* <P>
 * <LI>
 * Printable object -- The client supplies an object that implements interface 
 * {@link java.awt.print.Printable Printable}.
 * The printer calls methods in that interface to obtain the pages to be
 * printed, one by one.
 * For each page, the printer supplies a graphics context, and whatever the
 * client draws in that graphics context gets printed. 
 * <P>
 * <LI>
 * Pageable object -- The client supplies an object that implements interface 
 * {@link java.awt.print.Pageable Pageable}. The printer calls 
 * methods in that interface to obtain the pages to be printed, one by one.
 * For each page, the printer supplies a graphics context, and whatever
 * the client draws in that graphics context gets printed. 
 * </UL>
 * <P>
 * <HR>
 * <P>
 * <HR>
 * <H3>Pre-defined Doc Flavors</H3>
 * A Java Print Service instance is not <B><I>required</I></B> to support the 
 * following print data formats and print data representation classes.  In 
 * fact, a developer using this class should <b>never</b> assume that a
 * particular print service supports the document types corresponding to
 * these pre-defined doc flavors.  Always query the print service
 * to determine what doc flavors it supports.  However, 
 * developers who have print services that support these doc flavors are
 * encouraged to refer to the predefined singleton instances created here.
 * <UL>
 * <LI>
 * Plain text print data provided through a byte stream. Specifically, the 
 * following doc flavors are recommended to be supported: 
 * <BR>·  
 * <CODE>("text/plain", "java.io.InputStream")</CODE>
 * <BR>·  
 * <CODE>("text/plain; charset=us-ascii", "java.io.InputStream")</CODE>
 * <BR>·  
 * <CODE>("text/plain; charset=utf-8", "java.io.InputStream")</CODE>
 * <P>
 * <LI>
 * Renderable image objects. Specifically, the following doc flavor is
 * recommended to be supported: 
 * <BR>·  
 * <CODE>("application/x-java-jvm-local-objectref", "java.awt.image.renderable.RenderableImage")</CODE>
 * </UL>
 * <P>
 * A Java Print Service instance is allowed to support any other doc flavors
 * (or none) in addition to the above mandatory ones, at the implementation's
 * choice. 
 * <P>
 * Support for the above doc flavors is desirable so a printing client can rely 
 * on being able to print on any JPS printer, regardless of which doc flavors 
 * the printer supports. If the printer doesn't support the client's preferred 
 * doc flavor, the client can at least print plain text, or the client can 
 * convert its data to a renderable image and print the image. 
 * <P>
 * Furthermore, every Java Print Service instance must fulfill these 
 * requirements for processing plain text print data: 
 * <UL>
 * <LI>
 * The character pair carriage return-line feed (CR-LF) means
 * "go to column 1 of the next line." 
 * <LI>
 * A carriage return (CR) character standing by itself means
 * "go to column 1 of the next line." 
 * <LI>
 * A line feed (LF) character standing by itself means
 * "go to column 1 of the next line." 
 * <LI>
 * </UL>
 * <P>
 * The client must itself perform all plain text print data formatting not 
 * addressed by the above requirements. 
 * <P>
 * <H3>Design Rationale</H3>
 * <P>
 * Class DocFlavor in package javax.print.data is similar to class 
 * {@link java.awt.datatransfer.DataFlavor DataFlavor}. Class 
 * <code>DataFlavor</code>
 * is not used in the Java Print Service (JPS) API 
 * for three reasons which are all rooted in allowing the JPS API to be
 * shared by other print services APIs which may need to run on Java profiles
 * which do not include all of the Java Platform, Standard Edition.
 * <OL TYPE=1>
 * <LI>
 * The JPS API is designed to be used in Java profiles which do not support
 * AWT.
 * <P>
 * <LI>
 * The implementation of class <code>java.awt.datatransfer.DataFlavor</code>
 * does not guarantee that equivalent data flavors will have the same
 * serialized representation. DocFlavor does, and can be used in services
 * which need this.
 * <P>
 * <LI>
 * The implementation of class <code>java.awt.datatransfer.DataFlavor</code>
 * includes a human presentable name as part of the serialized representation.
 * This is not appropriate as part of a service matching constraint.
 * </OL>