gnu.apdf

Class PDFStream

java.lang.Object

gnu.apdf.PDFObject

gnu.apdf.PDFStream

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

PDFImage, PDFPattern, PDFShading

public class PDFStream
extends PDFObject
implements Serializable

This class implements a PDF stream object. In PDF, streams contain data like the graphic operators that render a page, or the pixels of an image.

In PDF, a stream can be compressed using several different methods, or left uncompressed. Here we support both uncompressed and FlateDecode.

Author:

Peter T Mount http://www.retep.org.uk/pdf/, Eric Z. Beard, ericzbeard@hotmail.com, Jon Sevy, jsevy@cs.drexel.edu

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
PDFStream() Constructs a plain stream.
PDFStream(String type) Constructs a stream.

Method Summary

Modifier and Type	Method and Description
boolean	getDeflate() Returs true if the stream will be compressed.
OutputStream	getOutputStream() Returns the OutputStream that will append to this stream.
ByteArrayOutputStream	getStream() This is for extenders, and provides access to the stream.
String	getStreamDataString() Used for printing stream contents in human-readable form, for debugging.
PrintWriter	getWriter() Creates a PrintWriter that will append to this stream.
void	setDeflate(boolean mode)
void	write(OutputStream os) Writes the object to the output stream.
void	writeStream(OutputStream os) This inserts the Streams length, then the actual stream, finally the end of stream/object markers.

Methods inherited from class gnu.apdf.PDFObject

getGeneration, getName, getPDFDocument, getSerialID, getType, setName, toArray, toString, writeEnd, writeStart

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

PDFStream

public PDFStream()

Constructs a plain stream.

By default, the stream will be compressed.

PDFStream

public PDFStream(String type)

Constructs a stream. The supplied type is stored in the stream's header and is used by other objects that extend the PDFStream class (like PDFImage).

By default, the stream will be compressed.

Parameters:

type - type for the stream

See Also:

PDFImage

Method Detail

setDeflate

public void setDeflate(boolean mode)

Parameters:

mode - true will FlatDecode the stream

getDeflate

public boolean getDeflate()

Returs true if the stream will be compressed.

Returns:

true if compression is enabled

getOutputStream

public OutputStream getOutputStream()

Returns the OutputStream that will append to this stream.

Returns:

The stream for this object

getWriter

public PrintWriter getWriter()

Creates a PrintWriter that will append to this stream.

Returns:

a PrintWriter to write to the stream

getStream

public ByteArrayOutputStream getStream()

This is for extenders, and provides access to the stream.

Returns:

ByteArrayOutputStream containing the contents.

write

public void write(OutputStream os)
           throws IOException

Description copied from class: PDFObject

Writes the object to the output stream. This method must be overidden.

Note: It should not write any other objects, even if they are it's Kids, as they will be written by the calling routine.

Specified by:

write in class PDFObject

Parameters:

os - OutputStream to send the object to

Throws:

IOException - on error

writeStream

public void writeStream(OutputStream os)
                 throws IOException

This inserts the Streams length, then the actual stream, finally the end of stream/object markers.

This is intended for anyone extending PDFStream, as objects containing streams do no use writeEnd(), and they must be able to write the actual stream.

Parameters:

os - OutputStream to send the object to

Throws:

IOException - on error

getStreamDataString

public String getStreamDataString()

Used for printing stream contents in human-readable form, for debugging.

Returns:

Human-readable string with stream contents in hex