Summary

  All Methods

  Modifier and Type	Method	Description
  static Pack200.Packer	newPacker ()	Obtain new instance of a class that implements Packer.
  static Pack200.Unpacker	newUnpacker ()	Obtain new instance of a class that implements Unpacker.

  • Methods inherited from class java.lang.Object

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

• Method Detail

  • newPacker

    public static Pack200.Packer newPacker()

    Obtain new instance of a class that implements Packer.

    • If the system property java.util.jar.Pack200.Packer is defined, then the value is taken to be the fully-qualified name of a concrete implementation class, which must implement Packer. This class is loaded and instantiated. If this process fails then an unspecified error is thrown.

    • If an implementation has not been specified with the system property, then the system-default implementation class is instantiated, and the result is returned.

    Note: The returned object is not guaranteed to operate correctly if multiple threads use it at the same time. A multi-threaded application should either allocate multiple packer engines, or else serialize use of one engine with a lock.

    Returns:

    A newly allocated Packer engine.

  • newUnpacker

    public static Pack200.Unpacker newUnpacker()

    Obtain new instance of a class that implements Unpacker.

    • If the system property java.util.jar.Pack200.Unpacker is defined, then the value is taken to be the fully-qualified name of a concrete implementation class, which must implement Unpacker. The class is loaded and instantiated. If this process fails then an unspecified error is thrown.

    • If an implementation has not been specified with the system property, then the system-default implementation class is instantiated, and the result is returned.

    Note: The returned object is not guaranteed to operate correctly if multiple threads use it at the same time. A multi-threaded application should either allocate multiple unpacker engines, or else serialize use of one engine with a lock.

    Returns:

    A newly allocated Unpacker engine.