org.apache.fop.pdf
Class AbstractPDFStream

java.lang.Object
  org.apache.fop.pdf.PDFObject
      org.apache.fop.pdf.AbstractPDFStream

Direct Known 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 java.lang.String	buildStreamDict(java.lang.String lengthEntry) Constructs the dictionary for the stream.
protected int	encodeAndWriteStream(java.io.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(java.io.OutputStream stream) Overload the base object method so we don't have to copy byte arrays around so much
protected abstract void	outputRawStreamData(java.io.OutputStream out) Sends the raw stream data to the target OutputStream.
protected int	outputStreamData(StreamCache encodedStream, java.io.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, getDocument, getDocumentSafely, getGeneration, getObjectID, getObjectNumber, hasObjectNumber, referencePDF, setDocument, setObjectNumber, toPDF, toPDFString

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractPDFStream

public AbstractPDFStream()

Constructor for AbstractPDFStream.

Method Detail

setupFilterList

protected void setupFilterList()

Sets up the default filters for this stream if they haven't been set from outside.

getFilterList

public PDFFilterList getFilterList()

Returns the associated filter list.

Returns:

the filter list

getSizeHint

protected abstract int getSizeHint()
                            throws java.io.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)

Throws:

java.io.IOException - in case of an I/O problem

outputRawStreamData

protected abstract void outputRawStreamData(java.io.OutputStream out)
                                     throws java.io.IOException

Sends the raw stream data to the target OutputStream.

Parameters:

out - OutputStream to write to

Throws:

java.io.IOException - In case of an I/O problem

outputStreamData

protected int outputStreamData(StreamCache encodedStream,
                               java.io.OutputStream out)
                        throws java.io.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

Throws:

java.io.IOException - in case of an I/O problem

encodeStream

protected StreamCache encodeStream()
                            throws java.io.IOException

Encodes the raw data stream for output to a PDF file.

Returns:

the encoded stream

Throws:

java.io.IOException - in case of an I/O problem

encodeAndWriteStream

protected int encodeAndWriteStream(java.io.OutputStream out,
                                   PDFNumber refLength)
                            throws java.io.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)

Throws:

java.io.IOException - in case of an I/O problem

output

protected int output(java.io.OutputStream stream)
              throws java.io.IOException

Overload the base object method so we don't have to copy byte arrays around so much

Overrides:

output in class PDFObject

Parameters:

stream - the stream to write the PDF to

Returns:

the number of bytes written

Throws:

java.io.IOException - if there is an error writing to the stream

See Also:

PDFObject.output(OutputStream)

buildStreamDict

protected java.lang.String buildStreamDict(java.lang.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

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.