org.apache.fop.pdf

Class AbstractPDFStream

Implemented Interfaces:
PDFWritable
Known Direct Subclasses:
PDFStream, PDFT1Stream, PDFXObject

public abstract class AbstractPDFStream
extends PDFObject

This is an abstract base class for PDF streams.

Field Summary

Fields inherited from class org.apache.fop.pdf.PDFObject

DATE_FORMAT, log

Constructor Summary

AbstractPDFStream()
Constructor for AbstractPDFStream.

Method Summary

protected String
buildStreamDict(String lengthEntry)
Constructs the dictionary for the stream.
protected int
encodeAndWriteStream(OutputStream out, PDFNumber refLength)
Encodes and writes a stream directly to an OutputStream.
protected StreamCache
encodeStream()
Encodes the raw data stream for output to a PDF file.
PDFFilterList
getFilterList()
Returns the associated filter list.
protected abstract int
getSizeHint()
Returns a value that hints at the size of the encoded stream.
protected int
output(OutputStream stream)
Overload the base object method so we don't have to copy byte arrays around so much
protected abstract void
outputRawStreamData(OutputStream out)
Sends the raw stream data to the target OutputStream.
protected int
outputStreamData(StreamCache encodedStream, OutputStream out)
Output just the stream data enclosed by stream/endstream markers
protected void
prepareImplicitFilters()
Prepares implicit filters (such as the DCTFilter for JPEG images).
protected void
setupFilterList()
Sets up the default filters for this stream if they haven't been set from outside.

Methods inherited from class org.apache.fop.pdf.PDFObject

encode, encodeString, encodeText, formatDateTime, formatObject, getDocument, getDocumentSafely, getGeneration, getObjectID, getObjectNumber, hasObjectNumber, makeReference, output, referencePDF, setDocument, setObjectNumber, toInlinePDFString, toPDF, toPDFString

Constructor Details

AbstractPDFStream

public AbstractPDFStream()
Constructor for AbstractPDFStream.

Method Details

buildStreamDict

protected String buildStreamDict(String lengthEntry)
Constructs the dictionary for the stream. Override this method if you need additional entries.
Parameters:
lengthEntry - value for the /Length entry
Returns:
the newly constructed dictionary

encodeAndWriteStream

protected int encodeAndWriteStream(OutputStream out,
                                   PDFNumber refLength)
            throws IOException
Encodes and writes a stream directly to an OutputStream. The length of the stream, in this case, is set on a PDFNumber object that has to be prepared beforehand.
Parameters:
out - OutputStream to write to
refLength - PDFNumber object to receive the stream length
Returns:
number of bytes written (header and trailer included)

encodeStream

protected StreamCache encodeStream()
            throws IOException
Encodes the raw data stream for output to a PDF file.
Returns:
the encoded stream

getFilterList

public PDFFilterList getFilterList()
Returns the associated filter list.
Returns:
the filter list

getSizeHint

protected abstract int getSizeHint()
            throws IOException
Returns a value that hints at the size of the encoded stream. This is used to optimize buffer allocation so fewer buffer reallocations are necessary.
Returns:
an estimated size (0 if no hint can be given)

output

protected int output(OutputStream stream)
            throws IOException
Overload the base object method so we don't have to copy byte arrays around so much
Overrides:
output in interface PDFObject

outputRawStreamData

protected abstract void outputRawStreamData(OutputStream out)
            throws IOException
Sends the raw stream data to the target OutputStream.
Parameters:
out - OutputStream to write to

outputStreamData

protected int outputStreamData(StreamCache encodedStream,
                               OutputStream out)
            throws IOException
Output just the stream data enclosed by stream/endstream markers
Parameters:
encodedStream - already encoded/filtered stream to write
out - OutputStream to write to
Returns:
int number of bytes written

prepareImplicitFilters

protected void prepareImplicitFilters()
Prepares implicit filters (such as the DCTFilter for JPEG images). You must make sure that the appropriate filters are in the filter list at the right places.

setupFilterList

protected void setupFilterList()
Sets up the default filters for this stream if they haven't been set from outside.

Copyright 1999-2007 The Apache Software Foundation. All Rights Reserved.