PdfObject is the abstract superclass of all PDF objects.
*
* PDF supports seven basic types of objects: Booleans, numbers, strings, names,
* arrays, dictionaries and streams. In addition, PDF provides a null object.
* Objects may be labeled so that they can be referred to by other objects.
* All these basic PDF objects are described in the 'Portable Document Format
* Reference Manual version 1.3' Chapter 4 (pages 37-54).
*
* @see PdfNull
* @see PdfBoolean
* @see PdfNumber
* @see PdfString
* @see PdfName
* @see PdfArray
* @see PdfDictionary
* @see PdfStream
* @see PdfIndirectReference
*/
public abstract class PdfObject {
// static membervariables (all the possible types of a PdfObject)
/** a possible type of PdfObject */
public static final int BOOLEAN = 1;
/** a possible type of PdfObject */
public static final int NUMBER = 2;
/** a possible type of PdfObject */
public static final int STRING = 3;
/** a possible type of PdfObject */
public static final int NAME = 4;
/** a possible type of PdfObject */
public static final int ARRAY = 5;
/** a possible type of PdfObject */
public static final int DICTIONARY = 6;
/** a possible type of PdfObject */
public static final int STREAM = 7;
/** a possible type of PdfObject */
public static final int NULL = 8;
/** a possible type of PdfObject */
public static final int INDIRECT = 10;
/** This is an empty string used for the PdfNull-object and for an empty PdfString-object. */
public static final String NOTHING = "";
/** This is the default encoding to be used for converting Strings into bytes and vice versa.
* The default encoding is PdfDocEncoding.
*/
public static final String TEXT_PDFDOCENCODING = "PDF";
/** This is the encoding to be used to output text in Unicode. */
public static final String TEXT_UNICODE = "UnicodeBig";
// membervariables
/** the content of this PdfObject */
protected byte[] bytes;
/** the type of this PdfObject */
protected int type;
/**
* Holds value of property indRef.
*/
protected PRIndirectReference indRef;
// constructors
/**
* Constructs a PdfObject of a certain type without any content.
*
* @param type type of the new PdfObject
*/
protected PdfObject(int type) {
this.type = type;
}
/**
* Constructs a PdfObject of a certain type with a certain content.
*
* @param type type of the new PdfObject
* @param content content of the new PdfObject as a String.
*/
protected PdfObject(int type, String content) {
this.type = type;
bytes = PdfEncodings.convertToBytes(content, null);
}
/**
* Constructs a PdfObject of a certain type with a certain content.
*
* @param type type of the new PdfObject
* @param bytes content of the new PdfObject as an array of byte.
*/
protected PdfObject(int type, byte[] bytes) {
this.bytes = bytes;
this.type = type;
}
// methods dealing with the content of this object
/**
* Writes the PDF representation of this PdfObject as an array of bytes to the writer.
* @param writer for backwards compatibility
* @param os the outputstream to write the bytes to.
* @throws IOException
*/
public void toPdf(PdfWriter writer, OutputStream os) throws IOException {
if (bytes != null)
os.write(bytes);
}
/**
* Gets the presentation of this object in a byte array
* @return a byte array
*/
public byte[] getBytes() {
return bytes;
}
/**
* Can this object be in an object stream?
* @return true if this object can be in an object stream.
*/
public boolean canBeInObjStm() {
return (type >= 1 && type <= 6) || type == 8;
}
/**
* Returns the length of the PDF representation of the PdfObject.
*
* In some cases, namely for PdfString and PdfStream,
* this method differs from the method length because length
* returns the length of the actual content of the PdfObject.
* Remark: the actual content of an object is in most cases identical to its representation. * The following statement is always true: length() >= pdfLength().
* * @return a length */ // public int pdfLength() { // return toPdf(null).length; // } /** * Returns theString-representation of this PdfObject.
*
* @return a String
*/
public String toString() {
if (bytes == null)
return super.toString();
else
return PdfEncodings.convertToString(bytes, null);
}
/**
* Returns the length of the actual content of the PdfObject.
*
* In some cases, namely for PdfString and PdfStream,
* this method differs from the method pdfLength because pdfLength
* returns the length of the PDF representation of the object, not of the actual content
* as does the method length.
* Remark: the actual content of an object is in some cases identical to its representation. * The following statement is always true: length() >= pdfLength().
* * @return a length */ public int length() { return toString().length(); } /** * Changes the content of thisPdfObject.
*
* @param content the new content of this PdfObject
*/
protected void setContent(String content) {
bytes = PdfEncodings.convertToBytes(content, null);
}
// methods dealing with the type of this object
/**
* Returns the type of this PdfObject.
*
* @return a type
*/
public int type() {
return type;
}
/**
* Checks if this PdfObject is of the type PdfNull.
*
* @return true or false
*/
public boolean isNull() {
return (this.type == NULL);
}
/**
* Checks if this PdfObject is of the type PdfBoolean.
*
* @return true or false
*/
public boolean isBoolean() {
return (this.type == BOOLEAN);
}
/**
* Checks if this PdfObject is of the type PdfNumber.
*
* @return true or false
*/
public boolean isNumber() {
return (this.type == NUMBER);
}
/**
* Checks if this PdfObject is of the type PdfString.
*
* @return true or false
*/
public boolean isString() {
return (this.type == STRING);
}
/**
* Checks if this PdfObject is of the type PdfName.
*
* @return true or false
*/
public boolean isName() {
return (this.type == NAME);
}
/**
* Checks if this PdfObject is of the type PdfArray.
*
* @return true or false
*/
public boolean isArray() {
return (this.type == ARRAY);
}
/**
* Checks if this PdfObject is of the type PdfDictionary.
*
* @return true or false
*/
public boolean isDictionary() {
return (this.type == DICTIONARY);
}
/**
* Checks if this PdfObject is of the type PdfStream.
*
* @return true or false
*/
public boolean isStream() {
return (this.type == STREAM);
}
/**
* Checks if this is an indirect object.
* @return true if this is an indirect object
*/
public boolean isIndirect() {
return (this.type == INDIRECT);
}
/**
* Getter for property indRef.
* @return Value of property indRef.
*/
public PRIndirectReference getIndRef() {
return this.indRef;
}
/**
* Setter for property indRef.
* @param indRef New value of property indRef.
*/
public void setIndRef(PRIndirectReference indRef) {
this.indRef = indRef;
}
}