com.lowagie.text.pdf

Class PdfStream

java.lang.Object

com.lowagie.text.pdf.PdfObject

com.lowagie.text.pdf.PdfDictionary

com.lowagie.text.pdf.PdfStream

Direct Known Subclasses:

PdfEFStream, PdfFormXObject, PdfICCBased, PdfImage, PdfPattern, PRStream

public class PdfStream
extends PdfDictionary

PdfStream is the Pdf stream object.

A stream, like a string, is a sequence of characters. However, an application can read a small portion of a stream at a time, while a string must be read in its entirety. For this reason, objects with potentially large amounts of data, such as images and page descriptions, are represented as streams.
A stream consists of a dictionary that describes a sequence of characters, followed by the keyword stream, followed by zero or more lines of characters, followed by the keyword endstream.
All streams must be PdfIndirectObjects. The stream dictionary must be a direct object. The keyword stream that follows the stream dictionary should be followed by a carriage return and linefeed or just a linefeed.
Remark: In this version only the FLATEDECODE-filter is supported.
This object is described in the 'Portable Document Format Reference Manual version 1.7' section 3.2.7 (page 60-63).

See Also:

PdfObject, PdfDictionary

Field Summary

Fields

Modifier and Type	Field and Description
static int	BEST_COMPRESSION A possible compression level.
static int	BEST_SPEED A possible compression level.
protected boolean	compressed is the stream compressed?
protected int	compressionLevel The level of compression.
static int	DEFAULT_COMPRESSION A possible compression level.
protected InputStream	inputStream
protected int	inputStreamLength
static int	NO_COMPRESSION A possible compression level.
protected int	rawLength
protected PdfIndirectReference	ref
protected ByteArrayOutputStream	streamBytes
protected PdfWriter	writer

Fields inherited from class com.lowagie.text.pdf.PdfDictionary

CATALOG, FONT, hashMap, OUTLINES, PAGE, PAGES

Fields inherited from class com.lowagie.text.pdf.PdfObject

ARRAY, BOOLEAN, bytes, DICTIONARY, INDIRECT, indRef, NAME, NOTHING, NULL, NUMBER, STREAM, STRING, TEXT_PDFDOCENCODING, TEXT_UNICODE, type

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	PdfStream() Constructs a PdfStream-object.
	PdfStream(byte[] bytes) Constructs a PdfStream-object.
	PdfStream(InputStream inputStream, PdfWriter writer) Creates an efficient stream.

Method Summary

Modifier and Type	Method and Description
void	flateCompress() Compresses the stream.
void	flateCompress(int compressionLevel) Compresses the stream.
int	getRawLength() Gets the raw length of the stream.
protected void	superToPdf(PdfWriter writer, OutputStream os)
void	toPdf(PdfWriter writer, OutputStream os) Writes the PDF representation of this PdfDictionary as an array of byte to the given OutputStream.
String	toString() Returns a string representation of this PdfDictionary.
void	writeContent(OutputStream os) Writes the data content to an OutputStream.
void	writeLength() Writes the stream length to the PdfWriter.

Methods inherited from class com.lowagie.text.pdf.PdfDictionary

contains, get, getAsArray, getAsBoolean, getAsDict, getAsIndirectObject, getAsName, getAsNumber, getAsStream, getAsString, getDirectObject, getKeys, isCatalog, isFont, isOutlineTree, isPage, isPages, merge, mergeDifferent, put, putAll, putEx, remove, size

Methods inherited from class com.lowagie.text.pdf.PdfObject

canBeInObjStm, getBytes, getIndRef, isArray, isBoolean, isDictionary, isIndirect, isName, isNull, isNumber, isStream, isString, length, setContent, setIndRef, type

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_COMPRESSION

public static final int DEFAULT_COMPRESSION

A possible compression level.

Since:

2.1.3

See Also:

Constant Field Values

NO_COMPRESSION

public static final int NO_COMPRESSION

A possible compression level.

Since:

2.1.3

See Also:

Constant Field Values

BEST_SPEED

public static final int BEST_SPEED

A possible compression level.

Since:

2.1.3

See Also:

Constant Field Values

BEST_COMPRESSION

public static final int BEST_COMPRESSION

A possible compression level.

Since:

2.1.3

See Also:

Constant Field Values

compressed

protected boolean compressed

is the stream compressed?

compressionLevel

protected int compressionLevel

The level of compression.

Since:

2.1.3

streamBytes

protected ByteArrayOutputStream streamBytes

inputStream

protected InputStream inputStream

ref

protected PdfIndirectReference ref

inputStreamLength

protected int inputStreamLength

writer

protected PdfWriter writer

rawLength

protected int rawLength

Constructor Detail

PdfStream

public PdfStream(byte[] bytes)

Constructs a PdfStream-object.

Parameters:

bytes - content of the new PdfObject as an array of byte.

PdfStream

public PdfStream(InputStream inputStream,
                 PdfWriter writer)

Creates an efficient stream. No temporary array is ever created. The InputStream is totally consumed but is not closed. The general usage is:

 InputStream in = ...;
 PdfStream stream = new PdfStream(in, writer);
 stream.flateCompress();
 writer.addToBody(stream);
 stream.writeLength();
 in.close();
 

Parameters:

inputStream - the data to write to this stream

writer - the PdfWriter for this stream

PdfStream

protected PdfStream()

Constructs a PdfStream-object.

Method Detail

writeLength

public void writeLength()
                 throws IOException

Writes the stream length to the PdfWriter.

This method must be called and can only be called if the constructor PdfStream(InputStream,PdfWriter) is used to create the stream.

Throws:

IOException - on error

See Also:

PdfStream(InputStream,PdfWriter)

getRawLength

public int getRawLength()

Gets the raw length of the stream.

Returns:

the raw length of the stream

flateCompress

public void flateCompress()

Compresses the stream.

flateCompress

public void flateCompress(int compressionLevel)

Compresses the stream.

Parameters:

compressionLevel - the compression level (0 = best speed, 9 = best compression, -1 is default)

Since:

2.1.3

superToPdf

protected void superToPdf(PdfWriter writer,
                          OutputStream os)
                   throws IOException

Throws:

IOException

toPdf

public void toPdf(PdfWriter writer,
                  OutputStream os)
           throws IOException

Description copied from class: PdfDictionary

Writes the PDF representation of this PdfDictionary as an array of byte to the given OutputStream.

Overrides:

toPdf in class PdfDictionary

Parameters:

writer - for backwards compatibility

os - the OutputStream to write the bytes to.

Throws:

IOException

See Also:

PdfDictionary.toPdf(com.lowagie.text.pdf.PdfWriter, java.io.OutputStream)

writeContent

public void writeContent(OutputStream os)
                  throws IOException

Writes the data content to an OutputStream.

Parameters:

os - the destination to write to

Throws:

IOException - on error

toString

public String toString()

Description copied from class: PdfDictionary

Returns a string representation of this PdfDictionary. The string doesn't contain any of the content of this dictionary. Rather the string "dictionary" is returned, possibly followed by the type of this PdfDictionary, if set.

Overrides:

toString in class PdfDictionary

Returns:

the string representation of this PdfDictionary

See Also:

PdfObject.toString()