Module java.base
Package java.util.jar

Interface Pack200.Unpacker

  • Enclosing class:
    Pack200

    public static interface Pack200.Unpacker
    The unpacker engine converts the packed stream to a JAR file. An instance of the engine can be obtained using Pack200.newUnpacker().

    Every JAR file produced by this engine will include the string "PACK200" as a zip file comment. This allows a deployer to detect if a JAR archive was packed and unpacked.

    Note: Unless otherwise noted, passing a null argument to a constructor or method in this class will cause a NullPointerException to be thrown.

    This version of the unpacker is compatible with all previous versions.

    Since:
    1.5
    • Field Summary

      Fields 
      Modifier and Type Field Description
      static String DEFLATE_HINT
      Property indicating that the unpacker should ignore all transmitted values for DEFLATE_HINT, replacing them by the given value, TRUE or FALSE.
      static String FALSE
      The string "false", a possible value for certain properties.
      static String KEEP
      The string "keep", a possible value for certain properties.
      static String PROGRESS
      The unpacker's progress as a percentage, as periodically updated by the unpacker.
      static String TRUE
      The string "true", a possible value for certain properties.
    • Field Detail

      • DEFLATE_HINT

        static final String DEFLATE_HINT
        Property indicating that the unpacker should ignore all transmitted values for DEFLATE_HINT, replacing them by the given value, TRUE or FALSE. The default value is the special string KEEP, which asks the unpacker to preserve all transmitted deflation hints.
        See Also:
        Constant Field Values
      • PROGRESS

        static final String PROGRESS
        The unpacker's progress as a percentage, as periodically updated by the unpacker. Values of 0 - 100 are normal, and -1 indicates a stall. Progress can be monitored by polling the value of this property.

        At a minimum, the unpacker must set progress to 0 at the beginning of an unpacking operation, and to 100 at the end.

        See Also:
        Constant Field Values
    • Method Detail

      • properties

        SortedMap<String,String> properties()
        Get the set of this engine's properties. This set is a "live view", so that changing its contents immediately affects the Unpacker engine, and changes from the engine (such as progress indications) are immediately visible in the map.

        The property map may contain pre-defined implementation specific and default properties. Users are encouraged to read the information and fully understand the implications, before modifying pre-existing properties.

        Implementation specific properties are prefixed with a package name associated with the implementor, beginning with com. or a similar prefix. All property names beginning with pack. and unpack. are reserved for use by this API.

        Unknown properties may be ignored or rejected with an unspecified error, and invalid entries may cause an unspecified error to be thrown.

        Returns:
        A sorted association of option key strings to option values.
      • unpack

        void unpack​(InputStream in,
                    JarOutputStream out)
             throws IOException
        Read a Pack200 archive, and write the encoded JAR to a JarOutputStream. The entire contents of the input stream will be read. It may be more efficient to read the Pack200 archive to a file and pass the File object, using the alternate method described below.

        Closes its input but not its output. (The output can accumulate more elements.)

        Parameters:
        in - an InputStream.
        out - a JarOutputStream.
        Throws:
        IOException - if an error is encountered.
      • unpack

        void unpack​(File in,
                    JarOutputStream out)
             throws IOException
        Read a Pack200 archive, and write the encoded JAR to a JarOutputStream.

        Does not close its output. (The output can accumulate more elements.)

        Parameters:
        in - a File.
        out - a JarOutputStream.
        Throws:
        IOException - if an error is encountered.