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Class java.util.zip.Deflater 

java.lang.Object
   |
   +----java.util.zip.Deflater
public class Deflater
extends Object
This class provides support for general purpose decompression using the popular ZLIB compression library. The ZLIB compression library was initially developed as part of the PNG graphics standard and is not protected by patents. It is fully described in RFCs 1950, 1951, and 1952, which can be found at ftp://ds.internic.net/rfc in the files rfc1950.txt (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).

See Also:
Inflater

Variable Index

o BEST_COMPRESSION
Compression level for best compression.
o BEST_SPEED
Compression level for fastest compression.
o DEFAULT_COMPRESSION
Default compression level.
o DEFAULT_STRATEGY
Default compression strategy.
o DEFLATED
Compression method for the deflate algorithm (the only one currently supported).
o FILTERED
Compression strategy best used for data consisting mostly of small values with a somewhat random distribution.
o HUFFMAN_ONLY
Compression strategy for Huffman coding only.
o NO_COMPRESSION
Compression level for no compression.

Constructor Index

o Deflater()
Creates a new compressor with the default compression level.
o Deflater(int)
Creates a new compressor using the specified compression level.
o Deflater(int, boolean)
Creates a new compressor using the specified compression level.

Method Index

o deflate(byte[])
Fills specified buffer with compressed data.
o deflate(byte[], int, int)
Fills specified buffer with compressed data.
o end()
Discards unprocessed input and frees internal data.
o finalize()
Frees the compressor when garbage is collected.
o finish()
When called, indicates that compression should end with the current contents of the input buffer.
o finished()
Returns true if the end of the compressed data output stream has been reached.
o getAdler()
Returns the ADLER-32 value of the uncompressed data.
o getTotalIn()
Returns the total number of bytes input so far.
o getTotalOut()
Returns the total number of bytes output so far.
o needsInput()
Returns true if the input data buffer is empty and setInput() should be called in order to provide more input.
o reset()
Resets deflater so that a new set of input data can be processed.
o setDictionary(byte[])
Sets preset dictionary for compression.
o setDictionary(byte[], int, int)
Sets preset dictionary for compression.
o setInput(byte[])
Sets input data for compression.
o setInput(byte[], int, int)
Sets input data for compression.
o setLevel(int)
Sets the current compression level to the specified value.
o setStrategy(int)
Sets the compression strategy to the specified value.

Variables

o DEFLATED 
Properties Public Constant 
   DEFLATED=int
Compression method for the deflate algorithm (the only one currently supported).

o NO_COMPRESSION 
Properties Public Constant 
   NO_COMPRESSION=int
Compression level for no compression.

o BEST_SPEED 
Properties Public Constant 
   BEST_SPEED=int
Compression level for fastest compression.

o BEST_COMPRESSION 
Properties Public Constant 
   BEST_COMPRESSION=int
Compression level for best compression.

o DEFAULT_COMPRESSION 
Properties Public Constant 
   DEFAULT_COMPRESSION=int
Default compression level.

o FILTERED 
Properties Public Constant 
   FILTERED=int
Compression strategy best used for data consisting mostly of small values with a somewhat random distribution. Forces more Huffman coding and less string matching.

o HUFFMAN_ONLY 
Properties Public Constant 
   HUFFMAN_ONLY=int
Compression strategy for Huffman coding only.

o DEFAULT_STRATEGY 
Properties Public Constant 
   DEFAULT_STRATEGY=int
Default compression strategy.

Constructors

o Deflater 
    method Deflater(level=int, -
                    nowrap=boolean) public
Creates a new compressor using the specified compression level. If 'nowrap' is true then the ZLIB header and checksum fields will not be used in order to support the compression format used in both GZIP and PKZIP.

Parameters:
level - the compression level (0-9)
nowrap - if true then use GZIP compatible compression
o Deflater 
    method Deflater(level=int) public
Creates a new compressor using the specified compression level. Compressed data will be generated in ZLIB format.

Parameters:
level - the compression level (0-9)
o Deflater 
    method Deflater() public
Creates a new compressor with the default compression level. Compressed data will be generated in ZLIB format.

Methods

o setInput 
    method setInput(b=byte[], -
                    off=int, -
                    len=int)  public    protect
Sets input data for compression. This should be called whenever needsInput() returns true indicating that more input data is required.

Parameters:
b - the input data bytes
off - the start offset of the data
len - the length of the data
See Also:
needsInput
o setInput 
    method setInput(b=byte[])  public
Sets input data for compression. This should be called whenever needsInput() returns true indicating that more input data is required.

Parameters:
b - the input data bytes
See Also:
needsInput
o setDictionary 
    method setDictionary(b=byte[], -
                         off=int, -
                         len=int)  public    protect
Sets preset dictionary for compression. A preset dictionary is used when the history buffer can be predetermined. When the data is later uncompressed with Inflater.inflate(), Inflater.getAdler() can be called in order to get the Adler-32 value of the dictionary required for decompression.

Parameters:
b - the dictionary data bytes
off - the start offset of the data
len - the length of the data
See Also:
inflate, getAdler
o setDictionary 
    method setDictionary(b=byte[])  public
Sets preset dictionary for compression. A preset dictionary is used when the history buffer can be predetermined. When the data is later uncompressed with Inflater.inflate(), Inflater.getAdler() can be called in order to get the Adler-32 value of the dictionary required for decompression.

Parameters:
b - the dictionary data bytes
See Also:
inflate, getAdler
o setStrategy 
    method setStrategy(strategy=int)  public    protect
Sets the compression strategy to the specified value.

Parameters:
strategy - the new compression strategy
Throws: IllegalArgumentException
if the compression strategy is invalid
o setLevel 
    method setLevel(Level=int)  public    protect
Sets the current compression level to the specified value.

Parameters:
level - the new compression level (0-9)
Throws: IllegalArgumentException
if the compression level is invalid
o needsInput 
    method needsInput() returns boolean public
Returns true if the input data buffer is empty and setInput() should be called in order to provide more input.

o finish 
    method finish()  public    protect
When called, indicates that compression should end with the current contents of the input buffer.

o finished 
    method finished() returns boolean public    protect
Returns true if the end of the compressed data output stream has been reached.

o deflate 
    method deflate(b=byte[], -
                   off=int, -
                   len=int) returns int public    protect
Fills specified buffer with compressed data. Returns actual number of bytes of compressed data. A return value of 0 indicates that needsInput() should be called in order to determine if more input data is required.

Parameters:
b - the buffer for the compressed data
off - the start offset of the data
len - the maximum number of bytes of compressed data
Returns:
the actual number of bytes of compressed data
o deflate 
    method deflate(b=byte[]) returns int public
Fills specified buffer with compressed data. Returns actual number of bytes of compressed data. A return value of 0 indicates that needsInput() should be called in order to determine if more input data is required.

Parameters:
b - the buffer for the compressed data
Returns:
the actual number of bytes of compressed data
o getAdler 
    method getAdler() returns int public    protect
Returns the ADLER-32 value of the uncompressed data.

o getTotalIn 
    method getTotalIn() returns int public    protect
Returns the total number of bytes input so far.

o getTotalOut 
    method getTotalOut() returns int public    protect
Returns the total number of bytes output so far.

o reset 
    method reset()  public    protect
Resets deflater so that a new set of input data can be processed. Keeps current compression level and strategy settings.

o end 
    method end()  public    protect
Discards unprocessed input and frees internal data.

o finalize 
    method finalize()  Inheritable
Frees the compressor when garbage is collected.

Overrides:
finalize in class Object 
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