org.foray.pdf.object
Class PDFStream

java.lang.Object
  org.foray.pdf.object.PDFObject
      org.foray.pdf.object.PDFStream

Direct Known Subclasses:

PDFCMap, PDFContentStream, PDFEmbeddedFileStream, PDFFontFileStream, PDFICCStream, PDFXObject

public abstract class PDFStream
extends PDFObject

Superclass for all PDF stream objects. A PDF Stream has two parts: a dictionary, and the stream itself. The stream of commands is where the real work is done, the dictionary just provides information like the stream length.

See Also:

"PDF Reference, 3rd Edition, Section 3.2.7."

Field Summary

Fields inherited from class org.foray.pdf.object.PDFObject

EOL, MSG_EOL, XREF_EOL

Constructor Summary

PDFStream(PDFDocument doc)
Constructor.

Method Summary

void	add(String s) Append data to the stream.
void	addDefaultFilters() Adds the default filter to this stream.
void	addEncryption(PDFEncryption encryption) Add the encryption filter.
void	addFilter(org.axsl.ps.PsEncodeFilter filter) Add a filter for compression of the stream.
org.axsl.ps.PsEncodeFilter	addFilter(String filterType) Adds a filter of the specified type to this stream.
protected String	applyFilters() Apply the filters to the data in the order given.
protected abstract void	finalizeStreamContent() This method is an explicit opportunity for subclasses to finish writing whatever content may still need to be written to the stream before the dictionary and stream contents are written.
int	getDataLength() Returns the number of bytes written to this stream.
protected OutputStream	getOutputStream() Returns the output stream.
protected int	output(OutputStream stream) Write the PDF represention of this object to a given output stream.
protected int	outputStreamData(OutputStream stream) Output just the stream data enclosed by stream/endstream markers.
void	setData(byte[] data) Writes some data to this stream.
protected void	setOutputStream(OutputStream outputStream) Sets the output stream.
protected abstract String	specialStreamDictEntries() Subclasses return any specialized dictionary entries here, so that they are included when writing the stream dictionary.
String	toPDF() Generates the PDF text necessary to represent the object, returning it as a String.

Methods inherited from class org.foray.pdf.object.PDFObject

bufferToByteArray, byteArrayToStream, getCharsPerLine, getGeneration, getLogger, getNumber, getPDFDocument, pdfID, pdfReference, setNumber, stringToByteArray

Methods inherited from class java.lang.Object

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

Constructor Detail

PDFStream

public PDFStream(PDFDocument doc)

Constructor. Creates an empty stream object.

Parameters:

doc - The PDFDocument to which this stream is attached.

Method Detail

add

public void add(String s)
         throws org.axsl.pdf.PdfException

Append data to the stream.

Parameters:

s - The string of PDF to add.

Throws:

org.axsl.pdf.PdfException - For errors writing to output.

addFilter

public void addFilter(org.axsl.ps.PsEncodeFilter filter)
               throws org.axsl.pdf.PdfException

Add a filter for compression of the stream. Note that the filters should be added in reverse order, that is the last filter to be applied should be added first. The filter addes should always be a new instance of that filter class. The applied flag in the filter is marked true after it has been applied to the data.

Parameters:

filter - The filter to be added.

Throws:

org.axsl.pdf.PdfException - For errors adding the filter.

addEncryption

public void addEncryption(PDFEncryption encryption)

Add the encryption filter.

Parameters:

encryption - The encryption filter to add.

addFilter

public org.axsl.ps.PsEncodeFilter addFilter(String filterType)
                                     throws org.axsl.pdf.PdfException

Adds a filter of the specified type to this stream. Note that the filters should be added in reverse order, that is the last filter to be applied should be added first.

Parameters:

filterType - The type of filter to add, one of "flate", "ascii-85", or "ascii-hex".

Returns:

The newly-created filter.

Throws:

org.axsl.pdf.PdfException - For errors while adding the filter.

addDefaultFilters

public void addDefaultFilters()
                       throws org.axsl.pdf.PdfException

Adds the default filter to this stream.

Throws:

org.axsl.pdf.PdfException - For errors while adding the filters.

setData

public void setData(byte[] data)
             throws org.axsl.pdf.PdfException

Writes some data to this stream.

Parameters:

data - The data to be written.

Throws:

org.axsl.pdf.PdfException - For errors when writing.

getDataLength

public int getDataLength()

Returns the number of bytes written to this stream.

Returns:

The number of bytes written to this stream.

toPDF

public String toPDF()

Description copied from class: PDFObject

Generates the PDF text necessary to represent the object, returning it as a String.

Returns:

The PDF text necessary to represent the object.

output

protected int output(OutputStream stream)
              throws org.axsl.pdf.PdfException

Description copied from class: PDFObject

Write the PDF represention of this object to a given output stream.

Overrides:

output in class PDFObject

Parameters:

stream - The stream to which the PDF content is being written.

Returns:

The number of bytes written.

Throws:

org.axsl.pdf.PdfException - For I/O errors during output.

finalizeStreamContent

protected abstract void finalizeStreamContent()
                                       throws org.axsl.pdf.PdfException

This method is an explicit opportunity for subclasses to finish writing whatever content may still need to be written to the stream before the dictionary and stream contents are written.

Throws:

org.axsl.pdf.PdfException - For errors writing stream content.

specialStreamDictEntries

protected abstract String specialStreamDictEntries()
                                            throws org.axsl.pdf.PdfException

Subclasses return any specialized dictionary entries here, so that they are included when writing the stream dictionary.

Returns:

Any specialized dictionary entries.

Throws:

org.axsl.pdf.PdfException - For errors creating the dictionary entries.

outputStreamData

protected int outputStreamData(OutputStream stream)
                        throws org.axsl.pdf.PdfException

Output just the stream data enclosed by stream/endstream markers.

Parameters:

stream - The stream to which the data should be written.

Returns:

The number of bytes written.

Throws:

org.axsl.pdf.PdfException - For errors during writing.

applyFilters

protected String applyFilters()

Apply the filters to the data in the order given.

Returns:

The /Filter and /DecodeParms entries for the stream dictionary.

getOutputStream

protected OutputStream getOutputStream()

Returns the output stream.

Returns:

The output stream.

setOutputStream

protected void setOutputStream(OutputStream outputStream)

Sets the output stream.

Parameters:

outputStream - The new output stream.