Package org.apache.commons.compress.harmony.unpack200

Class Segment

java.lang.Object

org.apache.commons.compress.harmony.unpack200.Segment

public class Segment
extends Object

A Pack200 archive consists of one or more segments. Each segment is stand-alone, in the sense that every segment has the magic number header; thus, every segment is also a valid archive. However, it is possible to combine (non-GZipped) archives into a single large archive by concatenation alone. Thus, all the hard work in unpacking an archive falls to understanding a segment. The first component of a segment is the header; this contains (amongst other things) the expected counts of constant pool entries, which in turn defines how many values need to be read from the stream. Because values are variable width (see Codec), it is not possible to calculate the start of the next segment, although one of the header values does hint at the size of the segment if non-zero, which can be used for buffering purposes. Note that this does not perform any buffering of the input stream; each value will be read on a byte-by-byte basis. It does not perform GZip decompression automatically; both of these are expected to be done by the caller if the stream has the magic header for GZip streams (GZIPInputStream.GZIP_MAGIC). In any case, if GZip decompression is being performed the input stream will be buffered at a higher level, and thus this can read on a byte-oriented basis.

Field Summary

Fields

Modifier and Type	Field	Description
static final int	LOG_LEVEL_QUIET
static final int	LOG_LEVEL_STANDARD
static final int	LOG_LEVEL_VERBOSE

Constructor Summary

Constructors

Constructor	Description
Segment()

Method Summary

Modifier and Type	Method	Description
protected AttrDefinitionBands	getAttrDefinitionBands()
protected ClassBands	getClassBands()
SegmentConstantPool	getConstantPool()
protected CpBands	getCpBands()
protected IcBands	getIcBands()
SegmentHeader	getSegmentHeader()
void	log(int logLevel, String message)
void	overrideDeflateHint(boolean deflateHint)	Override the archive's deflate hint with the given boolean
void	setLogLevel(int logLevel)
void	setLogStream(OutputStream logStream)
void	setPreRead(boolean value)
void	unpack(InputStream inputStream, JarOutputStream out)	Unpacks a packed stream (either .pack.
void	writeJar(JarOutputStream out)	Writes the segment to an output stream.

Methods inherited from class java.lang.Object

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

Field Details

LOG_LEVEL_VERBOSE

public static final int LOG_LEVEL_VERBOSE

See Also:

• Constant Field Values

LOG_LEVEL_STANDARD

public static final int LOG_LEVEL_STANDARD

See Also:

• Constant Field Values

LOG_LEVEL_QUIET

public static final int LOG_LEVEL_QUIET

See Also:

• Constant Field Values

Constructor Details

Segment

public Segment()

Method Details

getAttrDefinitionBands

protected AttrDefinitionBands getAttrDefinitionBands()

getClassBands

protected ClassBands getClassBands()

getConstantPool

public SegmentConstantPool getConstantPool()

getCpBands

protected CpBands getCpBands()

getIcBands

protected IcBands getIcBands()

getSegmentHeader

public SegmentHeader getSegmentHeader()

log

public void log(int logLevel,
 String message)

overrideDeflateHint

public void overrideDeflateHint(boolean deflateHint)

Override the archive's deflate hint with the given boolean

Parameters:

deflateHint - - the deflate hint to use

setLogLevel

public void setLogLevel(int logLevel)

setLogStream

public void setLogStream(OutputStream logStream)

setPreRead

public void setPreRead(boolean value)

unpack

public void unpack(InputStream inputStream,
 JarOutputStream out)
            throws IOException,
Pack200Exception

Unpacks a packed stream (either .pack. or .pack.gz) into a corresponding JarOuputStream.

Parameters:

inputStream - a packed input stream, preferably a BoundedInputStream.

out - output stream.

Throws:

Pack200Exception - if there is a problem unpacking

IOException - if there is a problem with I/O during unpacking

writeJar

public void writeJar(JarOutputStream out)
              throws IOException

Writes the segment to an output stream. The output stream should be pre-buffered for efficiency. Also takes the same input stream for reading, since the file bits may not be loaded and thus just copied from one stream to another. Doesn't close the output stream when finished, in case there are more entries (e.g. further segments) to be written.

Parameters:

out - the JarOutputStream to write data to

Throws:

IOException - if an error occurs while reading or writing to the streams