https://openjdk.java.net/ 
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 * Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package javax.print;

import java.io.ByteArrayInputStream;
import java.io.CharArrayReader;
import java.io.StringReader;
import java.io.InputStream;
import java.io.IOException;
import java.io.Reader;
import javax.print.attribute.AttributeSetUtilities;
import javax.print.attribute.DocAttributeSet;


This class is an implementation of interface Doc that can be used in many common printing requests. It can handle all of the presently defined "pre-defined" doc flavors defined as static variables in the DocFlavor class. 

In particular this class implements certain required semantics of the
Doc specification as follows:

    

  • constructs a stream for the service if requested and appropriate.

  • ensures the same object is returned for each call on a method.

  • ensures multiple threads can access the Doc

  • performs some validation of that the data matches the doc flavor.


Clients who want to re-use the doc object in other jobs,
or need a MultiDoc will not want to use this class.

 If the print data is a stream, or a print job requests data as a stream, then SimpleDoc does not monitor if the service properly closes the stream after data transfer completion or job termination. Clients may prefer to use provide their own implementation of doc that adds a listener to monitor job completion and to validate that resources such as streams are freed (ie closed). 
/**
 * This class is an implementation of interface {@code Doc} that can
 * be used in many common printing requests.
 * It can handle all of the presently defined "pre-defined" doc flavors
 * defined as static variables in the DocFlavor class.
 * <p>
 * In particular this class implements certain required semantics of the
 * Doc specification as follows:
 * <ul>
 * <li>constructs a stream for the service if requested and appropriate.
 * <li>ensures the same object is returned for each call on a method.
 * <li>ensures multiple threads can access the Doc
 * <li>performs some validation of that the data matches the doc flavor.
 * </ul>
 * Clients who want to re-use the doc object in other jobs,
 * or need a MultiDoc will not want to use this class.
 * <p>
 * If the print data is a stream, or a print job requests data as a
 * stream, then {@code SimpleDoc} does not monitor if the service
 * properly closes the stream after data transfer completion or job
 * termination.
 * Clients may prefer to use provide their own implementation of doc that
 * adds a listener to monitor job completion and to validate that
 * resources such as streams are freed (ie closed).
 */

public final class SimpleDoc implements Doc {

    private DocFlavor flavor;
    private DocAttributeSet attributes;
    private Object printData;
    private Reader reader;
    private InputStream inStream;

    
Constructs a SimpleDoc with the specified print data, doc flavor and doc attribute set. 
Params:
  • printData – the print data object
  • flavor – the DocFlavor object
  • attributes – a DocAttributeSet, which can be null
Throws:
  • IllegalArgumentException – if flavor or printData is null, or the printData does not correspond to the specified doc flavor--for example, the data is not of the type specified as the representation in the DocFlavor.
/**
     * Constructs a {@code SimpleDoc} with the specified
     * print data, doc flavor and doc attribute set.
     * @param printData the print data object
     * @param flavor the {@code DocFlavor} object
     * @param attributes a {@code DocAttributeSet}, which can
     *                   be {@code null}
     * @throws IllegalArgumentException if {@code flavor} or
     *         {@code printData} is {@code null}, or the
     *         {@code printData} does not correspond
     *         to the specified doc flavor--for example, the data is
     *         not of the type specified as the representation in the
     *         {@code DocFlavor}.
     */
    public SimpleDoc(Object printData,
                     DocFlavor flavor, DocAttributeSet attributes) {

       if (flavor == null || printData == null) {
           throw new IllegalArgumentException("null argument(s)");
       }

       Class<?> repClass = null;
       try {
            String className = flavor.getRepresentationClassName();
            sun.reflect.misc.ReflectUtil.checkPackageAccess(className);
            repClass = Class.forName(className, false,
                              Thread.currentThread().getContextClassLoader());
       } catch (Throwable e) {
           throw new IllegalArgumentException("unknown representation class");
       }

       if (!repClass.isInstance(printData)) {
           throw new IllegalArgumentException("data is not of declared type");
       }

       this.flavor = flavor;
       if (attributes != null) {
           this.attributes = AttributeSetUtilities.unmodifiableView(attributes);
       }
       this.printData = printData;
    }

   
Determines the doc flavor in which this doc object will supply its
piece of print data.

Returns: Doc flavor.
/**
     * Determines the doc flavor in which this doc object will supply its
     * piece of print data.
     *
     * @return  Doc flavor.
     */
    public DocFlavor getDocFlavor() {
        return flavor;
    }

    
Obtains the set of printing attributes for this doc object. If the
returned attribute set includes an instance of a particular attribute
X, the printer must use that attribute value for this doc,
overriding any value of attribute X in the job's attribute set.
If the returned attribute set does not include an instance
of a particular attribute X or if null is returned, the printer
must consult the job's attribute set to obtain the value for
attribute X, and if not found there, the printer must use an
implementation-dependent default value. The returned attribute set is
unmodifiable.

Returns: Unmodifiable set of printing attributes for this doc, or null
         to obtain all attribute values from the job's attribute
         set.
/**
     * Obtains the set of printing attributes for this doc object. If the
     * returned attribute set includes an instance of a particular attribute
     * <I>X,</I> the printer must use that attribute value for this doc,
     * overriding any value of attribute <I>X</I> in the job's attribute set.
     * If the returned attribute set does not include an instance
     * of a particular attribute <I>X</I> or if null is returned, the printer
     * must consult the job's attribute set to obtain the value for
     * attribute <I>X,</I> and if not found there, the printer must use an
     * implementation-dependent default value. The returned attribute set is
     * unmodifiable.
     *
     * @return  Unmodifiable set of printing attributes for this doc, or null
     *          to obtain all attribute values from the job's attribute
     *          set.
     */
    public DocAttributeSet getAttributes() {
        return attributes;
    }

    /*
     * Obtains the print data representation object that contains this doc
     * object's piece of print data in the format corresponding to the
     * supported doc flavor.
     * The {@code getPrintData()} method returns an instance of
     * the representation class whose name is given by
     * {@link DocFlavor#getRepresentationClassName() getRepresentationClassName},
     * and the return value can be cast
     * from class Object to that representation class.
     *
     * @return  Print data representation object.
     *
     * @exception  IOException if the representation class is a stream and
     *     there was an I/O error while constructing the stream.
     */
    public Object getPrintData() throws IOException {
        return printData;
    }

    
Obtains a reader for extracting character print data from this doc. The Doc implementation is required to support this method if the DocFlavor has one of the following print data representation classes, and return null otherwise: 
    

  •  char[] 
  •  java.lang.String 
  •  java.io.Reader 
 The doc's print data representation object is used to construct and return a Reader for reading the print data as a stream of characters from the print data representation object. However, if the print data representation object is itself a Reader then the print data representation object is simply returned. 
Throws:
  • IOException – if there was an I/O error while creating
            the reader.
Returns: a Reader for reading the print data characters from this doc. If a reader cannot be provided because this doc does not meet the criteria stated above, null is returned.
/**
     * Obtains a reader for extracting character print data from this doc.
     * The {@code Doc} implementation is required to support this
     * method if the {@code DocFlavor} has one of the following print
     * data representation classes, and return {@code null}
     * otherwise:
     * <UL>
     * <LI> {@code char[]}
     * <LI> {@code java.lang.String}
     * <LI> {@code java.io.Reader}
     * </UL>
     * The doc's print data representation object is used to construct and
     * return a {@code Reader} for reading the print data as a stream
     * of characters from the print data representation object.
     * However, if the print data representation object is itself a
     * {@code Reader} then the print data representation object is
     * simply returned.
     *
     * @return  a {@code Reader} for reading the print data
     *          characters from this doc.
     *          If a reader cannot be provided because this doc does not meet
     *          the criteria stated above, {@code null} is returned.
     *
     * @exception  IOException if there was an I/O error while creating
     *             the reader.
     */
    public Reader getReaderForText() throws IOException {

        if (printData instanceof Reader) {
            return (Reader)printData;
        }

        synchronized (this) {
            if (reader != null) {
                return reader;
            }

            if (printData instanceof char[]) {
               reader = new CharArrayReader((char[])printData);
            }
            else if (printData instanceof String) {
                reader = new StringReader((String)printData);
            }
        }
        return reader;
    }

    
Obtains an input stream for extracting byte print data from this doc. The Doc implementation is required to support this method if the DocFlavor has one of the following print data representation classes; otherwise this method returns null: 
    

  •  byte[] 
  •  java.io.InputStream 

The doc's print data representation object is obtained.  Then, an
input stream for reading the print data
from the print data representation object as a stream of bytes is
created and returned.
However, if the print data representation object is itself an
input stream then the print data representation object is simply
returned.

Throws:
  • IOException – 
    if there was an I/O error while creating the input stream.
Returns: an InputStream for reading the print data bytes from this doc. If an input stream cannot be provided because this doc does not meet the criteria stated above, null is returned.
/**
     * Obtains an input stream for extracting byte print data from
     * this doc.
     * The {@code Doc} implementation is required to support this
     * method if the {@code DocFlavor} has one of the following print
     * data representation classes; otherwise this method
     * returns {@code null}:
     * <UL>
     * <LI> {@code byte[]}
     * <LI> {@code java.io.InputStream}
     * </UL>
     * The doc's print data representation object is obtained.  Then, an
     * input stream for reading the print data
     * from the print data representation object as a stream of bytes is
     * created and returned.
     * However, if the print data representation object is itself an
     * input stream then the print data representation object is simply
     * returned.
     *
     * @return  an {@code InputStream} for reading the print data
     *          bytes from this doc.  If an input stream cannot be
     *          provided because this doc does not meet
     *          the criteria stated above, {@code null} is returned.
     *
     * @exception  IOException
     *     if there was an I/O error while creating the input stream.
     */
    public InputStream getStreamForBytes() throws IOException {

        if (printData instanceof InputStream) {
            return (InputStream)printData;
        }

        synchronized (this) {
            if (inStream != null) {
                return inStream;
            }

            if (printData instanceof byte[]) {
               inStream = new ByteArrayInputStream((byte[])printData);
            }
        }
        return inStream;
    }

}