Java tutorial
/* * * This file is part of the iText (R) project. Copyright (c) 1998-2019 iText Group NV * Authors: Bruno Lowagie, Paulo Soares, et al. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License version 3 * as published by the Free Software Foundation with the addition of the * following permission added to Section 15 as permitted in Section 7(a): * FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY * ITEXT GROUP. ITEXT GROUP DISCLAIMS THE WARRANTY OF NON INFRINGEMENT * OF THIRD PARTY RIGHTS * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY * or FITNESS FOR A PARTICULAR PURPOSE. * See the GNU Affero General Public License for more details. * You should have received a copy of the GNU Affero General Public License * along with this program; if not, see http://www.gnu.org/licenses or write to * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, * Boston, MA, 02110-1301 USA, or download the license from the following URL: * http://itextpdf.com/terms-of-use/ * * The interactive user interfaces in modified source and object code versions * of this program must display Appropriate Legal Notices, as required under * Section 5 of the GNU Affero General Public License. * * In accordance with Section 7(b) of the GNU Affero General Public License, * a covered work must retain the producer line in every PDF that is created * or manipulated using iText. * * You can be released from the requirements of the license by purchasing * a commercial license. Buying such a license is mandatory as soon as you * develop commercial activities involving the iText software without * disclosing the source code of your own applications. * These activities include: offering paid services to customers as an ASP, * serving PDFs on the fly in a web application, shipping iText with a closed * source product. * * For more information, please contact iText Software Corp. at this * address: sales@itextpdf.com */ package com.itextpdf.text.pdf; import com.itextpdf.text.pdf.internal.PdfIsoKeys; import java.io.IOException; import java.io.OutputStream; import java.io.Serializable; /** * <CODE>PdfObject</CODE> is the abstract superclass of all PDF objects. * <P> * 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.<BR> * 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 implements Serializable { // CONSTANTS /** A possible type of <CODE>PdfObject</CODE> */ public static final int BOOLEAN = 1; /** A possible type of <CODE>PdfObject</CODE> */ public static final int NUMBER = 2; /** A possible type of <CODE>PdfObject</CODE> */ public static final int STRING = 3; /** A possible type of <CODE>PdfObject</CODE> */ public static final int NAME = 4; /** A possible type of <CODE>PdfObject</CODE> */ public static final int ARRAY = 5; /** A possible type of <CODE>PdfObject</CODE> */ public static final int DICTIONARY = 6; /** A possible type of <CODE>PdfObject</CODE> */ public static final int STREAM = 7; /** A possible type of <CODE>PdfObject</CODE> */ public static final int NULL = 8; /** A possible type of <CODE>PdfObject</CODE> */ public static final int INDIRECT = 10; /** An empty string used for the <CODE>PdfNull</CODE>-object and for an empty <CODE>PdfString</CODE>-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"; // CLASS VARIABLES /** The content of this <CODE>PdfObject</CODE> */ protected byte[] bytes; /** The type of this <CODE>PdfObject</CODE> */ protected int type; /** Holds the indirect reference. */ protected PRIndirectReference indRef; // CONSTRUCTORS /** * Constructs a <CODE>PdfObject</CODE> of a certain <VAR>type</VAR> * without any <VAR>content</VAR>. * * @param type type of the new <CODE>PdfObject</CODE> */ protected PdfObject(int type) { this.type = type; } /** * Constructs a <CODE>PdfObject</CODE> of a certain <VAR>type</VAR> * with a certain <VAR>content</VAR>. * * @param type type of the new <CODE>PdfObject</CODE> * @param content content of the new <CODE>PdfObject</CODE> as a * <CODE>String</CODE>. */ protected PdfObject(int type, String content) { this.type = type; bytes = PdfEncodings.convertToBytes(content, null); } /** * Constructs a <CODE>PdfObject</CODE> of a certain <VAR>type</VAR> * with a certain <VAR>content</VAR>. * * @param type type of the new <CODE>PdfObject</CODE> * @param bytes content of the new <CODE>PdfObject</CODE> as an array of * <CODE>byte</CODE>. */ 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 <CODE>PdfObject</CODE> as an * array of <CODE>byte</CODE>s to the writer. * * @param writer for backwards compatibility * @param os The <CODE>OutputStream</CODE> to write the bytes to. * @throws IOException */ public void toPdf(PdfWriter writer, OutputStream os) throws IOException { if (bytes != null) { PdfWriter.checkPdfIsoConformance(writer, PdfIsoKeys.PDFISOKEY_OBJECT, this); os.write(bytes); } } /** * Returns the <CODE>String</CODE>-representation of this * <CODE>PdfObject</CODE>. * * @return a <CODE>String</CODE> */ public String toString() { if (bytes == null) return super.toString(); return PdfEncodings.convertToString(bytes, null); } /** * Gets the presentation of this object in a byte array * * @return a byte array */ public byte[] getBytes() { return bytes; } /** * Whether this object can be contained in an object stream. * * PdfObjects of type STREAM OR INDIRECT can not be contained in an * object stream. * * @return <CODE>true</CODE> if this object can be in an object stream. * Otherwise <CODE>false</CODE> */ public boolean canBeInObjStm() { switch (type) { case NULL: case BOOLEAN: case NUMBER: case STRING: case NAME: case ARRAY: case DICTIONARY: return true; case STREAM: case INDIRECT: default: return false; } } /** * Returns the length of the actual content of the <CODE>PdfObject</CODE>. * <P> * In some cases, namely for <CODE>PdfString</CODE> and <CODE>PdfStream</CODE>, * this method differs from the method <CODE>pdfLength</CODE> because <CODE>pdfLength</CODE> * returns the length of the PDF representation of the object, not of the actual content * as does the method <CODE>length</CODE>.</P> * <P> * Remark: the actual content of an object is in some cases identical to its representation. * The following statement is always true: length() >= pdfLength().</P> * * @return The length as <CODE>int</CODE> */ public int length() { return toString().length(); } /** * Changes the content of this <CODE>PdfObject</CODE>. * * @param content the new content of this <CODE>PdfObject</CODE> */ protected void setContent(String content) { bytes = PdfEncodings.convertToBytes(content, null); } // methods dealing with the type of this object /** * Returns the type of this <CODE>PdfObject</CODE>. * * May be either of: * - <VAR>NULL</VAR>: A <CODE>PdfNull</CODE> * - <VAR>BOOLEAN</VAR>: A <CODE>PdfBoolean</CODE> * - <VAR>NUMBER</VAR>: A <CODE>PdfNumber</CODE> * - <VAR>STRING</VAR>: A <CODE>PdfString</CODE> * - <VAR>NAME</VAR>: A <CODE>PdfName</CODE> * - <VAR>ARRAY</VAR>: A <CODE>PdfArray</CODE> * - <VAR>DICTIONARY</VAR>: A <CODE>PdfDictionary</CODE> * - <VAR>STREAM</VAR>: A <CODE>PdfStream</CODE> * - <VAR>INDIRECT</VAR>: ><CODE>PdfIndirectObject</CODE> * * @return The type */ public int type() { return type; } /** * Checks if this <CODE>PdfObject</CODE> is of the type * <CODE>PdfNull</CODE>. * * @return <CODE>true</CODE> or <CODE>false</CODE> */ public boolean isNull() { return (type == NULL); } /** * Checks if this <CODE>PdfObject</CODE> is of the type * <CODE>PdfBoolean</CODE>. * * @return <CODE>true</CODE> or <CODE>false</CODE> */ public boolean isBoolean() { return (type == BOOLEAN); } /** * Checks if this <CODE>PdfObject</CODE> is of the type * <CODE>PdfNumber</CODE>. * * @return <CODE>true</CODE> or <CODE>false</CODE> */ public boolean isNumber() { return (type == NUMBER); } /** * Checks if this <CODE>PdfObject</CODE> is of the type * <CODE>PdfString</CODE>. * * @return <CODE>true</CODE> or <CODE>false</CODE> */ public boolean isString() { return (type == STRING); } /** * Checks if this <CODE>PdfObject</CODE> is of the type * <CODE>PdfName</CODE>. * * @return <CODE>true</CODE> or <CODE>false</CODE> */ public boolean isName() { return (type == NAME); } /** * Checks if this <CODE>PdfObject</CODE> is of the type * <CODE>PdfArray</CODE>. * * @return <CODE>true</CODE> or <CODE>false</CODE> */ public boolean isArray() { return (type == ARRAY); } /** * Checks if this <CODE>PdfObject</CODE> is of the type * <CODE>PdfDictionary</CODE>. * * @return <CODE>true</CODE> or <CODE>false</CODE> */ public boolean isDictionary() { return (type == DICTIONARY); } /** * Checks if this <CODE>PdfObject</CODE> is of the type * <CODE>PdfStream</CODE>. * * @return <CODE>true</CODE> or <CODE>false</CODE> */ public boolean isStream() { return (type == STREAM); } /** * Checks if this <CODE>PdfObject</CODE> is of the type * <CODE>PdfIndirectObject</CODE>. * * @return <CODE>true</CODE> if this is an indirect object, * otherwise <CODE>false</CODE> */ public boolean isIndirect() { return (type == INDIRECT); } /** * Get the indirect reference * * @return A <CODE>PdfIndirectReference</CODE> */ public PRIndirectReference getIndRef() { return indRef; } /** * Set the indirect reference * * @param indRef New value as a <CODE>PdfIndirectReference</CODE> */ public void setIndRef(PRIndirectReference indRef) { this.indRef = indRef; } }