001    /* Doc.java --
002       Copyright (C) 2004, 2006 Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    
039    package javax.print;
040    
041    import java.io.IOException;
042    import java.io.InputStream;
043    import java.io.Reader;
044    
045    import javax.print.attribute.DocAttributeSet;
046    
047    /**
048     * <code>Doc</code> specifies the interface for print services how to obtain 
049     * the print data and document specific attributes for printing. 
050     * <p>
051     * The print data is always passed to a {@link javax.print.DocPrintJob} object 
052     * as a <code>Doc</code> object which allows the print services to:
053     * <ul>
054     * <li>Determine the actual document format of the supplied print data. This
055     *  is supplied as a {@link javax.print.DocFlavor} object with the MIME type
056     *  and the representation class of the print data.</li>
057     * <li>Obtain the print data either in its representation class or depending
058     *  on the document format through convenience methods as a 
059     *  {@link java.io.Reader} or an {@link java.io.InputStream}.</li>
060     * <li>Obtain the document's attribute set specifying the attributes which
061     *  apply to this document instance.</li>
062     * </ul> 
063     * </p><p>
064     * Every method of a <code>Doc</code> implementation has to return always the 
065     * same object on every method call. Therefore if the print job consumes the 
066     * print data via a stream or a reader object it can read only once the 
067     * supplied print data. Implementations of this interface have to be thread 
068     * safe. 
069     * </p>
070     * 
071     * @author Michael Koch (konqueror@gmx.de)
072     */
073    public interface Doc
074    {
075      /**
076       * Returns the unmodifiable view of the attributes of this doc object.
077       * <p>
078       * The attributes of this doc's attributes set overrides attributes of 
079       * the same category in the print job's attribute set. If an attribute 
080       * is not available in this doc's attributes set or <code>null</code>
081       * is returned the attributes of the same category of the print job are
082       * used. 
083       * </p>
084       * 
085       * @return The unmodifiable attributes set, or <code>null</code>.
086       */
087      DocAttributeSet getAttributes();
088    
089      /**
090       * Returns the flavor of this doc objects print data.
091       * 
092       * @return The document flavor.
093       */
094      DocFlavor getDocFlavor();
095    
096      /**
097       * Returns the print data of this doc object.
098       * <p>
099       * The returned object is an instance as described by the associated
100       * document flavor ({@link DocFlavor#getRepresentationClassName()})
101       * and can be cast to this representation class.
102       * </p>
103       * 
104       * @return The print data in the representation class.
105       * @throws IOException if representation class is a stream and I/O
106       * exception occures.
107       */
108      Object getPrintData() throws IOException;
109    
110      /**
111       * Returns a <code>Reader</code> object for extracting character print data
112       * from this document.
113       * <p>
114       * This method is supported if the document flavor is of type:
115       * <ul>
116       * <li><code>char[]</code></li>
117       * <li><code>java.lang.String</code></li>
118       * <li><code>java.io.Reader</code></li>
119       * </ul>
120       * otherwise this method returns <code>null</code>.
121       * </p> 
122       * 
123       * @return The <code>Reader</code> object, or <code>null</code>.
124       * 
125       * @throws IOException if an error occurs.
126       */
127      Reader getReaderForText() throws IOException;
128    
129      /**
130       * Returns an <code>InputStream</code> object for extracting byte print data
131       * from this document.
132       * <p>
133       * This method is supported if the document flavor is of type:
134       * <ul>
135       * <li><code>byte[]</code></li>
136       * <li><code>java.io.InputStream</code></li>
137       * </ul>
138       * otherwise this method returns <code>null</code>.
139       * </p> 
140       * 
141       * @return The <code>InputStream</code> object, or <code>null</code>.
142       * 
143       * @throws IOException if an error occurs.
144       */
145      InputStream getStreamForBytes() throws IOException;
146    }