org.apache.fop.pdf

Class PDFObject

java.lang.Object

org.apache.fop.pdf.PDFObject

All Implemented Interfaces:

PDFWritable

Direct Known Subclasses:

AbstractPDFStream, PDFAction, PDFAnnotList, PDFArray, PDFCharProcs, PDFCIDFont, PDFCIDSystemInfo, PDFDestination, PDFDictionary, PDFEncryptionJCE, PDFFunction, PDFGState, PDFICCBasedColorSpace, PDFInfo, PDFLink, PDFName, PDFNumber, PDFNumsArray, PDFOutline, PDFOutputIntent, PDFPages, PDFPathPaint, PDFShading, PDFText

public abstract class PDFObject
extends Object
implements PDFWritable

generic PDF object. A PDF Document is essentially a collection of these objects. A PDF Object has a number and a generation (although the generation will always be 0 in new documents).

Field Summary

Fields

Modifier and Type	Field and Description
protected static org.apache.commons.logging.Log	log logger for all PDFObjects (and descendants)

Constructor Summary

Constructors

Constructor and Description
PDFObject() Default constructor.
PDFObject(PDFObject parent) Constructor for direct objects.

Method Summary

Methods

Modifier and Type	Method and Description
protected boolean	contentEquals(PDFObject o) Check if the other PDFObject has the same content as the current object.
static byte[]	encode(String text) Converts text to a byte array for writing to a PDF file.
protected void	encodeBinaryToHexString(byte[] data, OutputStream out) Encodes binary data as hexadecimal string object.
protected byte[]	encodeString(String string) Encodes a String (3.2.3 in PDF 1.4 specs)
protected byte[]	encodeText(String text) Encodes a Text String (3.8.1 in PDF 1.4 specs)
protected void	formatObject(Object obj, OutputStream out, StringBuilder textBuffer) Formats an object for serialization to PDF.
void	getChildren(Set<PDFObject> children)
PDFDocument	getDocument() Returns the parent PDFDocument if assigned.
PDFDocument	getDocumentSafely() Returns the parent PDFDocument, but unlike getDocument() it throws an informative Exception if the parent document is unavailable instead of having a NullPointerException somewhere without a message.
int	getGeneration() Returns this object's generation.
String	getObjectID() Returns the PDF representation of the Object ID.
PDFObjectNumber	getObjectNumber() Returns the object's number.
PDFObject	getParent() Returns this objects's parent.
boolean	hasObjectNumber() Indicates whether this PDFObject has already been assigned an object number.
PDFReference	makeReference() Creates and returns a reference to this object.
int	output(OutputStream stream) Write the PDF represention of this object
void	outputInline(OutputStream out, StringBuilder textBuffer) Writes a "direct object" (inline object) representation to the stream.
String	referencePDF() Returns the PDF representation of a reference to this object.
void	setDocument(PDFDocument doc) Sets the parent PDFDocument.
void	setObjectNumber(int objectNumber)
void	setObjectNumber(PDFDocument document) Sets the object number
void	setObjectNumber(PDFObjectNumber objectNumber)
void	setParent(PDFObject parent) Sets the direct parent object.
protected byte[]	toPDF() Encodes the object as a byte array for output to a PDF file.
protected String	toPDFString() This method returns a String representation of the PDF object.

Methods inherited from class java.lang.Object

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

Field Detail

log

protected static final org.apache.commons.logging.Log log

logger for all PDFObjects (and descendants)

Constructor Detail

PDFObject

public PDFObject()

Default constructor.

PDFObject

public PDFObject(PDFObject parent)

Constructor for direct objects.

Parameters:

parent - the containing PDFObject instance

Method Detail

getObjectNumber

public PDFObjectNumber getObjectNumber()

Returns the object's number.

Returns:

the PDF Object number

hasObjectNumber

public boolean hasObjectNumber()

Indicates whether this PDFObject has already been assigned an object number.

Returns:

True if it has an object number

setObjectNumber

public void setObjectNumber(PDFDocument document)

Sets the object number

setObjectNumber

public void setObjectNumber(PDFObjectNumber objectNumber)

setObjectNumber

public void setObjectNumber(int objectNumber)

getGeneration

public int getGeneration()

Returns this object's generation.

Returns:

the PDF Object generation

getDocument

public final PDFDocument getDocument()

Returns the parent PDFDocument if assigned.

Returns:

the parent PDFDocument (May be null if the parent PDFDocument has not been assigned)

getDocumentSafely

public final PDFDocument getDocumentSafely()

Returns the parent PDFDocument, but unlike getDocument() it throws an informative Exception if the parent document is unavailable instead of having a NullPointerException somewhere without a message.

Returns:

the parent PDFDocument

setDocument

public void setDocument(PDFDocument doc)

Sets the parent PDFDocument.

Parameters:

doc - the PDFDocument.

getParent

public PDFObject getParent()

Returns this objects's parent. The parent is null if it is a "direct object".

Returns:

the parent or null if there's no parent (or it hasn't been set)

setParent

public void setParent(PDFObject parent)

Sets the direct parent object.

Parameters:

parent - the direct parent

getObjectID

public String getObjectID()

Returns the PDF representation of the Object ID.

Returns:

the Object ID

referencePDF

public String referencePDF()

Returns the PDF representation of a reference to this object.

Returns:

the reference string

makeReference

public PDFReference makeReference()

Creates and returns a reference to this object.

Returns:

the object reference

output

public int output(OutputStream stream)
           throws IOException

Write the PDF represention of this object

Parameters:

stream - the stream to write the PDF to

Returns:

the number of bytes written

Throws:

IOException - if there is an error writing to the stream

outputInline

public void outputInline(OutputStream out,
                StringBuilder textBuffer)
                  throws IOException

Writes a "direct object" (inline object) representation to the stream. A text buffer is given for optimized encoding of text content.

IMPORTANT: If you need to write out binary output, call PDFDocument.flushTextBuffer(StringBuilder, OutputStream) before writing any content to the OutputStream!

Specified by:

outputInline in interface PDFWritable

Parameters:

out - the OutputStream (for binary content)

textBuffer - the text buffer for text content

Throws:

IOException - if an I/O error occurs

toPDF

protected byte[] toPDF()

Encodes the object as a byte array for output to a PDF file.

Returns:

PDF string

toPDFString

protected String toPDFString()

This method returns a String representation of the PDF object. The result is normally converted/encoded to a byte array by toPDF(). Only use this method to implement the serialization if the object can be fully represented as text. If the PDF representation of the object contains binary content use toPDF() or output(OutputStream) instead. This applies to any object potentially containing a string object because string object are encrypted and therefore need to be binary.

Returns:

String the String representation

encode

public static final byte[] encode(String text)

Converts text to a byte array for writing to a PDF file.

Parameters:

text - text to convert/encode

Returns:

byte[] the resulting byte array

encodeText

protected byte[] encodeText(String text)

Encodes a Text String (3.8.1 in PDF 1.4 specs)

Parameters:

text - the text to encode

Returns:

byte[] the encoded text

encodeString

protected byte[] encodeString(String string)

Encodes a String (3.2.3 in PDF 1.4 specs)

Parameters:

string - the string to encode

Returns:

byte[] the encoded string

encodeBinaryToHexString

protected void encodeBinaryToHexString(byte[] data,
                           OutputStream out)
                                throws IOException

Encodes binary data as hexadecimal string object.

Parameters:

data - the binary data

out - the OutputStream to write the encoded object to

Throws:

IOException - if an I/O error occurs

formatObject

protected void formatObject(Object obj,
                OutputStream out,
                StringBuilder textBuffer)
                     throws IOException

Formats an object for serialization to PDF.

IMPORTANT: If you need to write out binary output, call PDFDocument.flushTextBuffer(StringBuilder, OutputStream) before writing any content to the OutputStream!

Parameters:

obj - the object

out - the OutputStream to write to

textBuffer - a text buffer for text output

Throws:

IOException - If an I/O error occurs

contentEquals

protected boolean contentEquals(PDFObject o)

Check if the other PDFObject has the same content as the current object.

Note: This function has a contract which is less binding than Object.equals(Object). Whereas equals would require all values to be identical, this method is not required to check everything. In the case of PDFObjects, this means that the overriding function does not have to check for getObjectID().

Parameters:

o - object to compare to.

Returns:

true if the other object has the same content.

getChildren

public void getChildren(Set<PDFObject> children)