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	/*
	* Copyright (c) 2000, 2013, 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
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package javax.print;

	import java.io.InputStream;
	import java.io.IOException;
	import java.io.Reader;

	import javax.print.attribute.DocAttributeSet;


	/**
	* Interface Doc specifies the interface for an object that supplies one piece
	* of print data for a Print Job. "Doc" is a short, easy-to-pronounce term
	* that means "a piece of print data." The client passes to the Print Job an
	* object that implements interface Doc, and the Print Job calls methods on
	* that object to obtain the print data. The Doc interface lets a Print Job:
	* <UL>
	* <LI>
	* Determine the format, or "doc flavor" (class {@link DocFlavor DocFlavor}),
	* in which the print data is available. A doc flavor designates the print
	* data format (a MIME type) and the representation class of the object
	* from which the print data comes.
	* <P>
	* <LI>
	* Obtain the print data representation object, which is an instance of the
	* doc flavor's representation class. The Print Job can then obtain the actual
	* print data from the representation object.
	* <P>
	* <LI>
	* Obtain the printing attributes that specify additional characteristics of
	* the doc or that specify processing instructions to be applied to the doc.
	* Printing attributes are defined in package {@link javax.print.attribute
	* javax.print.attribute}. The doc returns its printing attributes stored in
	* an {@link javax.print.attribute.DocAttributeSet javax.print.attribute.DocAttributeSet}.
	* </UL>
	* <P>
	* Each method in an implementation of interface Doc is permitted always to
	* return the same object each time the method is called.
	* This has implications
	* for a Print Job or other caller of a doc object whose print data
	* representation object "consumes" the print data as the caller obtains the
	* print data, such as a print data representation object which is a stream.
	* Once the Print Job has called {@link #getPrintData()
	* getPrintData()} and obtained the stream, any further calls to
	* {@link #getPrintData() getPrintData()} will return the same
	* stream object upon which reading may already be in progress, <I>not</I> a new
	* stream object that will re-read the print data from the beginning. Specifying
	* a doc object to behave this way simplifies the implementation of doc objects,
	* and is justified on the grounds that a particular doc is intended to convey
	* print data only to one Print Job, not to several different Print Jobs. (To
	* convey the same print data to several different Print Jobs, you have to
	* create several different doc objects on top of the same print data source.)
	* <P>
	* Interface Doc affords considerable implementation flexibility. The print data
	* might already be in existence when the doc object is constructed. In this
	* case the objects returned by the doc's methods can be supplied to the doc's
	* constructor, be stored in the doc ahead of time, and simply be returned when
	* called for. Alternatively, the print data might not exist yet when the doc
	* object is constructed. In this case the doc object might provide a "lazy"
	* implementation that generates the print data representation object (and/or
	* the print data) only when the Print Job calls for it (when the Print Job
	* calls the {@link #getPrintData() getPrintData()} method).
	* <P>
	* There is no restriction on the number of client threads that may be
	* simultaneously accessing the same doc. Therefore, all implementations of
	* interface Doc must be designed to be multiple thread safe.
	* <p>
	* However there can only be one consumer of the print data obtained from a
	* Doc.
	* <p>
	* If print data is obtained from the client as a stream, by calling Doc's
	* <code>getReaderForText()</code> or <code>getStreamForBytes()</code>
	* methods, or because the print data source is already an InputStream or
	* Reader, then the print service should always close these streams for the
	* client on all job completion conditions. With the following caveat.
	* If the print data is itself a stream, the service will always close it.
	* If the print data is otherwise something that can be requested as a stream,
	* the service will only close the stream if it has obtained the stream before
	* terminating. That is, just because a print service might request data as
	* a stream does not mean that it will, with the implications that Doc
	* implementors which rely on the service to close them should create such
	* streams only in response to a request from the service.
	* <P>
	* <HR>
	*/
	public interface Doc {

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

	/**
	* 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()</CODE> method returns an instance of
	* the representation class whose name is given by <CODE>{@link
	* #getDocFlavor() getDocFlavor()}.{@link
	* DocFlavor#getRepresentationClassName()
	* getRepresentationClassName()}</CODE>, and the return value can be cast
	* from class Object to that representation class.
	*
	* @return Print data representation object.
	*
	* @exception IOException
	* Thrown if the representation class is a stream and there was an I/O
	* error while constructing the stream.
	*/
	public Object getPrintData() throws IOException;

	/**
	* 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();

	/**
	* 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:
	* <UL>
	* <LI> char[]
	* <LI> java.lang.String
	* <LI> java.io.Reader
	* </UL>
	* 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.
	* <P>
	* @return 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.
	*
	* @exception IOException
	* Thrown if there was an I/O error while creating the reader.
	*/
	public Reader getReaderForText() throws IOException;

	/**
	* 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, and return null otherwise:
	* <UL>
	* <LI> byte[]
	* <LI> java.io.InputStream
	* </UL>
	* This 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.
	* <P>
	* @return Input stream 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.
	*
	* @exception IOException
	* Thrown if there was an I/O error while creating the input stream.
	*/
	public InputStream getStreamForBytes() throws IOException;

	}

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