org.apache.pdfbox.filter

Class Filter

java.lang.Object

org.apache.pdfbox.filter.Filter

Direct Known Subclasses:

JPXFilter, LZWFilter

public abstract class Filter
extends Object

A filter for stream data.

Author:

Ben Litchfield, John Hewson

Field Summary

Fields

Modifier and Type	Field and Description
static String	SYSPROP_DEFLATELEVEL Compression Level System Property.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Filter() Constructor.

Method Summary

Modifier and Type	Method and Description
abstract DecodeResult	decode(InputStream encoded, OutputStream decoded, COSDictionary parameters, int index) Decodes data, producing the original non-encoded data.
DecodeResult	decode(InputStream encoded, OutputStream decoded, COSDictionary parameters, int index, DecodeOptions options) Decodes data, with optional DecodeOptions.
protected abstract void	encode(InputStream input, OutputStream encoded, COSDictionary parameters)
void	encode(InputStream input, OutputStream encoded, COSDictionary parameters, int index) Encodes data.
protected static ImageReader	findImageReader(String formatName, String errorCause) Finds a suitable image reader for a format.
static int	getCompressionLevel()
protected COSDictionary	getDecodeParams(COSDictionary dictionary, int index)

Methods inherited from class java.lang.Object

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

Field Detail

SYSPROP_DEFLATELEVEL

public static final String SYSPROP_DEFLATELEVEL

Compression Level System Property. Set this to a value from 0 to 9 to change the zlib deflate compression level used to compress /Flate streams. The default value is -1 which is Deflater.DEFAULT_COMPRESSION. To set maximum compression, use System.setProperty(Filter.SYSPROP_DEFLATELEVEL, "9");

See Also:

Constant Field Values

Constructor Detail

Filter

protected Filter()

Constructor.

Method Detail

decode

public abstract DecodeResult decode(InputStream encoded,
                                    OutputStream decoded,
                                    COSDictionary parameters,
                                    int index)
                             throws IOException

Decodes data, producing the original non-encoded data.

Parameters:

encoded - the encoded byte stream

decoded - the stream where decoded data will be written

parameters - the parameters used for decoding

index - the index to the filter being decoded

Returns:

repaired parameters dictionary, or the original parameters dictionary

Throws:

IOException - if the stream cannot be decoded

decode

public DecodeResult decode(InputStream encoded,
                           OutputStream decoded,
                           COSDictionary parameters,
                           int index,
                           DecodeOptions options)
                    throws IOException

Decodes data, with optional DecodeOptions. Not all filters support all options, and so callers should check the options' honored flag to test if they were applied.

Parameters:

encoded - the encoded byte stream

decoded - the stream where decoded data will be written

parameters - the parameters used for decoding

index - the index to the filter being decoded

options - additional options for decoding

Returns:

repaired parameters dictionary, or the original parameters dictionary

Throws:

IOException - if the stream cannot be decoded

encode

public final void encode(InputStream input,
                         OutputStream encoded,
                         COSDictionary parameters,
                         int index)
                  throws IOException

Encodes data.

Parameters:

input - the byte stream to encode

encoded - the stream where encoded data will be written

parameters - the parameters used for encoding

index - the index to the filter being encoded

Throws:

IOException - if the stream cannot be encoded

encode

protected abstract void encode(InputStream input,
                               OutputStream encoded,
                               COSDictionary parameters)
                        throws IOException

Throws:

IOException

getDecodeParams

protected COSDictionary getDecodeParams(COSDictionary dictionary,
                                        int index)

findImageReader

protected static ImageReader findImageReader(String formatName,
                                             String errorCause)
                                      throws MissingImageReaderException

Finds a suitable image reader for a format.

Parameters:

formatName - The format to search for.

errorCause - The probably cause if something goes wrong.

Returns:

The image reader for the format.

Throws:

MissingImageReaderException - if no image reader is found.

getCompressionLevel

public static int getCompressionLevel()

Returns:

the ZIP compression level configured for PDFBox