javax.print.DocFlavor
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Java™ Platform Standard Ed. 6 |
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java.lang.Object
public class DocFlavor
Class DocFlavor encapsulates an object that specifies the
format in which print data is supplied to a DocPrintJob.
"Doc" is a short, easy-to-pronounce term that means "a piece of print data."
The print data format, or "doc flavor", consists of two things:
Class.getName()byte[] is "[B", for
char[] it is "[C".)
A DocPrintJob obtains its print data by means of interface
Doc. A Doc object lets the DocPrintJob
determine the doc flavor the client can supply. A Doc object
also lets the DocPrintJob obtain an instance of the doc flavor's
representation class, from which the DocPrintJob then obtains
the actual print data.
For client formatted print data, the client determines or knows the print data format. For example the client may have a JPEG encoded image, a URL for HTML code, or a disk file containing plain text in some encoding, possibly obtained from an external source, and requires a way to describe the data format to the print service.
The doc flavor's representation class is a conduit for the JPS
DocPrintJob to obtain a sequence of characters or
bytes from the client. The
doc flavor's MIME type is one of the standard media types telling how to
interpret the sequence of characters or bytes. For a list of standard media
types, see the Internet Assigned Numbers Authority's (IANA's) Media Types
Directory. Interface Doc provides two utility operations,
getReaderForText and
getStreamForBytes(), to help a
Doc object's client extract client formatted print data.
For client formatted print data, the print data representation class is typically one of the following (although other representation classes are permitted):
char[]) -- The print data consists of the
Unicde characters in the array.
String --
The print data consists of the Unicode characters in the string.
java.io.Reader)
-- The print data consists of the Unicode characters read from the stream
up to the end-of-stream.
byte[]) -- The print data consists of the bytes in
the array. The bytes are encoded in the character set specified by the doc
flavor's MIME type. If the MIME type does not specify a character set, the
default character set is US-ASCII.
java.io.InputStream) --
The print data consists of the bytes read from the stream up to the
end-of-stream. The bytes are encoded in the character set specified by the
doc flavor's MIME type. If the MIME type does not specify a character set,
the default character set is US-ASCII.
URL)
-- The print data consists of the bytes read from the URL location.
The bytes are encoded in the character set specified by the doc flavor's
MIME type. If the MIME type does not specify a character set, the default
character set is US-ASCII.
When the representation class is a URL, the print service itself accesses and downloads the document directly from its URL address, without involving the client. The service may be some form of network print service which is executing in a different environment. This means you should not use a URL print data flavor to print a document at a restricted URL that the client can see but the printer cannot see. This also means you should not use a URL print data flavor to print a document stored in a local file that is not available at a URL accessible independently of the client. For example, a file that is not served up by an HTTP server or FTP server. To print such documents, let the client open an input stream on the URL or file and use an input stream data flavor.
For byte print data where the doc flavor's MIME type does not include a
charset parameter, the Java Print Service instance assumes the
US-ASCII character set by default. This is in accordance with
RFC 2046, which says the
default character set is US-ASCII. Note that US-ASCII is a subset of
UTF-8, so in the future this may be widened if a future RFC endorses
UTF-8 as the default in a compatible manner.
Also note that this is different than the behaviour of the Java runtime when interpreting a stream of bytes as text data. That assumes the default encoding for the user's locale. Thus, when spooling a file in local encoding to a Java Print Service it is important to correctly specify the encoding. Developers working in the English locales should be particularly conscious of this, as their platform encoding corresponds to the default mime charset. By this coincidence that particular case may work without specifying the encoding of platform data.
Every instance of the Java virtual machine has a default character encoding determined during virtual-machine startup and typically depends upon the locale and charset being used by the underlying operating system. In a distributed environment there is no gurantee that two VM's share the same default encoding. Thus clients which want to stream platform encoded text data from the host platform to a Java Print Service instance must explicitly declare the charset and not rely on defaults.
The preferred form is the official IANA primary name for an encoding.
Applications which stream text data should always specify the charset
in the mime type, which necessitates obtaining the encoding of the host
platform for data (eg files) stored in that platform's encoding.
A CharSet which corresponds to this and is suitable for use in a
mime-type for a DocFlavor can be obtained
from DocFlavor.hostEncoding
See character encodings for more information on the character encodings supported on the Java platform.
The Java Print Service API does not define any mandatorily supported DocFlavors. However, here are some examples of MIME types that a Java Print Service instance might support for client formatted print data. Nested classes inside class DocFlavor declare predefined static constant DocFlavor objects for these example doc flavors; class DocFlavor's constructor can be used to create an arbitrary doc flavor.
| MIME-Type | Description |
|---|---|
"text/plain" |
Plain text in the default character set (US-ASCII) |
"text/plain; charset=xxx" |
Plain text in character set xxx |
"text/html" |
HyperText Markup Language in the default character set (US-ASCII) |
"text/html; charset=xxx" |
HyperText Markup Language in character set xxx |
In general, preformatted text print data is provided either in a character oriented representation class (character array, String, Reader) or in a byte oriented representation class (byte array, InputStream, URL).
| MIME-Type | Description |
|---|---|
"application/pdf" |
Portable Document Format document |
"application/postscript" |
PostScript document |
"application/vnd.hp-PCL" |
Printer Control Language document |
In general, preformatted PDL print data is provided in a byte oriented representation class (byte array, InputStream, URL).
| MIME-Type | Description |
|---|---|
"image/gif" |
Graphics Interchange Format image |
"image/jpeg" |
Joint Photographic Experts Group image |
"image/png" |
Portable Network Graphics image |
In general, preformatted image print data is provided in a byte oriented representation class (byte array, InputStream, URL).
| MIME-Type | Description |
|---|---|
"application/octet-stream" |
The print data format is unspecified (just an octet stream) |
The printer decides how to interpret the print data; the way this "autosensing" works is implementation dependent. In general, preformatted autosense print data is provided in a byte oriented representation class (byte array, InputStream, URL).
For service formatted print data, the Java Print Service instance
determines the print data format. The doc flavor's representation class
denotes an interface whose methods the DocPrintJob invokes to
determine the content to be printed -- such as a renderable image
interface or a Java printable interface.
The doc flavor's MIME type is the special value
"application/x-java-jvm-local-objectref" indicating the client
will supply a reference to a Java object that implements the interface
named as the representation class.
This MIME type is just a placeholder; what's
important is the print data representation class.
For service formatted print data, the print data representation class is typically one of the following (although other representation classes are permitted). Nested classes inside class DocFlavor declare predefined static constant DocFlavor objects for these example doc flavors; class DocFlavor's constructor can be used to create an arbitrary doc flavor.
RenderableImage. The
printer calls methods
in that interface to obtain the image to be printed.
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.
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.
("text/plain", "java.io.InputStream")
("text/plain; charset=us-ascii", "java.io.InputStream")
("text/plain; charset=utf-8", "java.io.InputStream")
("application/x-java-jvm-local-objectref", "java.awt.image.renderable.RenderableImage")
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.
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.
Furthermore, every Java Print Service instance must fulfill these requirements for processing plain text print data:
The client must itself perform all plain text print data formatting not addressed by the above requirements.
Class DocFlavor in package javax.print.data is similar to class
DataFlavor. Class
DataFlavor
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.
java.awt.datatransfer.DataFlavor
does not guarantee that equivalent data flavors will have the same
serialized representation. DocFlavor does, and can be used in services
which need this.
java.awt.datatransfer.DataFlavor
includes a human presentable name as part of the serialized representation.
This is not appropriate as part of a service matching constraint.
Class DocFlavor's serialized representation uses the following canonical form of a MIME type string. Thus, two doc flavors with MIME types that are not identical but that are equivalent (that have the same canonical form) may be considered equal.
Class DocFlavor's serialized representation also contains the fully-qualified class name of the representation class (a String object), rather than the representation class itself (a Class object). This allows a client to examine the doc flavors a Java Print Service instance supports without having to load the representation classes, which may be problematic for limited-resource clients.
| Nested Class Summary | |
|---|---|
static class |
DocFlavor.BYTE_ARRAY
Class DocFlavor.BYTE_ARRAY provides predefined static constant DocFlavor objects for example doc flavors using a byte array ( byte[]) as the print data representation class. |
static class |
DocFlavor.CHAR_ARRAY
Class DocFlavor.CHAR_ARRAY provides predefined static constant DocFlavor objects for example doc flavors using a character array ( char[]) as the print data representation class. |
static class |
DocFlavor.INPUT_STREAM
Class DocFlavor.INPUT_STREAM provides predefined static constant DocFlavor objects for example doc flavors using a byte stream ( |
static class |
DocFlavor.READER
Class DocFlavor.READER provides predefined static constant DocFlavor objects for example doc flavors using a character stream ( |
static class |
DocFlavor.SERVICE_FORMATTED
Class DocFlavor.SERVICE_FORMATTED provides predefined static constant DocFlavor objects for example doc flavors for service formatted print data. |
static class |
DocFlavor.STRING
Class DocFlavor.STRING provides predefined static constant DocFlavor objects for example doc flavors using a string ( |
static class |
DocFlavor.URL
Class DocFlavor.URL provides predefined static constant DocFlavor objects. |
| Field Summary | |
|---|---|
static String |
hostEncoding
A String representing the host operating system encoding. |
| Constructor Summary | |
|---|---|
DocFlavor(String mimeType,
String className)
Constructs a new doc flavor object from the given MIME type and representation class name. |
|
| Method Summary | |
|---|---|
boolean |
equals(Object obj)
Determines if this doc flavor object is equal to the given object. |
String |
getMediaSubtype()
Returns this doc flavor object's media subtype (from the MIME type). |
String |
getMediaType()
Returns this doc flavor object's media type (from the MIME type). |
String |
getMimeType()
Returns this doc flavor object's MIME type string based on the canonical form. |
String |
getParameter(String paramName)
Returns a String representing a MIME
parameter. |
String |
getRepresentationClassName()
Returns the name of this doc flavor object's representation class. |
int |
hashCode()
Returns a hash code for this doc flavor object. |
String |
toString()
Converts this DocFlavor to a string. |
| Methods inherited from class java.lang.Object |
|---|
clone, finalize, getClass, notify, notifyAll, wait, wait, wait |
| Field Detail |
|---|
public static final String hostEncoding
| Constructor Detail |
|---|
public DocFlavor(String mimeType, String className)
mimeType - MIME media type string.className - Fully-qualified representation class name.
NullPointerException - (unchecked exception) Thrown if mimeType is null or
className is null.
IllegalArgumentException - (unchecked exception) Thrown if mimeType does not
obey the syntax for a MIME media type string.| Method Detail |
|---|
public String getMimeType()
public String getMediaType()
public String getMediaSubtype()
public String getParameter(String paramName)
String representing a MIME
parameter.
Mime types may include parameters which are usually optional.
The charset for text types is a commonly useful example.
This convenience method will return the value of the specified
parameter if one was specified in the mime type for this flavor.
paramName - the name of the paramater. This name is internally
converted to the canonical lower case format before performing
the match.
throws - NullPointerException if paramName is null.public String getRepresentationClassName()
public String toString()
DocFlavor to a string.
public int hashCode()
Object.equals(java.lang.Object),
Hashtablepublic boolean equals(Object obj)
DocFlavor, has a MIME type equivalent to this doc
flavor object's MIME type (that is, the MIME types have the same media
type, media subtype, and parameters), and has the same representation
class name as this doc flavor object. Thus, if two doc flavor objects'
MIME types are the same except for comments, they are considered equal.
However, two doc flavor objects with MIME types of "text/plain" and
"text/plain; charset=US-ASCII" are not considered equal, even though
they represent the same media type (because the default character
set for plain text is US-ASCII).
obj - Object to test.
obj, false
otherwise.Object.hashCode(),
Hashtable
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Java™ Platform Standard Ed. 6 |
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